A rapid review report published by the UK Health Security Agency (UKHSA) investigated if high-quality masks, such as the N95, KN95 and FFP2 coverings, protect clinically vulnerable people in the community from catching Covid.
However, the report was unable to find a single piece of scientific research which had usable data.
“The review did not identify any studies for inclusion, and so could provide no evidence to answer the research question,” the authors state. “No studies matching the inclusion criteria were found, so no evidence could be presented.”