Weak Evidence For Masks

One reason that we were originally advised to not wear a face mask is because every randomized controlled trial over the past 10 years has shown that they are not effective at preventing the transmission of respiratory viruses by droplets and aerosols.

For example, the most recent review published in May 2020 concluded as follows:

“Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza.”1

The science has not changed- 10 years of consistent high quality studies with low risk of bias have provided substantial evidence against the effectiveness of face masks for the general public in non health-care settings.

One recent study that concluded mask use was the best solution to stopping the spread of Covid-19 was so gravely flawed that a group of researchers from Stanford and John Hopkins universities submitted a formal request to have the study immediately retracted, expressing their deep concerns that “the claims presented in this study are dangerously misleading and lack any basis in evidence”.2

Science is the most important tool we have for battling epidemics and, as I wrote about back in February, the danger of scientists in the media carelessly misinterpreting evidence, or failing to communicate clearly, is that the public will lose their trust in science when it matters most.

Science does not flip flop overnight, that’s what distinguishes it from politics.

If politicians want to encourage more people to wear face masks they should consider having clear, evidence-based communication strategies, and not pass laws that force people to implement measures that, at best, are only supported by weak scientific evidence.

I would like to take this opportunity to thank all the scientists worldwide who are standing up to protect the sanctity of their field, I can only imagine how frustrating this has been for them.

Marc Jaoudé
Markito Fitness & Nutrition



  1. Xiao, Jingyi & Shiu, Eunice & Gao, Huizhi & Wong, Jessica & Fong, Min Whui & Ryu, Sukhyun & Cowling, Benjamin. (2020). Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings-Personal Protective and Environmental Measures. Emerging infectious diseases. 26. 967-975. 10.3201/eid2605.190994. – https://cdc.gov/eid/article/26/5/19-0994_article.
  2. Formal request for the retraction of Zhang et al., 2020. (n.d.). Retrieved July 09, 2020, from https://metrics.stanford.edu/PNAS%20retraction%20request%20LoE%20061820

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