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A Stanford University study concluded that face masks worn to prevent the transmission of COVID-19 do not work.

The study has been rejected by Stanford. The University has clarified that the author Baruch Vainshelboim is not affiliated with them.

A claim has been making rounds on social media questioning the efficacy of the face masks against Covid-19. The social media posts are based on a 'study,' claiming to be published by the Stanford University. This is misleading information. The study claims that "facemasks are ineffective" in "blocking viral particles due to their differences in scales." It goes on to say that this is due to the virus being able to pass through the threads in masks: "the virus SARS-CoV-2 has a diameter of 60 nm to 140 nm [nanometers (billionth of a meter)], while medical and non-medical facemasks' thread diameter ranges from 55 µm to 440 µm [micrometers (one-millionth of a meter), which is more than 1000 times larger. Due to the difference in sizes between SARS-CoV-2 diameter and facemasks thread diameter (the virus is 1000 times smaller), SARS-CoV-2 can easily pass through any facemask". The study further suggests that "among symptomatic individuals, there was no difference between wearing and not wearing facemask for coronavirus droplets". In the study, the author, Baruch Vainshelboim's credentials are cited as "Cardiology Division, Veterans Affairs Palo Alto Health Care System/Stanford University, Palo Alto, CA, United States." On April 2022, Stanford Medicine's official Twitter account clarified that the research was "not a Stanford study," In fact, the author's affiliation was "wrongly attributed to Stanford." It further said that the University had requested a correction. It noted that author, Baruch Vainshelboim, had no affiliation with VA Palo Alto Health System or Stanford at the time of publication". It further added that the author has not had any affiliation with the University since 2016. It said, before 2016, he was a visiting scholar at the University "on matters unrelated to this paper." Stanford University has encouraged people to continue to wear masks to protect them from COVID-19. The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.

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