Evidence about public-health measures

Evidence syntheses on this webpage are organized by:

vaccine safety and efficacy and real-world effectiveness
infection prevention (personal protection like wearing masks, with service limitations that support infection prevention captured in the corresponding government sector on the economic and social responses webpage)
infection control (screening, quarantining, testing, isolation, contact tracing, and susceptibility tracking)
broader public-health measures (risk stratification, outbreak management, and pandemic tracking).

Drugs used as chemoprophylaxis for COVID-19 are addressed on the clinical management webpage, given their benefits accrue only at the individual level (not at the population level, as occurs with vaccinations through herd immunity).

We continue to add evidence syntheses to this webpage as we harvest and process weekly updates from ‘high-yield, high quality’ sources of evidence syntheses and as we add new sources. More details are available about the context for the inventory, our approach to developing and maintain it, and tips for using it. Similar webpages are available for evidence about the clinical management of COVID-19 and related conditions, health-system arrangements, and economic and social responses.

Broad and specific decisions			Criteria for 'best evidence synthesis'			Details to support relevance assessment	Additional decision-relevant details			Citation
Broad and specific decisions			Date of last search	Quality (AMSTAR) rating	Evidence-certainty (e.g., GRADE) assessment available	Key findings	Living evidence synthesis	Type of synthesis	Type of question	Citation
Infection prevention
	Vaccination
		Safety and efficacy	2021-03-26	10/11	Yes	[BioNTech/Fosun Pharma/Pfizer vaccine] Compared to placebo, vaccination with BNT162b2 probably reduces the incidence of symptomatic cases of COVID-19 substantially, although there remains uncertainty about the impact on reducing mortality or severe disease. The evidence for any difference in serious adverse events is uncertain, although the vaccination probably increases the incidence of any adverse event.	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. BNT162b2 vs placebo (BioNTech/Fosun Pharma/Pfizer ). 2020.
			2021-03-26	10/11	Yes	[Gamaleya Research Institute vaccine] Compared to placebo, vaccination with Gam-COVID-Vac rAd26-S/rAd5-S probably reduces the incidence of symptomatic and severe cases of COVID-19 substantially, although there remains uncertainty about the impact on reducing mortality. The vaccination may not increase the incidence of serious adverse event, but the incidence of any adverse event was not reported	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. Gam-COVID-Vac rAd26-S/rAd5-S vs Placebo (Gamaleya Research Institute of Epidemiology and Microbiology). 2020.
			2021-03-26	10/11	Yes	[ModernaTX vaccine] Compared to placebo, vaccination with mRNA-1273 probably reduces the incidence of symptomatic cases of COVID-19 substantially, and it may reduce severe disease, while the incidence of serious adverse events is probably not increased	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. mRNA-1273 vs placebo (ModernaTX). 2020.
			2021-03-26	10/11	Yes	[Oxford/AstraZeneca vaccine] Compared to vaccinating with MedACWY (meningitis vaccine), vaccination with ChAdOx1 probably reduces the incidence of symptomatic cases of COVID-19 as well as the number of positive tests, and may reduce severe or critical disease and hospitalisations. The effects on mortality are uncertain, and adverse events are probably less frequent	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. ChAdOx1 vs MenACWY (University of Oxford/AstraZeneca ). 2020.
			N/A (protocol)	n/a	Yes	[Protocol - results not yet available] A review assessing the benefits and harms of available vaccines for COVID-19 is currently being conducted	Yes (row content last updated on 2021-02-16)	Protocol	Benefits and harms	Kwasi Korang S, Juul S, Eik Nielsen E, Feinberg J, Siddiqui F, Ong G, et al. Vaccines to prevent COVID-19: A protocol for a living systematic review with network meta-analysis including individual patient data (The LIVING VACCINE Project), Systematic Reviews. 2020;9(1):262.
			2021-02-12	10/11	Yes	Synthesis pending	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Siemieniuk R, Bartoszko JJ, Ge L, Zeraatkar D, Izcovich A, Kum E, et al. Update to living systematic review on drug treatments for covid-19. BMJ. 2021;370:m2980.
		'Real world' effectiveness	N/A (protocol)	n/a	Yes	[Protocol - results not yet available] A systematic review evaluating the differential benefits and harms of available vaccines among different ethnic groups is currently being conducted	No	Protocol	Benefits and harms	Wei GX, Wang H, Song Q, Su W, Li N, Liang Q. The effectiveness, protection rates and adverse outcomes of Pfizer-Biontech's BNT162b2, Moderna's mRNA-1273, and Oxford University / AstraZeneca's ChAdOx1/ AZD1222 vaccines in different ethnic groups:a systematic review and meta-analysis. PROSPERO. 2021;CRD42021234071.
			N/A (Protocol)	n/a	Yes	[Protocol - results not yet available] A systematic review evaluating the cost-effectiveness of available SARS-COV-2 vaccines is currently being conducted	No	Protocol	Costs and cost-effectiveness	Rocha-Filho C, Pinto ACP, da Rocha AP, Civile VT, Carvas Junior N, Ramalho GS, et al. Vaccines for preventing SARS-CoV-2 infection: protocol for a rapid systematic review and network meta-analysis with economics evidence. PROSPERO. 2020; CRD42020216544.
			N/A (Protocol)	n/a	No	[Protocol - results not yet available] A review evaluating the safety of COVID-19 candidate vaccines on pregnant women is currently being conducted	No	Protocol	Benefits and harms	Ciapponi A, Bardach A, Comande D, Berrueta M, Mazzoni A, Buekens P. Effects of COVID-19 candidate vaccines or their components on pregnancy safety outcomes. PROSPERO. 2021; CRD42021234185
		Vaccine roll-out (see health-system arrangements)
	Personal protection
		Washing hands	2020-04-17	4/9	No	Hand hygiene combined with the use of masks in community settings appears to be more protective against coranaviruses and other infectious respiratory viruses than either approach in isolation	No	Rapid review	Benefits and harms	MacIntyre CR & Chughtai AA. A rapid systematic review of the efficacy of face masks and respirators against coronaviruses and other respiratory transmissible viruses for the community, healthcare workers and sick patients. Int J Nurs Stud. 2020;108:103629.
			2020-04-25	8/11	No	Studies from the pre COVID-19 era show that proper hand-hygiene methods combined with the use of face masks may reduce the rate of influenza-like-illnesses in community settings	No	Full review	Benefit and harms	Aggarwal N, Dwarakanathan V, Gautam N, Ray A. Facemasks for prevention of viral respiratory infections in community settings: A systematic review and meta-analysis. Indian J Public Health. 2020;64(Supplement):S192-S200.
		Wearing masks*	2020-05-03	11/11	Yes	Large reductions in risk of viral infections may be possible with the use of masks, with N95 or similar respirators more likely to lead to greater reductions compared to disposable surgical masks or other reusable masks	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Chu DK, Akl EA, Duda S, et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis [published online ahead of print, 2020 Jun 1]. Lancet. 2020;S0140-6736(20)31142-9. doi:10.1016/S0140-6736(20)31142-9
			2021-02-02	6/10	No	Whereas no research was found on the effectiveness of wearing masks in community settings for COVID-19, studies on SARS and influenza showed that the evidence for wearing masks is stronger in healthcare settings compared to community settings	Yes (row content last updated on 2021-04-12)	Rapid review	Benefits and harms	Chou R, Dana T, Jungbauer R, Weeks C. Update Alert 5: Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings. Annals of Internal Medicine. 2021.
			Not specified	5/11	Yes	Cloth face masks and facial coverings worn by the general public appear to be an effective approach for source protection (i.e., reducing virus transmission by the wearer) while also protecting the wearer	No	Rapid review	Benefits and harms	The British Academy. Face masks and coverings for the general public: Behavioural knowledge, effectiveness of cloth coverings and public messaging. Oxford, UK: The British Academy. 2020;
			2020-05-18	7/11	No	Randomized and non-randomized studies from the pre-COVID-19 era show insufficient reporting of data on serious harms of face masks, with discomfort and irritation the only reported downsides	No	Full review	Benefits and harms	Bakhit M, Krzyzaniak N, Scott, A, Clark J, Glasziou P, Del Mar C. Downsides of Face Masks and Possible Mitigation Strategies: A Systematic Review and Meta-Analysis. MedRxiv 2020.
			2020-04-30	10/10	Yes	Compared to medical masks, cloth masks may have a lower filtration efficiency and penetration level, and are probably worse for protecting the wearer	No	Full review	Benefits and harms	Santos M, Torres D, Coutinho Cardoso P, Pandis N, Flores-Mir C, Medeiros R, et al. Are cloth masks a substitute to medical masks in reducing transmission and contamination? A systematic review. Brazilian Oral Research. 2020;34:e123.
			N/A (protocol)	n/a	Yes	[Protocol - results not yet available] A systematic review exploring the psychosocial impact of wearing masks in public and the effects on the development of children and adolescents is currently being conducted	No	Protocol	Benefits and harms	Freiberg A, Drossler S, Horvath K, Kampf D, Apfelbacher C, Hahne TM, et al. Impact of wearing face masks in public during the COVID-19 pandemic on the psychosocial effects on development in children and adolescents. PROSPERO. 2020; CRD42020223217
		Wearing personal protective equipment	2020-05-03	11/11	Yes	Low certainty evidence suggests N95 respirators and eye protection can lead to a reduction in viral infections	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Chu DK, Akl EA, Duda S, et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis [published online ahead of print, 2020 Jun 1]. Lancet. 2020;S0140-6736(20)31142-9. doi:10.1016/S0140-6736(20)31142-9
		Wearing personal protective equipment	2021-02-02	6/10	No	PPE use by healthcare workers (masks, gloves, gowns and eye protection) has been found to be one of the strongest factors associated with reduced risk of coronavirus infection, with the most consistent associations observed for masks	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Chou R, Dana T, Jungbauer R, Weeks C. Update Alert 5: Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings. Annals of Internal Medicine. 2021.
			2020-04-08	8/10	No	The safety of different decontamination methods for reusing surgical masks in clinical settings is uncertain	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Zorko DJ, Gertsman S, O'Hearn K, et al. DECONTAMINATION INTERVENTIONS FOR THE REUSE OF SURGICAL MASK PERSONAL PROTECTIVE EQUIPMENT: A SYSTEMATIC REVIEW [published online ahead of print, 2020 Jul 9]. J Hosp Infect. 2020;S0195-6701(20)30337-6. doi:10.1016/j.jhin.2020.07.007
			2020-05-18	7/11	No	Adherence to wearing masks was found to be significantly higher for surgical/medical masks, compared to N95/P2 respirators	No	Full review	Benefits and harms	Bakhit M, Krzyzaniak N, Scott, A, Clark J, Glasziou P, Del Mar C. Downsides of Face Masks and Possible Mitigation Strategies: A Systematic Review and Meta-Analysis. MedRxiv 2020.
			2020-06-01	7/10	Yes	The effectiveness of using powered air-purifying respirators by healthcare workers to prevent risk of infection is uncertain, but they probably improve comfort compared to other respirators	No	Full review	Benefits and harms	Licina A, Silvers A, Stuart RL. Use of powered air-purifying respirator (PAPR) by healthcare workers for preventing highly infectious viral diseases-A systematic review of evidence. Systematic reviews. 2020;9:173.
			2020-03-20	9/10	Yes	The differences between different types of PPE (e.g., attire, gloves, gowns, types of respirators), and levels of protection for preventing exposure to contaminated fluids among healthcare workers is uncertain	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Verbeek J, Rajamaki B, Ijaz S, et al. Personal Protective Equipment for Preventing Highly Infectious Diseases due to Exposure to Contaminated Body Fluids in Healthcare Staff. Cochrane Database Syst Rev 2020;4(4):CD011621.
			2020-03-20	9/10	Yes	The effectiveness of most PPE modifications for preventing exposure to contaminated body fluids in health care workers is uncertain, although easy to doff gowns, and gown-glove improvements may be better than standard gowns and gloves	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Verbeek J, Rajamaki B, Ijaz S, et al. Personal Protective Equipment for Preventing Highly Infectious Diseases due to Exposure to Contaminated Body Fluids in Healthcare Staff. Cochrane Database Syst Rev 2020;4(4):CD011621.
			2020-04-23	6/9	No	Limited evidence suggests that there is a low probability of viral carriage on the surgical masks of healthcare workers treating patients with clinical respiratory illnesses, and no studies about the relationship between carriage and clinical outcomes were identified	No	Full review	Other	Jones P, Roberts S, Hotu C, Kamona S. What proportion of healthcare worker masks carry virus? A systematic review [published online ahead of print, 2020 Jun 24]. Emerg Med Australas. 2020;10.1111/1742-6723.13581. doi:10.1111/1742-6723.13581
			Not specified	4/9	No	Limited evidence was found on the effectiveness of 3D printing of N95 respirators	No	Rapid review	Other	Ontario Health Quality. 3D Printing of N95 Respirators and Face Shields: Supplemental Information. Toronto: 2020.
			2021-03-24	6/10	No	Using PPE was found to be the strongest factor associated with reducing risk of coronavirus infection among health care workers [Review of observational studies]	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Chou R, Dana T, Buckley D, Selph S, Fu R, Totten A. Update alert 8: Epidemiology of and risk factors for coronavirus infection in health care workers. Ann Intern Med 2021; L21-0034.
			2020-05-25	4/9	No	The evidence on extending the use or reuse of PPE is mainly focused on masks, suggesting that extended use of a respirator (N95 or equivalent) is safer than intermittent reuse	Yes (row content last updated on 2021-04-12)	Rapid review	Other	COVID-19 Critical Intelligence Unit. Extended use or reuse of personal protective equipment. St Leonards, NSW: Agency for Clinical Innovation; 2020.
			2020-07-28	4/9	No	No evidence was found evaluating the clinical effectiveness of using face shields in pre-hospital settings	No	Rapid review	Benefits and harms	Kumar D & Spry C. Face shields in pre-hospital settings: Clinical effectiveness and guidelines. Ottawa: Canadian Agency for Drugs and Technologies in Health (CADTH). 2020.
			2020-10-22	8/11	Yes	Whereas wearing any type of mask probably reduces the incidence of respiratory infections, N95 respirators or equivalent were found to be the most effective mask type, compared to surgical, medical and non-medical facemasks	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Kim MS, Seong D, Li H, Chun SK, Park Y, Lee M, et al. Comparative efficacy of N95, surgical, medical, and non-medical facemasks in protection of respiratory virus infection: A living systematic review and network meta-analysis (preprint). The Lancet. 2021.
			2020-12-27	9/11	No	A high proportion of adverse events (mainly skin reactions) has been reported among healthcare workers using personal protective equipment [Review of observational studies of low to moderate quality]	No	Full review	Other	Galanis PA, Vraka I, Fragkou D, Bilali A, Kaitelidou D. Impact of personal protective equipment use on health care workers physical health during the COVID-19 pandemic: A systematic review and meta-analysis. medRxiv. 2021.
		Disinfecting surfaces and facilities	2020-04-24	5/9	No	Temperature and humidity appear to have an important effect on how long SARS-CoV-2 can live on surfaces (from a few hours up to 28 days), and alcohol-based hand rub formulations recommended by WHO are an efficient disinfectatnt agent for surfaces [Review of studies of unknown quality]	No	Full review	Other	Noorimotlagh Z, Mirzaee SA, Jaafarzadeh N, Maleki M, Kalvandi G, Karami C. A systematic review of emerging human coronavirus (SARS-CoV-2) outbreak: Focus on disinfection methods, environmental survival, and control and prevention strategies. Environmental Science and Pollution Research. 2020.
			2020-12-31	8/9	No	Although they may not be viable, fragments of SARS-CoV-2 can probably be detected on surfaces in community settings for up to seven days. Cleaning and disinfecting procedures probably decrease or eliminate SARS-CoV-2 fragments	Yes (row content last updated on 2021-04-12)	Rapid review	Other	National Collaborating Centre for Methods and Tools. Rapid Review Update 1: What is known about how long the virus can survive with potential for infection on surfaces found in community settings? Hamilton, ON: National Collaborating Centre for Methods and Tools; 2021.
			2020-07-10	5/10	No	Not enough evidence exists to determine survivability on various surfaces and optimal disinfection methods for these surfaces, or about fomite transmissibility of SARS-CoV-2	Yes (row content last updated on 2021-04-12)	Full review	Other	Bedrosian N, Mitchell E, Rohm E, Rothe M, Kelly C, String G, et al. A systematic review of surface contamination, stability, and disinfection data on SARS-CoV-2 (Through July 10, 2020). Environmental Science Technology. 2020.
			2020-05-27	5/9	No	Environmental disenfection may result in viral inactivation on surfaces [Review of mainly laboratory studies of unknown quality]	No	Rapid review	Other	Shimabukuro PMS, Duarte ML, Imoto AM, Atallah AN, Franco ESB, Peccin MS, et al. Environmental cleaning to prevent COVID-19 infection: A rapid systematic review. Sao Paulo Medical Journal. 2020.
		Physical distancing	2020-05-03	11/11	Yes	Physical distancing of more than one metre probably results in a large reduction in risk of viral infections	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Chu DK, Akl EA, Duda S, et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis [published online ahead of print, 2020 Jun 1]. Lancet. 2020;S0140-6736(20)31142-9. doi:10.1016/S0140-6736(20)31142-9
			2021-03-26	8/9	No	Synthesis pending	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. Social Distancing at Sports Training vs No Access to Sports Training Facilities. 2020.
			2020-07-29	8/11	No	Global prevalence of depression and anxiety during the COVID-19 pandemic have been estimated to be 24% and 21% respectively, representing a concurrent epidemic, with public transportation closures the only mitigation measure found to be associated with increased anxiety	No	Full review	Other	Castaldelli-Maia JM, Marziali ME, Lu Z, Martins SS. Investigating the effect of national government physical distancing measures on depression and anxiety during the COVID-19 pandemic through meta-analysis and meta-regression. 2020.
			2020-05-07	7/10	No	Low-to-moderate quality evidence showed that the potential negative effects of physical distancing on mental health are exacerbated by quarantine duration, infection fear, inadequate supplies, inadequate information, financial loss, and stigma [Review of syntheses and single studies conducted during the COVID-19 and pre-COVID-19 era]	Yes (row content last updated on 2021-04-12)	Rapid review	Benefits and harms	National Collaborating Centre for Methods and Tools. How does physical distancing impact mental health?. Hamilton: National Collaborating Centre for Methods and Tools; 2020.
			2020-07-01	5/9	No	When economic evaluations model a long time horizon, social distancing measures were found to be more cost-effective than quarantine, non-intervention, or herd immunity	No	Full review	Costs and cost-effectiveness	Rezapour A, Souresrafil A, Peighambari MM, Heidarali M, Tashakori-Miyanroudi M. Economic evaluation studies of programs against COVID-19: A systematic review of the literature. International Journal of Surgery. 2020;85:10-18.
		Temporal distancing
		Altering sexual activities	N/A (Protocol)	n/a	No	[Protocol - results not yet available] A systematic review to evaluate whether SARS-CoV-2 can be sexually transmitted is currently being conducted	Yes (row content last updated on 2020-12-07)	Protocol	Other	Duarte G, Ortiz-Muñoz L, Morales M, Rada G. Sexual Transmission of SARS-CoV-2 Virus, and its Role in the Spread of COVID-19: a Living Systematic Review Protocol. PROSPERO 2020; CRD42020189368.
		Public-focused behaviour-change supports	2020-05-01	6/11	No	People touch their faces as often as 50 times per hour, and their T-zone (eyes, nose, mouth and chin) as much as 68 times per hour, which requires extensive behaviour intervention and community awareness [Review of observational studies]	No	Full review	Other	Rahman J. Mumin J. Fakhruddin B. How frequently do we touch facial T-zone: A systematic review. 2020;86(1):75.
			Not specified	5/11	Yes	A rapid review found that public adherence to wearing face masks depends on several socio-behavioral factors, and that consistent and effective public messaging is key to supporting implementation	No	Rapid review	Other	The British Academy. Face masks and coverings for the general public: Behavioural knowledge, effectiveness of cloth coverings and public messaging. Oxford, UK: The British Academy. 2020;
			2021-02-12	7/10	No	A review of communication strategies to mitigate risk behaviours found low to moderate evidence suggesting clear, action-oriented and tailored messages that are repeated frequently and delivered by trusted leaders probably improve risk communication, and that addressing uncertainty and previous errors in communication may help to build trust, while framing messages positively in relation to collective action rather than individual action is probably more effective	Yes (row content last updated on 2021-04-12)	Rapid review	Benefits and harms	National Collaborating Centre for Methods and Tools. Rapid Review Update 1: What are best practices for risk communication and strategies to mitigate risk behaviours? National Collaborating Centre for Methods and Tools. 2021;
			N/A (protocol)	n/a	Yes	[Protocol - results not yet available] A systematic review assessing barriers and facilitators to population-wide adherence to infection prevention and control measures is currently being conducted	No	Protocol	Other	Mendonca K, Jacome A, Silva B, Patino C, Chaves G, Alchieri JC et al. Barriers and facilitators to populational adherence to prevention and control measures of COVID-19 and other respiratory infectious diseases: a rapid qualitative evidence synthesis. PROSPERO. 2020;CRD42020205750.
		Health worker and essential worker-focused behaviour change supports for the above	2020-03-26	7/9	Yes	The design and content of infection prevention and control guidelines, how they are communicated, and whether there is adequate organizational support, training, and access to personal protective equipment affects adherence among healthcare workers	No	Rapid review	Other	Houghton C, Meskell P, Delaney H, et al. Barriers and Facilitators to Healthcare Workers' Adherence with Infection Prevention and Control (IPC) Guidelines for Respiratory Infectious Diseases: a Rapid Qualitative Evidence Synthesis. Cochrane Database Syst Rev 2020;4(4):CD013582.
			2020-03-20	9/10	Yes	There is uncertainty about the effectiveness of procedures to prevent exposure to contaminated body fluids in health care workers, although providing donning and doffing instructions as well as using extra sanitation for doffing may reduce the risk of contamination	Yes (row content last updated on 2021-04-12)	Full review	Benefits and harms	Verbeek J, Rajamaki B, Ijaz S, et al. Personal Protective Equipment for Preventing Highly Infectious Diseases due to Exposure to Contaminated Body Fluids in Healthcare Staff. Cochrane Database Syst Rev 2020;4(4):CD011621.
			2021-03-26	8/9	Yes	Synthesis pending	Yes (row content last updated on 2021-03-29)	Full review	Benefits and harms	COVID NMA. Video training in PPE donning and doffing vs live instructor-led training in PPE donning and doffing. 2020.
		Other	2020-07-21	6/6	Yes	No completed studies were found that evaluated the effects of healthcare workers' use of antimicrobial mouthwash and nasal sprays to protect them when treating suspected COVID-19 patients	No	Full review	Benefits and harms	Burton MJ, Clarkson JE, Goulao B, Glenny A-M, McBain AJ, Schilder AGM, et al. Use of antimicrobial mouthwashes (gargling) and nasal sprays by healthcare workers to protect them when treating patients with suspected or confirmed COVID‐19 infection. Cochrane Database of Systematic Reviews. 2020;(9):Art. No.: CD013626. DOI: 10.1002/14651858.CD013626.pub2.
			2020-06-01	6/6	Yes	No completed studies were found that evaluated the effects of healthcare workers' use of antimicrobial mouthwash and nasal sprays to protect them when undertaking aerosol-generating procedures on suspected COVID-19 patients	No	Full review	Benefits and harms	Burton MJ, Clarkson JE, Goulao B, Glenny A-M, McBain AJ, Schilder AGM, et al. Antimicrobial mouthwashes (gargling) and nasal sprays to protect healthcare workers when undertaking aerosol‐generating procedures (AGPs) on patients without suspected or confirmed COVID‐19 infection. Cochrane Database of Systematic Reviews. 2020;(9):Art. No.: CD013628. DOI: 10.1002/14651858.CD013628.pub2.
			2020-04-24	8/10	No	Using povidone-iodine (PVP-I) solutions for 15 seconds has shown to be the most effective mouthwash for reducing viral load of COVID-19 in human saliva, and insufficient evidence was found on the uses of hydrogen peroxide	No	Full review	Benefits and harms	Cavalcante-Leão BL, de Araujo CM, Basso IB, Schroder AGD, Guariza-Filho O, Ravazzi GC, et al. Is there scientific evidence of the mouthwashes effectiveness in reducing viral load in Covid-19? A systematic review. Journal of Clinical and Experimental Dentistry. 2021;13(2):e179-e189.
			N/A (Protocol)	n/a	Yes	[Protocol - results not yet available] A review evaluating the effects of mouth-rinses on the viral load of SARS-CoV-2 in saliva is currently being conducted	Yes (row content last updated on 2020-11-30)	Protocol	Benefits and harms	Vásquez AAH, Barrenechea-Pulache A, Comandé D, Azañedo D. Effect of mouth-rinses on viral load of SARS-CoV-2 in saliva: A living systematic review and meta-analysis. PROSPERO. 2021; CRD42021240561
	Service limitations (see relevant sector within economic and social responses)
Infection control
	Screening
		Targets	2020-05-01	7/9	No	Study design, quality, and prevalence estimates of early SARS-CoV-2 serosurveys are heterogeneous (ranging from 0.4% to 59.3%), suggesting that the urgency to examine seroprevalence may have compromised methodological rigour	Yes (row content last updated on 2021-04-12)	Rapid review	Other	Bobrovitz N, Arora R, Yan T, Rahim H, Duarte N, Bouher E, et al. Lessons from a Rapid Systematic Review of Early SARS-CoV-2 Serosurveys. MedRxiv 2020.
			2020-07-15	8/10	No	Evidence of signs or symptoms that can be used to determine if patients presenting to primary care or outpatient settings have COVID-19 is currently uncertain, but the presence of anosmia or ageusia may be useful as a red flag for COVID-19 and the presence of fever or cough, given their high sensitivities, may also be useful to identify people for further testing	No	Full review	Other	Struyf T, Deeks JJ, Dinnes J, et al. Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19 disease. Cochrane Database Syst Rev. 2020;7:CD013665. Published 2020 Jul 7. doi:10.1002/14651858.CD013665
			2020-07-03	7/10	No	Despite substantial variation on the secondary attack rates, asymptomatic individuals were responsible for fewer secondary infections compared to symptomatic and pre-symptomatic individuals	Yes (row content last updated on 2021-04-12)	Full review	Other	Qiu X, Nergiz AI, Maraolo AE, Bogoch II, Low N, Cevik M. Defining the role of asymptomatic SARS-CoV-2 transmission: A living systematic review. medRxiv. 2020.
			2020-06-10	7/11	No	On average 20% of patients with SARS-CoV-2 remain asymptomatic through the course of infection, and these infections may have lower secondary attack rates compared to symptomatic infections and there is variability in the rate of presymptomatic infections [Review of observational studies]	Yes (row content last updated on 2021-04-12)	Full review	Other	Buitrago-Garcia D, Egli-Gany D, Counotte MJ, Hossmann S, Imeri H, Ipekci AM, et al. Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis. PLoS Medicine. 2020;17(9):e1003346.
			2020-04-17	6/10	Yes	While no evidence was found on universal screening for SARS-CoV-2 infection, modelling studies suggest that screening at travel hubs may slightly slow the importation of infected cases	No	Rapid review	Benefits and harms	Viswanathan M, Kahwati L, Jahn B, Giger K, Dobrescu AI, Hill C, et al. Universal screening for SARS‐CoV‐2 infection: A rapid review. Cochrane Database of Systematic Reviews 2020, Issue 9. Art. No.: CD013718. DOI: 10.1002/14651858.CD013718.
			2020-08-25	8/11	No	A meta-analysis found that 23% of confirmed SARS-CoV-2 infections are asymptomatic, but this varies depending on the setting in which the infections occur [Review of observational studies with important heterogeneity]	No	Rapid review	Benefits and harms	Beale S, Hayward A, Shallcross L, Aldridge RW, Fragaszy E. A rapid review and meta-analysis of the asymptomatic proportion of PCR-confirmed SARS-CoV-2 infections in community settings. Wellcome Open Research. 2020;5:266.
			2020-06-08	7/10	No	Limited evidence suggests that mass testing combined with lockdowns might be an effective strategy to control COVID-19, compared to lockdown alone [Review of observational and modelling studies]	No	Full review	Benefits and harms	Johanna N, Citrawijaya H, Wangge G. Mass screening vs lockdown vs combination of both to control COVID-19: A systematic review. Journal of Public Health Research. 2020;9(4):2011.
			2020-05-07	8/11	No	It is estimated that COVID-19 asymptomatic cases are more common in children and healthcare workers compared to the general population [Review of studies of variable quality and substantial heterogeneity]	No	Full review	Benefits and harms	Chen C, Zhu C, Yan D, Liu H, Li D, Zhou Y, et al. The epidemiological and radiographical characteristics of asymptomatic infections with the novel coronavirus (covid-19): A systematic review and meta-analysis. International Journal of Infectious Diseases. 2021.
			2020-04-30	9/11	No	Children over 12 months of age generally experience milder symptoms than adults, but younger children were more likely to experience critical illness and vomiting [Review of observational studies]	No	Full review	Other	Cui X, Zhao Z, Zhang T, Guo W, Guo W, Zheng J, et al. A systematic review and meta-analysis of children with coronavirus 2019 (COVID-19). Journal of medical virology. 2020.
			2020-05-29	9/11	No	Non-contact infrared thermometers and thermal scanners may have reasonable sensitivity and specificity for diagnosing fever, but the sensitivity of thermal scanners decreased in the context of pandemics [Review of studies conducted during the COVID-19, H1N1, seasonal influenza and SARS outbreaks]	No	Full review	Test accuracy	Aggarwal N, Garg M, Dwarakanathan V, Gautam N, Kumar SS, Jadon RS, et al. Diagnostic accuracy of non-contact infrared thermometers and thermal scanners: A systematic review and meta-analysis. Journal of Travel Medicine. 2020.
			2020-04-17	6/10	Yes	The certainty of the evidence is low or very low for the accuracy of different universal screening methods, but in general they are shown to have low sensitivity	No	Rapid review	Test accuracy	Viswanathan M, Kahwati L, Jahn B, Giger K, Dobrescu AI, Hill C, et al. Universal screening for SARS‐CoV‐2 infection: A rapid review. Cochrane Database of Systematic Reviews 2020, Issue 9. Art. No.: CD013718. DOI: 10.1002/14651858.CD013718.
			2020-07-01	5/9	No	Economic evaluations show that screening programs may be a cost-effective strategy to control COVID-19	No	Full review	Costs and cost-effectiveness	Rezapour A, Souresrafil A, Peighambari MM, Heidarali M, Tashakori-Miyanroudi M. Economic evaluation studies of programs against COVID-19: A systematic review of the literature. International Journal of Surgery. 2020;85:10-18.
			2020-05-01	9/11	No	Fever, cough, myalgia and dyspnea were found to be the most common symptoms among COVID-19 patients [Review of studies of variable quality and substantial heterogeneity]	No	Full review	Other	Jafari A, Falahatkar S, Yekta K, Mohammad H. COVID-19 clinical characteristics, complications and comorbidity: An updated systemic review and meta-analysis. The Lancet. 2020.
			2021-01-08	8/11	No	COVID-19 in children is usually associated with a favourable clinical course, and the most prevalent clinical manifestations are fever and cough [Review of studies of variable quality]	No	Full review	Other	Irfan O, Muttalib F, Tang K, Jiang L, Lassi ZS, Bhutta Z. Clinical characteristics, treatment and outcomes of paediatric COVID-19: A systematic review and meta-analysis. Archives of Disease in Childhood. 2021:archdischild-2020-321385.
		Locations (and frequency if applicable)	2021-02-26	8/9	Yes	This rapid review found insufficient real-world evidence to determine the effects of travel related measures to contain the COVID-19 pandemic, although some studies from the pre-COVID era found screening at borders as a possible approach for detecting infected travellers	No	Rapid review	Benefits and harms	Burns J, Movsisyan A, Stratil JM, Coenen M, Emmert-Fees KMF, Geffert K, et al. Travel‐related control measures to contain the COVID‐19 pandemic: A rapid review. Cochrane Database of Systematic Reviews.2020;(9):Art. No.: CD013717. DOI: 10.1002/14651858.CD013717.
			2020-05-22	4/10	No	Insufficient evidence to assess the effectiveness of workplace screening programs for reducing the spread of COVID-19 was found in healthcare settings, but some evidence suggests that multifaceted strategies are most likely to be effective in detecting staff illness [Review of studies mainly conducted during the pre-COVID-19 era]	No	Rapid review	Benefits and harms	Erdmann R. Rapid review: Effectiveness of workplace screening programs for reducing the spread of COVID-19 in healthcare settings. Edmonton, AB: Alberta Health Services, COVID-19 Scientific Advisory Group; 2020.
			2020-07-27	9/11	No	While mass testing of residents and staff as well as guidance on infection prevention and control measures were frequently implemented in long-term care facilities, their effects are uncertain [Review mainly based on observational studies of low quality]	No	Rapid review	Other	Frazer K, Mitchell L, Stokes D, Lacey E, Crowley E, Kelleher C. A rapid systematic review of measures to protect older people in long term care facilities from COVID-19. medRxiv. 2020.
	Quarantining of exposed or potentially exposed individuals
		Voluntary or imposed	2020-04-01	9/11	No	One randomized controlled trial has found that quarantining workers during an epidemic when members of their household are infected can control the spread of influenza-like-illness, but increases their individual risk of infection	No	Full review	Benefits and harms	Jefferson T, Jones M, Al Ansari L, Bawazeer G, Beller E, Clark J, et al. Physical Interventions to Interrupt or Reduce the Spread of Respiratory Viruses. Part I - Face Masks, Eye Protection and Person Distancing: Systematic Review and Meta-Analysis. MedRxiv 2020.
			2020-06-23	7/10	Yes	Evidence of how effective quarantines are alone or in combination with other measures for people who were in contact with a confirmed/suspected case of COVID-19 mostly comes from mathematical modelling studies, which consistently show that they can be important for reducing COVID-19 incidence and mortality	Yes (row content last updated on 2021-04-12)	Rapid review	Other	Nussbaumer-Streit B, Mayr V, Dobrescu AIulia, Chapman A, Persad E, Klerings I, et al. Quarantine alone or in combination with other public health measures to control COVID‐19: A rapid review. Cochrane Database of Systematic Reviews. 2020;(4)CD013574.
			2021-02-26	8/9	Yes	The effectiveness of quarantining travellers is uncertain	No	Rapid review	Benefits and harms	Burns J, Movsisyan A, Stratil JM, Coenen M, Emmert-Fees KMF, Geffert K, et al. Travel‐related control measures to contain the COVID‐19 pandemic: A rapid review. Cochrane Database of Systematic Reviews.2020;(9):Art. No.: CD013717. DOI: 10.1002/14651858.CD013717.
			2020-06-02	5/9	No	Whereas the majority of jurisdictions explored require a 14-day quarantine for people exposed to COVID-19, there is important variability in the duration of quarantine from symptoms onset, and after having ended symptoms	No	Full review	Other	National Collaborating Centre for Methods and Tools. Rapid Review: Are any jurisdictions using isolation periods other than 14 days in response to COVID-19?. Hamilton, ON: National Collaborating Centre for Methods and Tools; 2020.
			2020-05-01	9/11	No	The average incubation period of patients with COVID-19 has been estimated to be five days, while the duration of illness to dyspnea, onset of symptoms to hospital admission, hospital admission to ICU admission, and first symptom to death occurred in an average of 13, six, five and 17 days, respectively [Review of studies of variable quality and substantial heterogeneity]	No	Full review	Other	Jafari A, Falahatkar S, Yekta K, Mohammad H. COVID-19 clinical characteristics, complications and comorbidity: An updated systemic review and meta-analysis. The Lancet. 2020.
	Testing
		Optimizing testing across different types of individuals, settings and timing options	2020-06-15	5/9	No	Although existing evidence suggests there is heterogeneity in the secondary attack rate of COVID-19 within households, compared to other contacts, individuals living with a positive COVID-19 case are at greater risk of infection	No	Full review	Other	Shah K, Saxena D, Mavalankar D. Secondary attack rate of COVID-19 in household contacts: Systematic review. QJM. 2020;hcaa232.
			2020-05-01	6/11	No	The incidence of positive RT-PCR and abnormal computed tomography tests were higher than 92% among pregnant women with SARS-CoV-2 infection, and fever and cough were the most common symptoms	No	Full review	Other	Uygun-Can B & Acar-Bolat B. Clinical properties and diagnostic methods of COVID-19 infection in pregnancies: Meta-analysis. BioMed Research International. 2020.
			2020-04-24	7/9	No	In patients with COVID-19, RT-PCR was found to have higher positivity rates in the early days after symptom onset, whereas sampling 10 days after symptom onset appears to substantially reduce positivity rates [Review of studies of low quality]	No	Full review	Test accuracy	Mallett S, Allen AJ, Graziadio S, Taylor SA, Sakai NS, Green K, et al. At what times during infection is SARS-CoV-2 detectable and no longer detectable using RT-PCR-based tests? A systematic review of individual participant data. BMC Medicine. 2020;18(1):346.
		Methods used in the test	2020-04-01	8/11	No	[All tests] RT-PCR using sputum samples is the most sensitive method to diagnose COVID-19, followed by the use of CT scan, with a general observation that respiratory samples are more sensitive regardless of the analysis technique used	No	Full review	Test accuracy	Böger B, Fachi MM, Vilhena RO, Cobre AF, Tonin FS, Pontarolo R. Systematic review with meta-analysis of the accuracy of diagnostic tests for COVID-19 [published online ahead of print, 2020 Jul 10]. Am J Infect Control. 2020;S0196-6553(20)30693-3. doi:10.1016/j.ajic.2020.07.011
			2020-09-30	9/11	No	[CT scan] While important heterogeneity among studies was found, available evidence suggests that chest CT scan is sensitive but has moderate specificity, which was found to be higher low prevalence settings [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Full review	Test accuracy	Islam N, Ebrahimzadeh S, Salameh J-P, Kazi S, Fabiano N, Treanor L et al. Thoracic imaging tests for the diagnosis of COVID‐19. Cochrane Database of Systematic Reviews. 2021;9:Art. No.: CD013639. DOI: 10.1002/14651858.CD013639.pub4.
			2020-05-19	9/11	No	[CT scan] The pooled sensitivity of CT scan for identifying COVID-19 infections was estimated to be 82%, although specificity was found to be higher than expected in low prevalence settings [Review of studies of variable quality]	No	Full review	Test accuracy	Bellini D, Panvini N, Carbone I, Rengo M, Wang CL, Mileto A. Diagnostic yield of computed tomography for the identification of coronavirus disease 2019 using repeated reverse transcriptase polymerase chain reaction testing or confirmed true-negative state as reference standard: Systematic review and meta-analysis. Journal of Computer Assisted Tomography. 2020;44(6):812-820.
			2020-04-25	6/11	No	[Lung ultrasound] Lung ultrasound can be a contributor to diagnosing COVID-19, but not to confidently rule out the disease	No	Full review	Test accuracy	Mohamed MFH, Al-Shokri S, Yousaf Z, et al. Frequency of Abnormalities Detected by Point-of-Care Lung Ultrasound in Symptomatic COVID-19 Patients: Systematic Review and Meta-Analysis. Am J Trop Med Hyg. 2020.
			2020-09-30	9/11	No	[Lung ultrasound] While important heterogeneity among studies was found, available evidence suggests that lung ultrasound is moderately sensitive but has very low specificity [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Full review	Test accuracy	Islam N, Ebrahimzadeh S, Salameh J-P, Kazi S, Fabiano N, Treanor L et al. Thoracic imaging tests for the diagnosis of COVID‐19. Cochrane Database of Systematic Reviews. 2021;9:Art. No.: CD013639. DOI: 10.1002/14651858.CD013639.pub4.
			2020-09-30	6/10	No	[PET/CT] PET/CT with 2-[(18)F]FDG as a radiopharmaceutical appears to have limited utility to diagnose COVID-19 compared with high resolution CT. It may have a role in detecting incidental lesions suspicious of COVID when used for other indications.	No	Full review	Other	Annunziata S, Bolton RCD, Kamani CH, Prior JO, Albano D, Bertagna F, et al. Role of 2-[(18)F]FDG as a radiopharmaceutical for PET/CT in patients with COVID-19: A systematic review. Pharmaceuticals. 2020;13(11):E377.
			2020-07-17	8/10	Yes	[RT-PCR] The false-negative (patients incorrectly diagnosed as not having COVID-19) rate of patients undergoing RT-PCR tests is uncertain, hence repeat testing is necessary where the diagnosis is in doubt	Yes (row content last updated on 2021-04-12)	Full review	Test accuracy	Arevalo-Rodriguez I, Buitrago-Garcia D, Simancas-Racines D, Zambrano-Achig P, del Campo R, Ciapponi A. False-Negative Results of Initial RT-PCR Assays for COVID-19: A Systematic Review. MedRxiv 2020.
			2020-09-30	9/11	No	[X-ray] While important heterogeneity among studies was found, available evidence suggests that lung ultrasound is moderately sensitive but has low specificity [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Full review	Test accuracy	Islam N, Ebrahimzadeh S, Salameh J-P, Kazi S, Fabiano N, Treanor L et al. Thoracic imaging tests for the diagnosis of COVID‐19. Cochrane Database of Systematic Reviews. 2021;9:Art. No.: CD013639. DOI: 10.1002/14651858.CD013639.pub4.
		Methods (type of specimen)	2020-04-30	8/11	No	The diagnostic accuracy of serological tests for COVID-19 is uncertain	No	Full review	Test accuracy	Lisboa Bastos M, Tavaziva G, Abidi SK, Campbell JR, Haraoui LP, Johnston JC, et al. Diagnostic accuracy of serological tests for covid-19: Systematic review and meta-analysis. BMJ. 2020.
			2020-04-25	7/11	No	The sensitivity of saliva-based tests is comparable to nasopharyngeal-swab tests, but there was very limited data on specificity	No	Full review	Test accuracy	Czumbel LM, Kiss S, Farkas N, Mandel I, Hegyi AE, Nagy AK, et al. Saliva as a candidate for COVID-19 diagnostic testing: A meta-analysis. medRxiv. 2020.
			2020-05-02	8/11	No	Although the sensitivity of serologic-based to detect either present or past infection are around 80%, its performance is still highly dependant on the prevalence of COVID-19	No	Full review	Test accuracy	de Moura DTH, McCarty TR, Ribeiro IB, Funari MP, de Oliveira PVAG, de Miranda Neto AA, et al. Diagnostic characteristics of serological-based COVID-19 testing: A systematic review and meta-analysis. Clinics. 2020;75:e2212.
			2020-09-10	7/9	No	Evidence suggests a relationship between the time from collection of a specimen, copy threshold, and symptom severity when doing SARS-CoV-2 culture, and also suggests that a positive PCR test in isolation may not imply infectivity [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Full review	Other	Jefferson T, Spencer E, Brassey J, Heneghan C, et al. Viral cultures for COVID-19 infectivity assessment. Systematic review. medRxiv 2020.
			2020-05-07	8/10	No	While important variation in the diagnostic accuracy of serological tests for COVID-19 was found, IgA and/or IgG based chemoluminiscense immunoassays was the most accurated followed by ELISA [Review of studies mainly of low quality]	No	Full review	Test accuracy	Mekonnen D, Mengist HM, Derbie A, Nibret E, Munshea A, He H, et al. Diagnostic accuracy of serological tests and kinetics of severe acute respiratory syndrome coronavirus 2 antibody: A systematic review and meta-analysis. Reviews in Medical Virology. 2020;e2181.
			2020-08-31	8/11	No	Pooled analyses suggest the sensitivity of PCR tests is imperfect when based on respiratory samples (although RT-PCR was found to be more sensitive than other PCRs) although specificity has been found to be consistently high [Review of studies including COVID-19 and other coronaviruses]	No	Full review	Test accuracy	Hellou MM, Górska A, Mazzaferri F, Cremonini E, Gentilotti E, De Nardo P, et al. Nucleic-acid-amplification tests from respiratory samples for the diagnosis of coronavirus infections: Systematic review and meta-analysis. Clinical Microbiology and Infection. 2020.
			2020-06-01	9/11	No	Among serological tests detecting antibodies to diagnose COVID-19, detection of IgM+ or IgG+ had the highest sensitivity, while all the panels studied had favourable specificity, and diagnostic accuracy improved in serological tests conducted 2 weeks after symptom onset [Review of studies of variable quality]	No	Full review	Test accuracy	Chen M, Qin R, Mei J, Yang Z, Wen W, Li J. Clinical applications of detecting IgG, IgM, or IgA antibody for the diagnosis of COVID-19: A meta-analysis and systematic review. International Journal of Infectious Diseases. 2021.
		Methods (site from where specimen is taken)	2020-04-01	8/11	No	RT-PCR using sputum samples is the most sensitive method to diagnose COVID-19, followed by the use of CT scan, with a general observation that respiratory samples are more sensitive regardless of the analysis technique used	No	Full review	Test accuracy	Böger B, Fachi MM, Vilhena RO, Cobre AF, Tonin FS, Pontarolo R. Systematic review with meta-analysis of the accuracy of diagnostic tests for COVID-19 [published online ahead of print, 2020 Jul 10]. Am J Infect Control. 2020;S0196-6553(20)30693-3. doi:10.1016/j.ajic.2020.07.011
			2020-05-04	4/10	No	[All tests] The body part sampled and timing of test relative to symptom onset might influence the accuracy of RT-PCR tests, but there is a lack of studies evaluating the test accuracy of RT-PCR [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Rapid review	Test accuracy	Health Technology Wales. The clinical effectiveness of tests to detect the presence of SARS-CoV-2 virus, and antibodies to SARS-CoV-2, to inform COVID-19 diagnosis. Cardiff, UK: Health Technology Wales, 2020.
			2020-04-19	7/10	No	In children with SARS-CoV-2 infection, viral shedding samples have been found to be present for longer in feces compared to the respiratory tract. This may be of relevance in relation to different possible routes of transmission.	No	Full review	Other	Santos VS, Gurgel RQ, Cuevas LE, Martins-Filho PR. Prolonged fecal shedding of SARS-CoV-2 in pediatric patients. A quantitative evidence synthesis [published online ahead of print, 2020 May 22]. J Pediatr Gastroenterol Nutr. 2020;10.1097/MPG.0000000000002798. doi:10.1097/MPG.0000000000002798
			Not specified	8/11	No	In people with severe acute respiratory syndrome caused by SARS-Cov-2, lower respiratory tract samples (especially bronchoalveolar lavaga fluid) and rectal specimens were the most likely to test positive, whereas nasopharyngeal swabs had a positive rate of less then 50% and the virus was not detected in urogenital specimens using RT PCR	No	Full review	Other	Bwire GM, Majigo MV, Njiro BJ, Mawazo A. Detection profile of SARS-CoV-2 using RT-PCR in different types of clinical specimens: A systematic review and meta-analysis. Journal of medical virology. 2020.
			2020-04-30	6/10	No	The likelihood of a positive SARS-CoV-2 test using a respiratory sample decreases with time from symptoms onset, with sputum specimens showing the highest positivity rates, and oropharyngeal swabs the lowest	No	Full review	Other	Mohammadi A, Esmaeilzadeh E, Li Y, Bosch RJ, Li J. SARS-CoV-2 detection in different respiratory sites: A systematic review and meta-analysis. Medrxiv. 2020.
			Not specified	8/11	No	Lower respiratory tract specimens appear to be best for detecting SARS-CoV-2 infection, with bronchalveolar lavage fluids offering the highest positivity rate, whereas the virus can also be detected to varying degrees of success using rectal swabs, sputum, nasopharyngeal and oropharyngeal swabs, but cannot be detected successfully from urinogenital samples	No	Full review	Other	Bwire GM, Majigo MV, Njiro BJ, Mawazo A. Profiling the positive detection rate of SARS-CoV-2 using polymerase chain reaction in different types of clinical specimens: A systematic review and meta-analysis. medRxiv. 2020.
			2020-06-01	7/11	No	Low prevalence of ocular manifestations of COVID-19 was found and a very low PCR positivity rate on ocular samples [Review of observational studies]	No	Full review	Test accuracy	La Distia Nora R, Putera I, Khalisha DF, Septiana I, Ridwan AS, Sitompul R. Are eyes the windows to COVID-19? Systematic review and meta-analysis. BMJ Open Ophthalmology. 2020;5(1).
			2020-08-10	7/11	No	Fecal viral nucleic acid was present in a high number of children with COVID-19, although the characteristics of patients having stool samples positive for viral nucleic acid with symptom resolution remains uncertain [Review of studies of unknown quality]	No	Full review	Other	Wang JG, Cui HR, Tang HB, Deng XL Gastrointestinal symptoms and fecal nucleic acid testing of children with 2019 coronavirus disease: A systematic review and meta-analysis. Scientific Reports. 2020;10(1):17846.
			2020-11-01	7/11	No	No important differences were found on the sensitivity of testing for SARS-CoV-2 infection with saliva versus nasopharyngeal swabs, although the results substantially change depending on the method of saliva collection [Review of observational studies of variable quality]	No	Full review	Test accuracy	Bastos ML, Perlman-Arrow S, Menzies D, Campbell JR. The sensitivity and costs of testing for SARS-CoV-2 infection with saliva versus nasopharyngeal swabs: A systematic review and meta-analysis. Annals of Internal Medicine. 2021.
		Speeding results	2020-05-25	9/11	No	Important heterogeneity in the diagnostic accuracy of point-of-care antigen and molecular tests to diagnose SARS-CoV-2 infection was found [Review mainly based on low or unclear quality studies]	Yes (row content last updated on 2021-04-12)	Full review	Test accuracy	Dinnes J, Deeks JJ, Adriano A, Berhane S, Davenport C, Dittrich S, et al. Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection. Cochrane Database of Systematic Reviews. 2020;(8):Art. No.: CD013705. DOI: 10.1002/14651858.CD013705.
			2020-06-27	4/9	No	Machine learning techniques to analyze chest CT and X-ray images might be able to accurately detect the presence of COVID-19 [Review mainly based on studies of unknown quality]	No	Full review	Other	Syeda HB, Syed M, Sexton KW, et al. The Role of Machine Learning Techniques to Tackle COVID-19 Crisis: A Systematic Review. medRxiv 2020.
			2020-09-28	9/11	No	The majority of isothermal nucleic acid point-of-care tests have reported at least 90% sensitivity and specificity, but the diagnostic accuracy increased in samples with medium to high viral load, without needing a RNA sample purification step [Review of studies mainly of low quality conducted during COVID-19 and other coronaviruses outbreaks]	No	Full review	Test accuracy	Subsoontorn P, Lohitnavy M, Kongkaew C. The diagnostic accuracy of isothermal nucleic acid point-of-care tests for human coronaviruses: A systematic review and meta-analysis. Scientific Reports. 2020;10(1):22349.
			2020-08-10	8/11	No	Point-of-care testing using molecular assays offer 94% sensitivity and very high specificity in the detection of SARS-CoV-2 [Review of studies of variable quality and high heterogeneity]	No	Full review	Test accuracy	Yoon SH, Yang S, Cho H, Eun S, Koo CM, Kim MK. Point-of-care testing for the detection of SARS-CoV-2: A systematic review and meta-analysis. European Review for Medical and Pharmacological Sciences. 2021;25(1):503-517.
			2020-11-20	5/11	No	Only two rapid-antigen tests (Roche/SDB and Abbott) were found to provide enough real-world performance data to confirm that they are able to detect current SARS-CoV-2 infection [Review of studies of unknown quality]	No	Full review	Test accuracy	Hayer J, Kasapic D, Zemmrich CS. Real-world clinical performance of commercial SARS-CoV-2 rapid antigen tests in suspected COVID-19: A systematic meta-analysis of available data as per November 20, 2020. medRxiv. 2020.
	Isolation of suspected or confirmed cases		2020-08-26	6/10	No	COVID-19 patients with mild-to-moderate illness are unlikely to be infectious after 10 days from symptom onset, whereas severe or immunocompromised patients may remain infectious for longer than 10 days [Review including studies of variable quality]	No	Full review	Other	Walsh KA, Spillane S, Comber L, Cardwell K, Harrington P, Connell J, et al. The duration of infectiousness of individuals infected with SARS-CoV-2. Journal of Infection. 2020.
			2020-06-22	8/11	No	The proportion of asymptomatic infections among COVID-19 patients was found to be high, and results indicate asymptomatic patients have substantial transmission potential [Review of studies of mainly low quality]	No	Full review	Other	Yanes-Lane M, Winters N, Fregonese F, Bastos M, Perlman-Arrow S, Campbell JR, et al. Proportion of asymptomatic infection among COVID-19 positive persons and their transmission potential: A systematic review and meta-analysis. PLoS One. 2020;15(11):e0241536.
			N/A (protocol)	n/a	Yes	[Protocol - results not yet available] A systematic review exploring behaviour-management strategies to aid self-isolation for unwilling and unable individuals during the COVID-19 pandemic is currently being conducted	No	Protocol	Other	Bahji A, Crockford D. Behaviour management strategies to aid self-isolation for unwilling and unable individuals during the COVID-19 pandemic: a systematic review. PROSPERO. 2020;CRD42020208155.
	Contact tracing		2020-05-05	10/10	Yes	Digital contact tracing technologies used alongside manual methods and other public-health measures such as isolation may successfully identify secondary cases and could save time, but there is limited evidence about their effectiveness, acceptability and implementation in real-world outbreak settings	No	Rapid review	Benefits and harms	Anglemyer A, Moore THM, Parker L, Chambers T, Grady A, Chiu K, et al. Digital contact tracing technologies in epidemics: A rapid review. Cochrane Database of Systematic Reviews 2020, Issue 8. Art. No.: CD013699. DOI: 10.1002/14651858.CD013699
			2020-04-30	6/9	No	A systematic review found no empirical studies comparing automated with manual contact tracing systems for COVID-19 or other infectious diseases, but modelling studies suggest that the effectiveness of contact tracing depends on disease context, timeliness of case identification and notification, tracers' expertise, case and contact definitions, and behavioral factors	No	Full review	Benefits and harms	Braithwaite I, Callender T, Bullock M, Aldridge RW. Automated and partly automated contact tracing: A systematic review to inform the control of COVID-19. The Lancet Digital Health. 2020;2(11):e607-e621.
			2020-07-15	9/9	No	Feelings of collective responsibility motivate people to engage in contact-tracing systems, but this motivating factor must outweigh privacy concerns, mistrust of government or public-health officials and be reinforced by clear and consistent information about the personal and collective benefits of these systems [Review of studies conducted during COVID-19, Ebola and other outbreaks]	No	Rapid review	Other	Megnin-Viggars O, Carter P, Melendez-Torres GJ, Weston D, Rubin GJ. Facilitators and barriers to engagement with contact tracing during infectious disease outbreaks: A rapid review of the evidence. PLoS One. 2020;15(10):e0241473.
	Susceptibility tracking
		Antibody testing	2020-05-01	7/9	No	Existing studies suggest urgency to examine seroprevalence may have compromised methodological rigour, restricting the conclusions that can be drawn about the link between prevalence and immunity to COVID-19	Yes (row content last updated on 2021-04-12)	Rapid review	Other	Bobrovitz N, Arora R, Yan T, Rahim H, Duarte N, Bouher E, et al. Lessons from a Rapid Systematic Review of Early SARS-CoV-2 Serosurveys. MedRxiv 2020.
			2020-04-27	11/11	No	Antibody testing appears to be a potentially appropriate approach for detecting previous SARS-CoV-2 infection when taken 15 days after symptom onset, with uncertainty remaining about their application beyond 35 days after symptom onset	No	Full review	Test accuracy	Deeks JJ, Dinnes J, Takwoingi Y, Davenport C, Spijker R, Taylor-Phillips S, et al. Antibody tests for identification of current and past infection with SARS-CoV-2. Cochrane Database Syst Rev. 2020 Jun 25;
			2020-07-06	5/9	No	The immunity response following infection with COVID-19 is not yet known, the presence of antibody response was consistently reported, but the probability of reinfection can't be ruled out	Yes (row content last updated on 2021-04-12)	Full review	Other	Health Information and Quality Authority, Ireland. Evidence summary of immunity response following infection with COVID-19. Cork, Ireland: Health Information and Quality Authority, Ireland; 2020.
			2020-08-14	7/11	No	A meta-analysis showed that pooled global SARS-CoV-2 seroprevalence varied substantially across regions and countries (between 0.37% and 22.1%)	No	Full review	Other	Rostami A, Sepidarkish M, Leeflang M, Riahi SM, Shiadeh MN, Esfandyari S, et al. First snap-shot meta-analysis to estimate the prevalence of serum antibodies to SARS-CoV-2 in humans. medRxiv. 2020.
			2020-04-04	9/11	Yes	FDA authorized serology tests to detect SARS-CoV-2 antibodies probably have a high sensitivity and specificity, but their diagnostic accuracy is optimal 15 or more days post symptom onset	No	Full review	Test accuracy	Rajesh P & Anand G. Diagnostic accuracy of FDA authorized serology tests to detect SARS-CoV-2 antibodies: A systematic review and meta-analysis. medRxiv. 2020.
			2020-09-18	7/9	No	The potential for COVID-19 re-infection and for new transmission after recovery is currently uncertain	Yes (row content last updated on 2021-04-12)	Rapid review	Other	National Collaborating Centre for Methods and Tools. Rapid Review Update 3: What is known on the potential for COVID-19 re-infection, including new transmission after recovery? Hamilton, ON: National Collaborating Centre for Methods and Tools; 2020.
			2020-05-04	4/10	No	Extensive variability in the sensitivity estimates across tests used to detect antibodies to SARS-CoV-2 was found [Review mainly based on low quality studies]	Yes (row content last updated on 2021-04-12)	Rapid review	Test accuracy	Health Technology Wales. The clinical effectiveness of tests to detect the presence of SARS-CoV-2 virus, and antibodies to SARS-CoV-2, to inform COVID-19 diagnosis. Cardiff, UK: Health Technology Wales, 2020.
		Antibody test usage	2020-04-03	4/9	No	No evidence was found to inform clinical or public-health implications of serological antibody testing as priority indications for COVID-19 [Review of observational studies mainly of low quality]	No	Rapid review	Other	Alberta Health Services, COVID-19 Scientific Advisory Group. Priority indications for serologic testing for COVID-19 rapid review. Alberta: Alberta Health Services, COVID-19 Scientific Advisory Group; 2020
Broader public-health measures
	Risk stratification
		Stratifying the population by risk of infection	2020-06-15	5/9	No	Although existing evidence suggests there is heterogeneity in the secondary attack rate of COVID-19 within households, compared to other contacts, individuals living with a positive COVID-19 care are at greater risk of infection	No	Full review	Other	Shah K, Saxena D, Mavalankar D. Secondary attack rate of COVID-19 in household contacts: Systematic review. QJM. 2020;hcaa232.
			N/A (Protocol)	n/a	No	[Protocol - results not yet available] A systematic review to explore the association between demographic factors and a COVID-19 diagnosis in patients is currently being conducted	Yes (row content last updated on 2020-12-07)	Protocol	Other	Atherley A, Derckx R, Dijkstra J, Franssen G, Hendriks S, Jolani S, et al. Demographic Factors and COVID-19: a Rapid and Living Systematic Review and Meta-Analysis. PROSPERO 2020; CRD42020180085.
			N/A (Protocol)	n/a	No	[Protocol - results not yet available] A systematic review to explore the association between lifestyle factors and a COVID-19 diagnosis is currently being conducted	Yes (row content last updated on 2020-12-07)	Protocol	Other	Wesselius A, der Ven E, Bongaerts B, Dijksma I, Ament S, Falahi F, et al. Lifestyle Factors and COVID-19: a Rapid and Living Systematic Review and Meta-Analysis. PROSPERO 2020; CRD42020181902.
			2020-07-08	7/11	No	Healthcare workers, particularly nurses, report a high prevalence of SARS-CoV-2 infection, with a significant proportion of asymptomatic or pre-symptomatic carriers	Yes (row content last updated on 2021-04-12)	Full review	Other	Gómez-Ochoa SA, Franco OH, Rojas LZ, Raguindin PF, Roa-Diaz ZM, Wyssmann BM, et al. COVID-19 in healthcare workers: A living systematic review and meta-analysis of prevalence, risk factors, clinical characteristics, and outcomes. American Journal of Epidemiology. 2020.
			2021-02-16	6/11	No	The relationship between smoking status and infection, hospitalisation and mortality is uncertain. Current smokers may be at reduced risk of infection compared with non smokers, but they and former smokers may have an increased risk of hospitalisation and greater disease severity [Review of observational studies]	Yes (row content last updated on 2021-04-12)	Rapid review	Other	Simons D, Shahab L, Brown J, Perski O. The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from COVID-19: A living rapid evidence review with Bayesian meta-analyses (version 11). Addiction. 2021.
			2020-07-25	7/11	No	Secondary attack rates averaged at about 18% with substantial heterogeneity, with higher rates in households and other residential settings and when infections are symptomatic [Review of observational studies]	No	Full review	Other	Koh WC, Naing L, Chaw L, Rosledzana MA, Alikhan MF, Jamaludin SA, et al. What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors. medRxiv. 2020;15(10):e0240205.
			2020-06-10	5/9	No	Some evidence shows that children with COVID-19 appear more likely to be asymptomatic, and adult to child transmission seems to be less likely than child to child or child to adult transmissions [Review of studies of unknown quality]	Yes (row content last updated on 2021-04-12)	Rapid review	Other	COVID-19 Scientific Advisory Group. What role might children play in community SARS-CoV-2 transmission? What measures might mitigate potential additional risk of transmission of COVID-19 related to school and daycare reopening? Calgary, AB: Alberta Health Services; 2020.
	Outbreak management
		Locations (essential services or other)	2020-06-26	7/10	Yes	Outbreak investigations show that long-term care facilities are more vulnerable to the COVID-19 pandemic, in terms of disease spread and mortality rate	Yes (row content last updated on 2021-04-12)	Full review	Other	Salcher-Konrad M, Jhass A, Naci H, Tan M, El-Tawil Y, Comas-Herrera A. COVID-19 Related Mortality and Spread of Disease in Long-Term Care: First Findings from a Living Systematic Review of Emerging Evidence. MedRxiv 2020.
			2021-02-01	7/10	Yes	Implementation of a comprehensive COVID-19 plan, with strategies to prevent introduction of COVID-19 into long-term care facilities, identify and isolate cases, decrease likelihood of transmission and provide high-quality medical care to residents, may be effective to reduce both viral transmission and mortality within-long term care homes	Yes (row content last updated on 2021-04-12)	Rapid review	Other	National Collaborating Centre for Methods and Tools. Rapid review update 2: What risk factors are associated with COVID-19 outbreaks and mortality in long-term care facilities and what strategies mitigate risk? National Collaborating Centre for Methods and Tools. 2021;
	Pandemic tracking
		Levels of re-emergence that trigger action

* This topic has been the focus of extensive academic debate (see here), and the evidence is frequently being updated

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