Two current trends in the U.S. disturb me. (1) Science denial is worn by some as a badge of honor, rather than shame. (2) Opinions held by some people are believed to be as credible as facts to those same people. It’s a quirky kind of narcissism and hubris.
To counter both trends, I offer this scientific journal article. It is not a single study. Rather, it is a meta-analysis that reviewed 172 observational studies in health-care and non-health-care settings across 16 countries and six continents; 44 comparative studies were included in a meta-analysis, including 25,697 patients with COVID-19, SARS, or MERS. Data trump opinions.
The researchers found that of the three prevention techniques — physical distance, face mask vs. no face mask, eye protection — mask use led to the highest reduction of virus transmission. Masks reduced person-to-person transmission in the range of 10.7% to 15.9%. Distances over 1 meter (39 inches) ranged from 7.5% to 11.5%; eye protection reductions ranged between 7.7% and 12.5%.
Thus, masks provided the best protection. The authors of the study considered the amount of the transmission reduction significant.
The caveat about masks is that N95 respirators might be associated with a larger reduction in risk compared with surgical or similar masks.
The summary of the lessons from the 172 studies was published in the The Lancet. The Lancet is a world leading medical journal established in 1823. It has a Journal Impact Factor of 60.392® (2019 Journal Citation Reports®, Clarivate Analytics 2020) and is currently ranked second out of 160 journals in the Medicine, General & Internal subject category. It is not a source of disinformation that thrives on FB.
Chu, D.K., et al. (2020) Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis. The Lancet, Vol. 395, June 27, 2020. Download and read the article.
