Infection prevention and controlin the context of coronavirus disease … – World Health Organization

The Infection prevention and control in the context of coronavirus disease 2019 (COVID-19): a living guideline consolidates infection prevention and control (IPC) technical guidance developed and published during the COVID-19 pandemic into evidence-informed recommendations for IPC. This living guideline is available both online and PDF. 
This version of the guidelines (version 4.0), includes the following recommendations: 
1) a strong recommendation for mask use in community settings in higher risk situations; 
2) a conditional recommendation to encourage a risk-based approach for mask use in community settings in situations that do not fall within the scope of the strong recommendation; 
3) a good practice statement advising individuals with signs and symptoms suggestive of COVID-19 or those who test positive for COVID-19 to wear a medical mask when interacting with others in or outside of one’s household or sharing space with others; and 
4) amendment of an existing good practice statement on the implementation of policies to reduce SARS-CoV-2 transmission to promote the revisiting and strengthening of PHSM as new evidence arises. 
The strong and conditional recommendations for mask use in the community complement each other, outlining possible scenarios in which masks may benefit the wearer. As some situations (see strong recommendation) necessitate mask wearing for maximum protection, others (see conditional recommendation) may be better suited for a risk-based approach.  
Updates to prior recommendations 
Version 4.0 of the living guideline is the most recent update on guidance for mask use in the community. 
This guideline supersedes the recommendations found in: