What is known about strategies for supporting the use of masks under shortage conditions to prevent COVID-19?

We identified 50 documents that provide highly relevant evidence to answer the question in relation to six areas, including: 1) producing (home-based production, rapid technological innovations, and fast tracking regulatory processes); 2) allocating (efficient allocation and stocking practices); 3) using masks (e.g., support for correct use and monitoring for correct use); 4) conserving masks (use beyond the recommended duration and use beyond the recommended shelf life); 5) re-using masks (re-using by the same person without decontaminating, decontaminating and reusing by the same person, and decontaminating and reusing by others); and 6) re-purposing masks (medical masks and alternative materials).