Do face-masks help people to fight Coronavirus? Many scientists will say it does. But some people including US President Donald Trump and White House task force member Scott Atlas would disagree. Here is a new study, published on Wednesday, that reiterates Trump's belief as it found people contracted Covid-19 despite wearing masks.
Based on a randomized controlled trial, Denmark scientists found that surgical masks do not protect the Wearers against Coronavirus infection. The study which was published in the Annals of Internal Medicine did not contradict evidence that masks can prevent virus transmission from the wearer to others, but it faced massive criticism from other experts.
The study stated that the recommendation to wear surgical masks to supplement other public health measures did not reduce the Coronavirus infection rate among wearers "by more than 50 percent in a community with modest infection rates, some degree of social distancing, and uncommon general mask use."
There Are Limitations
A group of cardiologists in Denmark conducted the study on 6,000 participants, half of whom were told to wear masks and half of whom were not. Researchers at the University of Copenhagen found that 42 of the participants who were asked to wear masks contracted the Coronavirus caused disease, while 53 of the participants in the control group got COVID-19—a difference which the study authors said was not statistically significant. However, the study did not investigate whether masks prevented people infected by the virus from infecting others.
Some experts swiftly pointed out that the study has several limitations, such as low compliance—many participants did not complete the study and a high number of people who were supposed to wear mask did not use it—and the research was conducted in a population where the spread of SARS-CoV-2 virus was already low.
However, there are many studies that clearly suggest that mask-wearing has helped people to lower the transmission rate. In October, a study by Vanderbilt University researchers showed that mask-wearing has a big impact on Covid-19. The analysis revealed that in Tennessee mask mandates had lower hospitalization rates.
The Critics
Dr. Tom Frieden, former Director for the US Centers for Disease Control and Prevention (CDC), wrote a response to the study while stating that among the limitations, the researchers behind the new study used antibody tests to diagnose Coronavirus cases that could have led to a significant number of false positives. He also added that the authors did not make an effort to make sure that participants who were told to wear masks wore them correctly, or at all times.
"There is absolutely no doubt that masks work as source control," said Dr. Frieden adding that "the question this study was designed to answer is: Do they work as personal protection"? According to him, the answer depends on what mask is used and what sort of exposure to the Coronavirus each person has. He also clarified a few facts that "an N95 mask is better than a surgical mask. A surgical mask is better than most cloth masks. A cloth mask is better than nothing".
Dr. Elizabeth Halloran, a statistician at Fred Hutchinson Cancer Research Center in Seattle told the New York Times, "if you show this article to a health care provider who works in a COVID-19 ward in a hospital, I doubt she or he would say that this article convinces them not to wear a mask."
Dr. Henning Bundgaard, professor of Cardiology at Rigshospitalet in Denmark and lead author of the Danish study said, "Our study gives an indication of how much you gain from wearing a mask." Even though it showed not a lot, "a small degree of protection is worth using the face masks, because you are protecting yourself against a potentially life-threatening disease".
However, Dr. Christine Laine, editor-in-chief of Annals of Internal Medicine and an internal medicine physician said the study did not answer the question about whether widespread masking mitigates Coronavirus infection. She also said that the study was allowed to get published as it is the only randomized control trial of masks for COVID-19 that has been done to date and added that "this was an important, well-designed study".
