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MIT Sloan study: Summer’s heat and humidity not going to stop the coronavirus

Warm weather and humidity won't stop the coronavirus, a new study from the MIT Sloan School suggests. Above, a scene along the Charles during recent good weather.Pat Greenhouse/Globe Staff

Don’t expect the coronavirus to disappear with the arrival of hot and humid weather this summer.

That’s the message from new research led by the MIT Sloan School of Management that looked at how the coronavirus pandemic has been affected by weather since it first erupted.

“Even though high temperatures and humidity can moderately reduce the transmission rates of coronavirus, the pandemic is not likely to diminish solely due to summer weather,” said Hazhir Rahmandad, an associate professor of system dynamics, in a statement from the Sloan School.

The research adds to a growing body of evidence that COVID-19 is unlike the seasonal flu, which does dissipate as the weather warms. Most studies have found weak evidence that high temperatures and humidity will vanquish the virus, the Globe reported last month.


The team that worked on the latest study included researchers from Harvard, Massachusetts General Hospital, the University of Connecticut, and Virginia Tech.

In the study, the researchers assembled one of the most comprehensive data sets of the global spread of the pandemic to date, the statement said.

They looked at virus transmission and weather statistics across more than 3,700 locations across the world from Dec. 12 to April 22.

They estimated how different weather variables were associated with the pandemic and then used those estimates to project the impact of the weather on virus transmission in coming months. The researchers posted their work on a website.

“The results provide evidence for the relationship between several weather variables and the spread of COVID-19, finding a negative association between temperature and humidity and transmission. … Summer may offer partial relief to some regions of the world. However, the estimated impact of summer weather on transmission risk is not large enough in most places to quench the epidemic, indicating that policymakers and the public should remain vigilant in their responses to the pandemic, rather than assuming that summer climate naturally prevents transmission,” said a working paper posted by the researchers.


The study’s results underscore the need to continue social distancing, quarantining, hand washing, and other measures, Rahmandad said in the statement. “At best, weather plays only a secondary role in the control of the pandemic," he said.

David R. Walt, a pathology professor at Harvard Medical School and Brigham and Women’s Hospital who was coauthor of a recent report from the National Academies of Sciences, Engineering and Medicine that downplayed the impact of warm weather on the coronavirus, said he agreed with the MIT research’s conclusion.

The National Academies report “came to a similar conclusion ... These new data further corroborate this conclusion," Walt said in an e-mail.

Michael Mina, assistant professor of epidemiology at Harvard T.H. Chan School of Public Health, said Friday in a media briefing that summer weather “might slow [the coronavirus] down a little bit, but I don’t anticipate that it will actually stop it.”

He cautioned that there is still a “massive number” of people in the population who could be susceptible to the virus and warned that if social distancing measures are relaxed over the summer, “I do think that we will see pretty consistent spread" and possibly a worst-case scenario of “big outbreaks” in the fall.

Martin finucane can be reached at martin.finucane@globe.com.