A recent Cochrane review of mask use found that masks are not effective in reducing the spread of respiratory viruses.
Cochrane reviews assess the highest-quality studies of medical literature on specific topics. The researchers who conducted the review, which assessed the effectiveness of masks and hand hygiene, said masks probably make “little to no difference in how many people have confirmed flu.” However, hand hygiene programs “may reduce the number of people who catch a respiratory or flu-like illness.”
The researchers looked through large medical databases such as CENTRAL, PubMed, and Embase for well-controlled studies in which one intervention is compared to another, known as randomized controlled trials (RCTs) and cluster RCTs, in which groups or clusters of individuals are randomized rather than individuals themselves.
The study, published on Jan. 30, examined 78 RCTs and cluster RCTs published through October 2022. Six of the new studies were conducted during the COVID-19 pandemic.
Physical measures such as screening at entry ports, quarantine, and social distancing to stop or slow the infection of acute respiratory viruses (ARVs) such as those causing influenza, SARS (severe acute respiratory syndrome), and COVID-19 were also included in the review, but the authors were unable to find any high-quality studies to assess these interventions.
The review is an update to a previous one published in November 2020.
Medical or Surgical Masks
Of the studies reviewed by the authors regarding masks, 10 took place in communities and two studies were among health care workers.
“Compared with wearing no mask in the community studies only, wearing a mask may make little to no difference in how many people caught a flu-like illness/COVID-like illness,” the authors concluded.
In addition, it “probably makes little or no difference in how many people have flu/COVID confirmed by a laboratory test.”
Reports of unwanted effects resulting from mask use were rare and of poorly quality.
Similar results were found in an RCT study from Guinea-Bissau published on Jan. 5 in The Lancet.
The study, not yet peer-reviewed, was conducted between July 20, 2020, and Jan. 22, 2021, and included more than 39,000 participants.
“New Cochrane meta-analysis of RCTs shows masks don’t work. New COVID mask RCT from Guinea Bissau shows masks don’t work. Throw that onto the pile of old COVID/flu mask RCTs that show masks don’t work. It’s done. Move on,” said Margery Smelkinson, an infectious diseases scientist at the U.S. National Institute of Allergy and Infectious Diseases, on Twitter.
She said in a Jan. 14 video attached to the post, “Why are we focusing on these lower quality observational studies when we have these better, randomized controlled trials?”
There have been many RCTs on flu in health care workers, and they’ve found that masks have no effect. So three years into the COVID-19 pandemic, Smelkinson asked, why do we continue to promote masking?
When comparing N95 respirators to medical or surgical masks, the authors noted that they were “uncertain whether wearing masks or N95/P2 respirators helps to slow the spread of respiratory viruses,” based on the studies they assessed.
“N95” refers to the U.S. testing requirements, and the P2 classification is in accordance with European testing requirements.
The researchers reviewed four studies that were conducted on health care workers and one small study in the community.
Wearing N95/P2 respirators probably made “little to no difference” in how many people were confirmed with flu, a flu-like illness, or a respiratory illness.
Harms from wearing the masks were not well-reported in this case either.
Evidence was limited by imprecision and heterogeneity for these subjective outcomes.
The authors noted medical or surgical masks “were non-inferior” to N95 respirators, according to a recent study of 1,009 health care workers in four countries providing direct care to COVID-19 patients.
“There is no proof for the effectiveness of wearing masks to prevent infection with a respiratory virus in the community,” Yoav Yehezkelli, a medical doctor and former lecturer in the Department of Emergency and Disaster Management at Tel Aviv University in Israel, told The Epoch Times.
The review strongly supports the conclusion that he and his colleagues came to at the start of the COVID-19 pandemic, he said. Yehezkelli was one of the founders of the Epidemic Management Team and Evaluation Programs for Extreme Biological Incidents—a professional body that advises the director general of the Israel Ministry of Health (MOH).
In December, he co-authored a letter titled “Masks for Prevention of Respiratory Infections—Is It Evidence-Based Medicine?” that was sent to the Israel Medical Association Journal, and which said that mask mandates—which still remain in effect in medical facilities in Israel—are not evidence-based.
The U.S. Centers for Disease Control and Prevention continues to recommend masks in communities where the prevalence of COVID-19 remains high.
According to Yehezkelli, there are studies that showed that masks had some effect, and some studies showed that there is no effect, but there is no proof that masks are effective.
The findings regarding N95 were a bit surprising, Yehezkelli said, “since in terms of biological logic, the N95 mask is supposed to have a better protective effect.”
Yehezkelli emphasized that in his professional opinion, during an encounter between a doctor and a patient who is suspected of having or who has COVID-19 or another respiratory disease, “there is value in masks and even more so in the N95 mask, but the studies simply did not examine this specific situation.”
Another noteworthy finding in the review, according to Yehezkelli, is that hand-washing does reduce infection from respiratory diseases, to a moderate extent.
The review found that interventions such as hand-washing and using hand sanitizer “may reduce the number of people who catch a respiratory or flu‐like illness, or have confirmed flu.”
“Comparing hand hygiene interventions with controls (i.e. no intervention), there was a 14% relative reduction in the number of people with ARIs in the hand hygiene group,” it states.
This probable benefit would result in a reduction from 380 events per 1,000 people to 327 per 1,000 people in absolute terms, the authors said.
Yet this effect was not statistically significant with more strictly defined outcomes of influenza-like illness and laboratory-confirmed influenza, suggesting that the intervention “made little or no difference.”
There were only a few studies that examined unwanted effects. They mentioned skin irritation as a result of using hand sanitizer.
High Risk for Bias
The researchers note that it was hard to draw clear conclusions due to high risk for bias in the assessed studies, variation in measurements of the outcome, and low adherence with the interventions during the trials.
The studies were done in different countries and in different settings, during nonepidemic influenza periods, epidemic influenza seasons up to 2016, the global H1N1 influenza pandemic in 2009, and the COVID-19 pandemic.
In addition, there were a few additional RCTs during the pandemic related to physical interventions, but none of them dealt with the issue of mask quality and adherence to wearing masks properly, which are both important for evaluating effectiveness.
The authors noted that their confidence in the results was “low to moderate” regarding the subjective outcomes related to respiratory illness, and confidence in the results was moderate for the more accurately defined laboratory-confirmed respiratory virus infection, related to masks and N95/P2 respirators.
This highlights the fact that in public health policy, one cannot enforce on the population measures that are not scientifically proven, Yehezkelli said.
“It is actually very unfortunate that the public—not only in Israel but also in the world—was forced for a very long time to wear masks,” he said.
“It is a bit sad that especially professional bodies such as medical bodies supported such a policy … even though it was clear from the beginning that it is not useful.”