According to the World Health Organization’s June 5, 2020, guidance on face mask use, there’s no direct evidence that universal masking of healthy people is an effective intervention against respiratory illnesses
While masks do not prevent the spread of viral infections, the WHO still makes a case for universal mask-wearing, citing benefits such as reduced stigmatization of people caring for COVID-19 patients in nonclinical settings, making people feel like they’re doing something to help, serving as a reminder to be compliant with other measures, and economic benefits for people who can sew homemade masks
Despite the fact that cloth masks are far less effective for blocking potentially infectious respiratory droplets, the WHO recommends cloth masks should be worn by infected persons in community settings
A policy review paper published in the CDC’s journal Emerging Infectious Diseases found that masks did not protect against influenza in non-healthcare settings
Harms and risks of mask-wearing include health effects associated with poor air quality and toxic ingredients in the mask, self-contamination caused by manipulation of the mask by contaminated hands, general discomfort, facial skin lesions, irritant dermatitis or worsening acne, and a false sense of security that may reduce adherence to other preventive measures such as hand hygiene
"At present, there is no direct evidence (from studies on COVID- 19 and in healthy people in the community) on the effectiveness of universal masking of healthy people in the community to prevent infection with respiratory viruses, including COVID-19."