This winter, moving outdoor gatherings indoors could contribute to further increases in COVID-19 cases and deaths. “The winter could get a lot worse than even now,” Noymer said. “There’s plenty of room [in the population] for this thing to expand.”
“We know that the biggest risk of spread for this virus is when meaningful numbers of people gather indoors for any extended period of time,” Jha said. “Also, people are already feeling pandemic fatigue, and I think that'll only get worse.” Due to the combination of indoor transmission risk and that increased desire to gather, he thinks “there almost surely will be a spike in cases” this winter.
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Though data on the coronavirus’s circulation during winter are scant, other respiratory viruses, such as influenza, tend to spread more readily in the winter than the summer. Noymer mentioned some possible explanations for this—that people spend more time indoors together, that the lower level of humidity suits the viruses better, that our mucous membranes get drier and more vulnerable to infection—and said he would be surprised if the coronavirus weren’t aided in colder months by these or other forces.
Making matters worse, the pandemic will, if it isn’t somehow neutralized, coincide with flu season, which usually starts in October and is at its worst December through February. Even though researchers don’t yet know how severe this year’s flu season will be, this overlap is worrying for three main reasons.
First, even in the absence of a pandemic, flu season can tax hospitals’ beds and resources, Noymer said; having both the flu and COVID-19 spreading at once could further strain an already strained health-care system. Second, “COVID compromises the respiratory system and so does flu, so each of them makes the other one worse,” Vlahov told me. (He says that everyone who’s able should get the flu vaccine this year.) And third, because the two diseases have some symptoms in common, telling them apart can be difficult. That in turn can hinder efforts in hospitals to identify suspected COVID-19 cases, Vlahov said. It also could prompt worry and fear in people who don’t know which disease they’ve come down with, notes Steven Taylor, the author of The Psychology of Pandemics.
Winter will be different from now in important, distressing ways, but in other ways it will be familiar. Looking ahead to the colder months, Vlahov thinks that they could resemble the homebound early stages of the pandemic, when many people who were able to “just stayed home and once a week went out for 20 minutes to get some grocery shopping done.”
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And many Americans are currently living in places where being outdoors for long periods of time already isn't feasible, because of the summer heat. A seasonal shift toward cooler indoor gatherings, Jha thought, might have contributed to rising case counts in some states that have had large outbreaks recently, such as Arizona and Texas. “It’s not [primarily] about summer or winter,” he explained. “It’s about outdoors versus indoors … Arizona in June is like Boston in December.”