Top Medical Institute Finds Little Evidence for N95 Masks

The Cochrane Library, a top institute of medical research affiliated with the World Health Organization, has found no clear benefit to the use of N95 masks for preventing Covid-19. Based on dozens of studies from a diverse set of countries and situations, Cochrane researchers concluded that “There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infections.” They added that “Harms associated with physical interventions [including the N95s] were under-investigated.” [1]

Despite being endorsed by WHO and CDC in June 2020, surgical masks have never been shown by real-life, in-field trials to prevent Covid transmission. The research literature in 2020 was better represented by Anthony Fauci’s original claim in February of that year that masks were pointless in preventing community spread of viruses. Although Fauci has stated that he misled the public in order to preserve mask supplies for healthcare workers, his declassified emails seem to show he himself believed the anti-mask medical literature. [2]

Since then, one open access journal meta-analysis has stated that N95s are more effective than surgical masks; the analyis is only based on four studies, however, one of which the authors admitted is highly biased. Cochrane’s meta-analysis was based on 67 studies.

In spite of there being no compelling evidence they prevent Covid, officials in California have mandated N95-style masks for schoolchildren. There are no peer-reviewed studies on the use of N95s on children, and in fact, no such thing as an “N95 made for kids.” KN95 masks (the kind now marketed to children) have never been approved by the National Institute for Occupational Safety and Health, the organization which validates N95s. The World Health Organization actually advises against masking children under six. [3]

In The British Medical Journal, three top medical professors, Monica Gandhi and Vinay Prasad of the University of California, and Stefan Baral of Johns Hopkins, lamented such mandates last year: “In the beginning precaution is fine, but eventually public health must be driven by data.” The three doctors went on to criticize legitimate scientific debate being dragged down to partisan bickering. “Various non-pharmacologic interventions for covid-19,” they wrote, “are increasingly seen as markers of being on the political left or right.”  [4]

In more recent public comments, Dr. Prasad, professor of epidemiology at UC-San Francisco, continued to denounce the misleading politicization of what ought to be straightforward physical analysis: “At this point, I have to conclude most people are political ideologues on this issue. I am a progressive-liberal, but I interpret data for a living, and I am confident the evidence is weak…It looks like Cochrane [International Medical Library] also agrees with me that we needed cluster randomized control trials” on N95s before there can be any kind of mandate. The professor concluded: “We are recommending something that is incredibly polarizing with no clear evidence.”  [5]


  1. “Do physical measures such as wearing masks stop or slow down the spread of respiratory viruses?” by Tom Jefferson, Chris Del Mar, et al,
  2. Newsweek, “Fauci Said Masks ‘Not Really Effective in Keeping Out Virus,’ Email Reveals” June 2, 2021
  3. Vinay Prasad MD, “The Cult of Masked Schoolchildren,” Tablet magazine, Jan 19, 2022
  4. “What Does Public Health Really Mean? Lessons from Covid-19,” The BMJ, July 26, 2021
  5. Vinay Prasad, MD, MPH, at, March 22, 2022

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