evidence: As of July 26, 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 16 000 000 individuals worldwide and caused over 600 000 deaths from COVID-19. Despite advances in pharmacological treatment and early vaccine development, reducing transmission of the virus with the use of facemasks (referring to medical or surgical masks, N-95 and similar respirators, cloth masks, and bandannas) by health-care workers and the public alike remains a hotly debated topic due to politicisation of discourse and decision making. [...] In summary, the current best evidence includes the possibility of important relative and absolute benefits of wearing a facemask. Depending on the pandemic situation in a given geographical setting, the desirable consequences of wearing a facemask may or may not outweigh the undesirable consequences. These considerations should influence policy makers' recommendations starting with the involvement of the relevant stakeholders. In highly populated areas that have high infection rates—eg, USA, India, Brazil, or South Africa—the use of masks will probably outweigh any potential downsides. If larger relative effects of masks are confirmed by forthcoming trials, and the entire population wants to make a contribution to reduce transmission, then a few months of universal facemask wearing would achieve a lot, but it will come at a cost. That cost might be lower than not reopening businesses and schools once baseline risk achieves acceptable levels. As no intervention is associated with affording complete protection from infection, a combination of measures will always be required, now and during the next pandemic.