There’s no concrete evidence yet that masks work

Joel M. Zinberg, Tribune News Service

Joe Biden proclaimed, “Wearing masks is not a political statement, it is a scientific imperative.” He was wrong. There is little evidence supporting generalized use of masks. A pre-COVID systemic review of interventions to combat the spread of respiratory viral diseases by the highly regarded Cochrane Library found that medical/surgical mask wearing makes little or no difference to the outcome of influenza or influenza-like illnesses compared to not wearing a mask. A recent review of the literature reported two randomized controlled clinical trials of the effectiveness of masking in COVID-19. One failed to demonstrate a statistically significant benefit.

The second found small, marginally statistically significant reductions in viral transmission for surgical masks but not for cloth masks. Thirteen of 14 tests assessing mask wearing in non-COVID respiratory infections failed to find a statistically significant benefit for masks. Randomized controlled clinical trials are the gold standard in medical research because randomization minimizes the effect of unmeasured confounding variables and researcher bias that can occur in observational studies.

Early in the pandemic, the Centers for Disease Control and Prevention, the World Health Organization, British health authorities and the European Center for Disease Prevention and Control all refrained from recommending widespread mask usage, often discouraging it. Dr. Anthony Fauci emailed in February 2020 that the typical mask “is not really effective in keeping out virus, which is small enough to pass through the material.” In a March 8 interview on “60 Minutes” he said that “there’s no reason to be walking around with a mask.”

Nevertheless, the CDC in April 2020 began recommending mask wearing, including cloth masks. A CDC Science Brief relied on observational masking studies where the evidence suggested benefit, while highlighting the limitations rather than outcomes of studies that suggested the absence of benefit or even harm.  Endorsing cloth masks was disconcerting since an RCT of hospital workers showed far higher infection rates with cloth masks than medical masks.

The CDC repeatedly highlighted an observational study of two COVID-positive hair stylists in Missouri who were masked and provided services for several days after developing COVID-19 symptoms to 139 customers, who were mostly masked. Sixty-seven customers who were tested were negative and none of the remaining 72 reported symptoms.

Yet, no one knows if any of the 72 untested, asymptomatic customers were actually infected. Half of COVID-19 infected people are asymptomatic or have mild symptoms. In addition, viral shedding and infectiousness is highest in the two to three days before symptom onset, which is before these symptomatic hairdressers encountered the study customers. Finally, there was no control group to show how many customers would be infected by COVID-19 positive hairdressers who did not wear masks.

Similarly, CDC director Dr. Rochelle Walensky has repeatedly cited an observational Arizona study claiming that school districts without mask mandates were 3.5 times more likely to have COVID outbreaks than districts that required masks. The study is an outlier in the literature and, as David Zweig showed in The Atlantic, has multiple methodological problems rendering its conclusions worthless.

The CDC’s about-face on masks for general use appeared to be a demonstration it is doing something. Following the recent court decision striking down the federal transportation mask mandate, the agency still insists masks are needed.

But the CDC’s failure to seek a stay pending appeal suggests the agency doesn’t really believe masks are beneficial. Generalized mask mandates had little benefit.