Use of facemasks and hand-hygiene & environmental cleaning measures in non-medical community setting showed no significant protective effect against transmission of laboratory confirmed Influenza. However, there are several limitations to the data used in this analysis and, coupled with the difference in infectivity of Covid -19, the results may not applicable to the current pandemic.
Xiao J, Shiu EYC, Gao H, Wong JW, Fong MW, Ryu S, et al. Nonpharmaceutical measures for pandemic influenza in nonhealthcare settings—personal protective and environmental measures. Emerg Infect Dis. 2020, 06 Feb. https://doi.org/10.3201/eid2605.190994
Article Link – EIDPrevention-Non drug-PPE use in non-healthcare settings