Summary: For health care personnel working near patients during the peak season for viral respiratory illnesses use of routine medical masks may be associated with the same risk of developing laboratory confirmed influenza, acute respiratory illness, or influenza-like illness as use of N95 respirators; while standard medical masks are both simpler to use and less costly than N95 respirators.

https://www.ncbi.nlm.nih.gov/m/pubmed/31479137/

Strength of Recommendation = B