Klaus Vedfelt/DigitalVision/Getty Images

What could a second wave of coronavirus look like in the U.S.?

The brisk days of autumn are upon us, which means, so, too is the dreaded “second wave” of coronavirus infections, or the at the very least, we’re nearing it. The name alone sounds nothing short of ominous, but what, exactly, would a second wave of coronavirus look like in the U.S.? Mic posed the question to health experts.

All forecast a spike in COVID-19 cases, especially among young people — although they can still infect older people, suffer long-term effects, and even get seriously ill or die from it — but the specifics will vary by region. They also worry about this spike coinciding with the flu season, which could overburden the healthcare system. The good news: We’re not doomed. We can dampen or even prevent the next wave, if we take adequate precautions.

“We’re going to probably see a little bit of an uptick [in COVID-19 cases] in October, taking off in November and December,” says Henry Raymond, an epidemiologist and associate director for public health at Rutgers University Center for COVID-19 Response and Pandemic Preparedness.

The distinctness of that uptick, though, will likely depend on where you live. In the Northeast, where “we definitely have been through the first wave,” people will experience a distinct second wave. And in the Midwest and the South, which still appear to be in the midst of the first wave, the two waves will likely blur together. The second wave “is going to be more subtle where people are engaging in mitigation efforts and less subtle where they’re not,” says Raymond, with the caveat that he’s only speculating at this point. Because of its size and diversity, California is “more of a mixed bag,” almost a microcosm of the entire country, where we can expect to see a discernable second wave in some places, and a blurring of the first and second waves in others.

Larry Chang, an infectious disease expert and associate professor of medicine at Johns Hopkins Medicine, believes the U.S. may already be entering a third wave. The first wave included the surge in cases in the Northeast earlier this year, and the second included the hotspots that later emerged in California and the South. “We’ve initially started coming down from that, and in the past week or so, we’ve seen a rise,” Chang tells Mic.

Whatever wave we’re in, the point is, we’ve never sufficiently brought down the number of active infections before they rose again, a trajectory Chang likens to descending from a mountaintop but landing nowhere near the ground.

“That’s set us up for future waves that might be even bigger than the first wave,” he says.

Although she believes we still have yet to emerge from the first wave, Sadiya Khan, an assistant professor of preventive medicine and an epidemiologist at Northwestern University Feinberg School of Medicine, has a similar assessment. “It’s not so much we’re anticipating a second wave, but worsening within the first wave without ever reaching control.”

Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, would probably agree. On The Daily Show with Trevor Noah on Monday night, he said we’d brought down the number of new cases a day from 70,000 during initial efforts to re-open the economy to 30,000 to 40,000 — but worries this number is still higher than it should be as we head into fall.

The risk of another wave in a given location, then, depends on how well it’s controlled the virus. New York City, which did a great job driving down the amount of virus circulating through the community, probably has the least risk of a second wave, Chang notes. On the other hand, places that haven’t controlled the virus as effectively, like Florida, or those currently seeing a rise in cases, like Missouri, still have a good-sized pool of virus circulating through the community. “That’s fuel for the fire to have another wave.”

But the country as a whole, even places with low rates of infection at the moment, is at heightened risk for another wave as temperatures dip, Chang says. “I think we’re seeing all these things that could create the perfect storm for another big wave.”

For starters, the cold tends to drive people indoors, which often means less physical distancing, making it easier for the novel coronavirus to spread. Although it doesn’t render you immune, “being outdoors is incredibly protective against the virus,” Chang explains.

Studies have also shown that certain bodily defenses against viral infection, like mucus and cilia, might not work as efficiently in cold, dry environments, he adds. While we haven’t yet studied whether these conditions might also make us more vulnerable to infection with the novel coronavirus, “there are similar concerns given the behavior of similar viruses.”

The virus may also be slightly more stable in the cold, which might make it more transmissible, Chang adds, although we can’t say for sure yet. But Khan thinks that the increased risk of infection in chillier months probably has more to do with people’s behavior — like increased socializing indoors — than something about the virus.

Another possible contributor to the next coronavirus wave? The flu and other respiratory diseases, which are more common in the fall and winter and could make you more susceptible to COVID-19. “If your immune system is already struggling with the common flu or common cold, and you come across this new virus, theoretically, your body’s not going to be prepared to deal with that all at once,” Raymond explains. Indeed, Khan notes that places that see more flu cases will likely see more COVID-19 cases, too.

An overlap of the pandemic and flu season — which typically starts in October and ends in May at the latest in the U.S. — could also overburden hospitals. “When they’re overburdened, it can lead to more deaths,” Chang says. While COVID-19 hospitalizations aren’t surging like they were earlier this year, they still place a constant baseline burden on hospitals, and flu is tough enough as it is on the hospital system, Khan says. How tough? According to CDC estimates, there were 490,600 hospitalizations during the 2018 to 2019 flu season.

But efforts to minimize COVID-19 transmission could also lower the risk of the flu, Chang says. Indeed, the WHO found that Australia and other Southern Hemisphere countries had the lowest number of flu cases on record this season, or April to September. “If we are all more vigorous with mask wearing and hand washing, and our flu vaccination rate doubles from 40% to 80%, I think there’s hope,” Khan says. We can avoid a “twin-demic,” in other words.

Raymond predicts that the next wave might entail an uptick in positive test rates, but not necessarily hospitalization and death rates. “I think medical folks have gotten much smarter about how to treat this,” he explains. “I think that it’s also shifting to different populations. We may have a lot more cases theoretically, but I think it’s going to be in younger people.” Chang and Khan agree that the next wave will likely skew younger, especially with the re-opening of K-12 schools and college campuses. That said, COVID-19 can still have terrible effects in young people that linger for weeks or months, as Fauci noted, per CNN, including cardiovascular abnormalities and others that only time and research will fully unravel. And as Chang points out, young people aren’t completely immune from getting severely ill or dying of COVID-19, even if their risk is lower.

They could also still come into contact with older people, Raymond notes. Infections that start in younger groups tend to spread to older age groups over time, Chang explains, since it’s so hard to completely isolate one age group from another. Asymptomatic college students could conceivably come home on Thanksgiving and unwittingly infect their parents or grandparents.

But “none of this is inevitable,” Chang says. “The next wave could be blunted or prevented if people up their use of these interventions which we know to work.” As exhausting as it is, continue measures like wearing a mask and maintaining physical distance from people outside your immediate bubble, Khan urges. Chang suggests planning ahead about how to bring activities you normally do indoors outside even when it’s cold, like investing in fire pits or heating lamps, if you can.

All three experts Mic interviewed strongly recommended getting a flu shot, which Khan referred to as “the most important thing we can do right now.” Even though they’re not 100% effective, she says, they’ll ensure you’ll get a milder flu if you do get sick.

Raymond is most concerned about places in the U.S. that were late in adopting in mitigation protocols or are resistant in doing so. While it’s within our power, and those of our leaders, to keep the next wave at bay, we need to act with swiftness and vigilance. “I really just think that people are a little too hopeful that this is just going to go away,” Raymond says.