Fact check: Studies do show face masks and lockdowns slow the spread of COVID-19

Social media users have been sharing posts online that claim there is no evidence that face masks or lockdowns slow the spread of COVID-19. This claim is false.

Reuters Fact Check. REUTERS

Examples can be seen  here  ,  here  and  here  .

The posts show a tweet from politician Kimberly Klacik that reads: “Not sure who needs to hear this… The fact that it’s been a year & there is still no evidence masks or lockdowns slow the spread of #COVID19, this has been a year long conspiracy theory that has devastated families from coast to coast.”

The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend the use of face masks to reduce the spread of COVID-19 along with other measures of prevention such as social distancing, frequently washing hands, and avoiding crowds and poorly ventilated spaces. (here and here)


There are several studies conducted in different locations that show wearing a face mask helps reduce the spread of disease.

The CDC in January 2021 conducted experiments to see how well wearing a cloth mask over a three-ply medical procedure mask and knotting the ear loops of a surgical mask and then tucking the excess material close to the face, protects against COVID-19 (here).

They found that both these methods helped reduce the exposure to potentially infected aerosols by more than 90% in laboratory simulations. The data also showed that wearing a mask helped reduce exposure to aerosol particles that were the size of droplets that spread COVID-19, when compared to wearing no mask at all (here). More information about the study can be found here .

A study in Kansas here comparing counties with mask mandates with counties without between June 1 and Aug. 23, 2020 found that the rates of COVID-19 declined in counties with mask mandates. 

A study the Proceedings of the National Academy of Sciences of the USA (PNAS) found that infection trends shifted dramatically when mask-wearing rules were implemented on April 6 in northern Italy and April 17 in New York City - at the time among the hardest hit areas of the world by the health crisis. (here ).


Reuters Fact Check has previously debunked the claim that lockdowns do not work to slow the spread of COVID-19  here  .

Reuters contacted two experts, Dr. Elizabeth Stuart, Associate Dean for Education at the Johns Hopkins Bloomberg School of Public Health ( here  ) and Dr. Stuart Ray, infectious disease expert with the Johns Hopkins University School of Medicine ( here  ) .

Both confirmed that lockdowns do reduce transmission of the SARS-Cov-2 and highlighted that a more “targeted” or “proportional” approach of restrictions can mitigate the risk of infection, while balancing other concerns about the economy and mental health.

Ray pointed to evidence ( here  and here  ) that has suggested that the spread of SARS-CoV-2, the virus that causes COVID-19, is mitigated by “progressively stringent measures,” such as stay-at-home orders.

More than 28 million COVID-19 cases have rocked the United States and 513,721 people have died, even as daily average deaths and hospitalizations have fallen to the lowest levels since before the Thanksgiving and Christmas holidays. The virus took a full year off the average life expectancy in the United States, the biggest decline since World War Two (here ).


False. Lockdowns and face masks have been proven to slow the spread of COVID-19. The CDC and the WHO recommend the use of face masks, social distancing, frequently washing hands and other measures to reduce the spread.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work  here  .