scorecardresearch Skip to main content

Harvard epidemiologist warns of possible tough coronavirus winter ahead

A coronavirus testing site in Winthrop this week.Erin Clark/Globe Staff

A Harvard epidemiologist is warning that if the United States doesn’t get the coronavirus under control now, it is headed for a “perfect and terrible storm.”

Dr. Michael Mina, an epidemiology professor and a core member of the Center for Communicable Disease Dynamics at the Harvard T.H. Chan School of Public Health,said “massive increases” in infections are possible.

“Winter is coming,” Mina said in a series of tweets. “If we do not get this virus under control now, we are in for a perfect and terrible storm.”

“We are not taking the expected seasonality of this SEASONAL virus seriously!” he continued. The tweets included a chart from a study that suggested coronaviruses tend to thrive in the winter months.


Mina said he worried that people had drawn an incorrect lesson from the fact that SARS-CoV-2 — the novel coronavirus that causes COVID-19 — continued to rage through the summer: that the virus is not the kind that will strengthen in coming months.

To think that, he said, would be a “grave mistake and misinterpretation.”

“Mistaking ongoing transmission in the summer for a ‘less seasonal virus’ is not smart. All evidence points in the other direction,” Mina wrote.

“We could have been much more ready now,” he said. “But instead we are just giving the virus a major headstart at the very time when it has its guard down.”

Dr. Amesh Adalja, an infectious disease specialist who is a senior scholar at the Johns Hopkins Center for Health Security, said he agreed with Mina.

“We have to prepare … for transmission to accelerate,” he said in a telephone interview. “That’s what happens every year with the four other coronaviruses.”

He said steps should be taken now to ensure adequate hospital capacity, personal protective equipment, diagnostic testing, and contact tracing in the months ahead.


The outlook in Massachusetts is more promising, another public health official said.

Dr. Ashish Jha, who until last month headed the Harvard Global Health Institute, said Wednesday that he is concerned the state is “going in the wrong direction,” but he doesn’t expect to see numbers in the fall and winter like those of the spring.

“We would really have to screw things up very, very badly, and that’s not going to happen. The governor’s not going to let that happen,” said Jha, who is now the dean of the Brown University School of Public Health.

Jha cautioned, though, that the increasing prevalence of the virus makes it difficult to safely reopen schools and other public facilities. He said the coming months will likely bring many smaller, targeted local closures but nothing like the statewide shutdown of the spring.

“I think that the lesson from March and April is that the earlier you act, the less draconian you have to be and the more lives you can save. … I have never seen any locality, any area, that’s been upset because they acted too quickly,” he said.

On Wednesday, the Massachusetts Department of Public Health reported 21 new hospitalizations and 509 new cases, marking the 15th consecutive day reported cases in the state have exceeded 300.

Case tallies and positive test rate metrics have in the past two weeks reached their highest levels since at least June, when the state was still on the descent from April’s harrowing peaks.


On Tuesday, Governor Charlie Baker attributed the upward trends to increased testing and the onset of autumn.

“We expected and anticipated that there would be an increase in the fall,” he said.

In a media briefing Wednesday, Dr. Roger Shapiro, an associate professor of immunology and infectious diseases at Harvard’s Chan School, noted a worrisome trend in recent national data.

“A lot of people talk about the COVID outbreak as a wave that’s going across the country. And you’ve probably heard many people say, well, we’re still in the first wave. I think a better way of thinking about it is a wave that went into a pool," Shapiro said.

“And in that pool, it’s sloshing around. And ... wherever it hasn’t been yet, it’s going to go, because it’s just like sloshing around in a wading pool. And that’s what the country essentially is doing," he said.

"So the places where it hasn’t been, it will go. To places where it has already been, it can go back. Because we don’t have anything close to the herd immunity” needed for the pandemic to subside, he added.

Correspondent Jeremy C. Fox contributed to this story.

Read Mina’s full thread:

Martin Finucane can be reached at