Association between face mask use and risk of SARS-CoV-2 infection: Cross-sectional study

Abstract

We examined the association between face masks and risk of infection with SARS-CoV-2 using cross-sectional data from 3,209 participants in a randomized trial exploring the effectiveness of glasses in reducing the risk of SARS-CoV-2 infection. Face mask use was based on participants’ response to the end-of-follow-up survey. We found that the incidence of self-reported COVID-19 was 33% (aRR 1.33; 95% CI 1.03–1.72) higher in those wearing face masks often or sometimes, and 40% (aRR 1.40; 95% CI 1.08–1.82) higher in those wearing face masks almost always or always, compared to participants who reported wearing face masks never or almost never. We believe the observed increase in the incidence of infection associated with wearing a face mask is likely due to unobservable and hence nonadjustable differences between those wearing and not wearing a mask. Observational studies reporting on the relationship between face mask use and risk of respiratory infections should be interpreted cautiously, and more randomized trials are needed.

The Bacterial Burden of Worn Face Masks – Observational Research and Literature Review

“…In short, the adverse effects of masks are clear [2,3,5,15,17,19,20,24,37,124,[158][159][160][161][162][163][164]179], whereas the protective antiviral effect in real life scenarios remains doubtful [13][14][15][16]157,[180][181][182][183][184][185][186][187][188][189][190][191][192][193][194][195][196][197][198]. Given this, together with the microbiological contamination issues highlighted, masking laws and requirements do not meet the basic medical ethic of 'Do no harm'.…”

“…For masks to be demanded, the side effects and risks must be lower than the risk of not wearing a mask. A gold-standard Cochrane evaluation, based on clinical trials [13] found no substantive evidence of efficacy in preventing viral respiratory infections and one recent study, albeit with several possible confounders, even found mask-wearing to be associated with an increased risk of COVID-19 infection [157]. On the other hand, the potential harms are numerous [2,3,5,[15][16][17][20][21][22][23][24]37,38,[158][159][160][161][162][163][164].…”