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Evidence about public-health measures (under construction)

 

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
Date of last search Quality (AMSTAR) rating Evidence profile (e.g., GRADE) available              Key findings
Living evidence synthesis Type of synthesis              Type of question
Infection prevention                
  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 9/11 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 2020-08-13)
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
    2020-04-01  9/10  No Limited evidence from trials focused on influenza and influenza-like-illness indicates that there is uncertainty about the benefits of mask wearing among the general population compared to no masks, or between different types of masks
 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.
      2020-05-18
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. 
    Wearing personal protective equipment 2020-05-03  9/11  Yes No direct evidence is available regarding the effect of wearing masks for prevention of COVID-19 in community settings, and inconsistent findings have been found in studies conducted for other respiratory infections Yes (row content last updated on 2020-09-02) 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
    2020-06-02
7/10  No  Low certainty evidence suggests N95 respirators and eye protection can lead to a reduction in viral infections
Yes (row content last updated on 2020-08-13)  Rapid review  Benefits and harms
Chou R, Dana T, Jungbauer R, Weeks C, McDonagh MS. Masks for prevention of COVID-19 in community and healthcare settings: A living rapid review. Annals of internal medicine. 2020;M20-3213.  
    2020-04-24 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 2020-08-13) Full review Benefits and harms  Chou R, Dana T, Buckley D, Selph S, Fu R, Totten A. Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers. Ann Intern Med 2020; M20-1632
    2020-04-01 9/10 No Evidence from existing trials has not found a statistically significant difference in reductions of influenza-like-illness or influenza cases when mask wearing is compared compared to no masks among healthcare workers
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.
      2020-04-08
8/10  No The safety of different decontamination methods for reusing surgical masks in clinical settings is uncertain
Yes (row content last updated on 2020-08-13)  Full review How and why it works 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.
    Disinfecting surfaces and facilities                
    Physical distancing 2020-05-03 9/11 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 2020-08-13) 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
      2020-05-08
7/9  No  Synthesis pending
Yes (row content last updated on 2020-09-02)  Full review  Benefits and harms  COVID NMA. Social Distancing at Sports Training vs No Access to Sports Training Facilities. 2020. 
    Temporal distancing                
    Public-focused behaviour-change supports 2020-05-01
6/11 No Evidence from single-arm observational studies show that 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 the authors conclude requires extensive behaviour intervention and community awareness 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. 
    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.
  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 2020-08-13)  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
8/10  No  No evidence is available regarding symptoms that can be used to determine if patients presenting to primary care have COVID-19, and evidence for patients presenting to outpatient clinics and emergency departments suggests there are no clear set of symptoms that can be used to indicate a COVID-19 infection
Yes (row content last updated on 2020-09-03)
Full review Benefits and harms  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 
    Methods  2020-04-21
6/11  No  Most cases of COVID-19 in children have a favourable clinical course, and the most prevalent clinical manifestations of COVID-19 are fever, cough, nasal symptoms, diarrhea, and nausea/vomiting, which should not be considered a hallmark of infection
No  Full review  Other  Ma X, Liu S, Chen L, Zhuang L, Zhang J, Xin Y. The clinical characteristics of pediatric inpatients with SARS-CoV-2 infection: a meta-analysis and systematic review [published online ahead of print, 2020 Jun 19]. J Med Virol. 2020;10.1002/jmv.26208. doi:10.1002/jmv.26208 
      2020-04-11
7/11  No  Most cases of COVID-19 in children and adolescents have a favourable clinical course, with the most prevalent clinical manifestations being fever and cough  No  Full review  Other  Mantovani A, Rinaldi E, Zusi C, Beatric G, Saccomani D, Dalbeni A. Coronavirus Disease 2019 (COVID-19) in Children and/or Adolescents: A Meta-Analysis. Pediatr Res 2020. 
      2020-04-30
9/11  No  A review of observational studies found evidence that children over 12 months of age generally experience milder symptoms than adults, but that younger children were more likely to experience critical illness and vomiting 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. 
    Locations (and frequency if applicable)                
  Quarantining of exposed or potentially exposed individuals                
    Voluntary or imposed 2020-04-01 9/10 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.
  Testing                
    Priority individuals (including their contacts) 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. 
    Methods (including performance and quality assurance)
2020-04-01  8/10  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 
      2020-04-27
11/11  No  [Antibody testing] Antibody testing may be an 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;  
      2020-06-07  7/10  Yes  [CT scan] The sensitivity of using chest computed tomography to diagnose SARS-CoV-2 infection was found to be similar to using RT-PCR, particularly in symptomatic patients, but there is a lack of evidence about its use for diagnosing asymptomatic patients
No Full review  Test accuracy  Shao, J.M., Ayuso, S.A., Deerenberg, E.B., Elhage, S.A., Augenstein, V. and Heniford, B.T. (2020), A Systematic Review of CT Chest in COVID‐19 Diagnosis and its Potential Application in a Surgical Setting. Colorectal Dis. Accepted Author Manuscript. doi:10.1111/codi.15252 
      2020-04-03
7/11  No  [CT scan] Whilst the sensitivity of both chest CT and reverse transcriptase PCR were both high, the pooled specificity for chest CT was only 37%. Hence the use of CT scan as a screening tool to identify patients with COVID-19 is substantially impaired, particularly in low prevalence regions No  Full review  Other  Kim H, Hong H, Yoon S. Diagnostic performance of CT and reverse transcriptase-polymerase chain reaction for Coronavirus Disease 2019: A meta-analysis. Radiology. 2020. 
      2020-04-23
7/11  No  [CT scan] A review of mostly retrospective cohort studies found that vascular enlargement sign detected using a chest computed tomography has been shown to be to be present in a large proportion of patients with COVID-19, which could be helpful in identifying pneumonia caused by infection No  Full review  Other  Lv H, Chen T, Pan Y, Wang H, Chen L, Lu Y. Pulmonary vascular enlargement on thoracic CT for diagnosis and differential diagnosis of COVID-19: A systematic review and meta-analysis. Annals of translational medicine. 2020;8(14):878. 
      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.  
   
2020-04-06 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 2020-08-13) Full review Other 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.
      2020-04-03
7/11  No  [RT-PCR] The sensitivity of using RT-PCR to diagnose SARS-CoV-2 infection is estimated at 89%, and while the positive predictive value is 10 times higher than using CT scan, repeat testing is probably necessary where the diagnosis is in doubt No  Full review Other  Kim H, Hong H, Yoon S. Diagnostic performance of CT and reverse transcriptase-polymerase chain reaction for Coronavirus Disease 2019: A meta-analysis. Radiology. 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 
      2020-05-11
6/11 No The level of viral RNA detected in blood samples taken from COVID-19 patients appears too low to be infectious and is unlikely to pose a threat to individuals handling the samples  No Full review Other Andersson M, Arancibia-Carcamo C, Auckland K, Baillie K, Barnes E, Beneke T. SARS-CoV-2 RNA Detected in Blood Samples from Patients with COVID-19 is Not Associated with Infectious Virus. MedRxivi 2020. 
      2020-04-30
8/11  No  The diagnostic accuracy of serological tests for COVID-19 is uncertain  No Full review Benefits and harms  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
7/10  No  The sensitivity of saliva-based tests is comparable to nasopharyngeal-swab tests, but there was very limited data on specificity
No  Full review  Other  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  Other  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. 
    Locations (and frequency if applicable)                
    Speeding results 2020-04-13
8/11 No There is no strong evidence to accurately indicate the sensitivity and specificity for available rapid point-of-care COVID-19 diagnostic tests  No  Full review  Other  Ricco M, Ferraro P, Gualerzi G, et al. Point-of-Care Diagnostic Tests for Detecting SARS-CoV-2 Antibodies: A Systematic Review and Meta-Analysis of Real-World Data. J Clin Med 2020 May 18;9(5). 
      2020-05-25
9/11  No  Studies with unclear or high risk of bias showed important heterogeneity in the diagnostic accuracy of point-of-care antigen and molecular tests to diagnose SARS-CoV-2 infection Yes (row content last updated on 2020-09-29)  Full review  Other  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. 
  Isolation of suspected or confirmed cases 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. 
  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 
  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 2020-08-13)  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  Other  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 2020-09-03) 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. 
    Antibody test usage                
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. 
  Outbreak management                
    Locations (essential services or other) 2020-05-29 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 2020-08-13) 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.
  Pandemic tracking                
    Levels of re-emergence that trigger action                
  Vaccination                
    Vaccines to prevent other infections                
Future possible public-health measures                
  Vaccination (susceptibility reduction)                
    Supporting discovery of a vaccine to prevent COVID-19 (followed by its production, distribution, administration)                
    Choosing the best available vaccine to prevent COVID-19
               

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

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