Guest column: COVID, vaccine, and mask disinformation. Again.
The guest essay “Covid lab leak wasn’t just a’ fringe’ theory” by Ingrid Jacques of USA TODAY in the Press-Citizen on March 4 casts doubt on the effectiveness of using masks to prevent the spread of Covid-19. She quotes a flawed and frequently misinterpreted review of multiple studies in the Jan 23, 2023, Cochrane Library, Physical interventions to interrupt or reduce the spread of respiratory viruses. This meta-analysis stated that wearing a face mask made “little or no difference” in the number of influenza and COVID-19 cases.
This false narrative based on misinterpretations of the Cochrane Library review, that masks don’t prevent COVID infections, was shared widely on social media as evidence that masks don’t work.
Fox News and other outlets claimed that the CDC had “exaggerated” the evidence supporting mask mandates.
However, this interpretation of the Cochrane review is misleading and unsupported by the review’s analysis because of its faulty methodology and false assumptions about transmission.
These flaws and misleading conclusions in the Cochrane Library meta-analysis are described in an article in The Conversation, “Yes, Masks Reduce the Risk of Spreading COVID, Despite a Review Saying They Don’t”. It was written by epidemiologists Raina MacIntyre, Abrar Ahmad Chughtai, David Fisman, and primary health care professor Trish Greenhalgh.
Here are some of the limitations and flaws of the Cochrane Library review described in an article from Health Feedback, “Multiple studies show that face masks reduce the spread of COVID-19; a Cochrane review doesn’t demonstrate otherwise”:
The review only addressed part of the benefits of mask-wearing. The authors noted “Face masks and respirators work in two ways: they protect the wearer from becoming infected and they prevent an infected wearer from spreading their germs to other people. Most of the randomized control trials (RCTs) in the Cochrane Review looked only at the former scenario, not the latter.”
There were multiple methodological limitations in the Cochrane Library review which reduced the reliability of the results. The authors of the review explained in the Discussion that the available RCTs evaluating mask effectiveness were of “variable quality”.
Another important limitation of the review is that the RCTs included in the analysis evaluated the effect of face masks on several respiratory viruses in different populations and multiple settings with variable risks of transmission.
Most of the participants in the individual RCTs didn’t wear face masks consistently during the trial.
In addition, the Cochrane Library review mentioned other factors that might have influenced the results, including the quality and material of the mask, contamination by hands of saliva, and possible changes towards riskier behavior in people who wore masks due to an exaggerated sense of security.”
The authors of The Conversation article conclude:
“Yes, masks reduce the spread of COVID.
"There is strong and consistent evidence for the effectiveness of masks and (even more so) respirators in protecting against respiratory infections. Masks are an important protection against serious infections.
"Current COVID vaccines protect against death and hospitalization, but do not prevent infection well due to waning vaccine immunity and substantial immune escape from new variants.
"A systematic review is only as good as the rigor it employs in combining similar studies of similar interventions, with similar measurement of outcomes. When very different studies of different interventions are combined, the results are not informative.”
We all need to be willing to separate truth from fiction, fact from fallacy as best we can in this current Age of Rampant Disinformation.
John Macatee is a retired physician and a member of the Iowa City Press-Citizen editorial board. Contact: jrmacatee@gmail.com.
This article originally appeared on Iowa City Press-Citizen: Opinion: COVID, vaccine, and mask disinformation. Again.
