Share on Pinterest
Experts hope vaccinations as well as safety protocols will help minimize any increase this winter in COVID-19 cases.
Anastasiia Shavshyna/Getty Images
  • New COVID-19 cases have started to rise in some Northern states, causing experts to express concern that colder winter weather could drive cases back up.
  • They say that’s because people tend to congregate more indoors when it’s colder. In addition, people will travel during the holidays.
  • However, they note that the higher number of vaccinated people as well as infection-acquired immunity and continued safety protocols could keep the increase to a minimum.

If you’ve been following the data on COVID-19, you’d see why there has been reason for some optimism.

The number of new cases, hospitalizations, and deaths have decreased in recent weeks as more people get vaccinated, and safety protocols remain intact in many places.

But over the past few weeks, the number of cases is edging back up in some Northeastern and Midwestern states, as they surge in Alaska. Five states — Iowa, Oklahoma, Alaska, Vermont, and New Hampshire — have seen COVID-19 cases increase 10 percent in the past 2 weeks.

That’s led to concerns about whether the colder weather is playing a role. Lower temperatures and rainy weather tends to drive people indoors, many of whom aren’t wearing masks.

“We’re always concerned that when the weather gets colder and more and more people go in, they spend more time indoors in close association with each other. That’s an environment in which respiratory viruses will spread” said Dr. William Schaffner, an infectious disease expert at the Vanderbilt University School of Medicine in Tennessee.

But Schaffner also said that COVID-19 cases had spiked in the months with warmer weather, too. In addition, the vaccine and infection-acquired immunity might make a difference this winter.

“We’re not sure because we’ve certainly had brisk transmission now during the past two summers, 2020 and 2021,” Schaffner told Healthline. ““I think that’s a very reasonable hypothesis. We’re just going to see how this evolves going forward.”

Dr. Ali Mokdad, a professor of epidemiology and global health at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, says there are two factors behind the uptick in cases in states already experiencing cooler temperatures.

“The reason we’re seeing a spike in the cases in the North right now is because the Delta variant arrived in the North a little bit later than it did in the South,” Mokdad told Healthline. “So, Florida peaked before states like Michigan and Minnesota.”

“The weather also has a big part. And what you’re seeing right now in many of the Southern states is that the weather is so good right now that people can still eat outside and party outside. That’s helping them,” he said.

“The fact that it’s getting colder in the Northern states and people are moving indoors, that will work against them,” Mokdad said.

The IHME is projecting that the winter season could bring a reversal of the positive numbers we have been seeing with a moderate surge of cases again, although not like we saw last winter.

“At the national level, cases will start going up toward the end of November. It will peak sometime in January,” Mokdad said.

“In this coming surge, it will not reach the level that we’ve seen in summer, but it will go up,” he said. “Deaths and hospitalizations will also go up, but not proportional to the cases. It will not be what we saw last summer or winter because the vaccines are highly effective and more and more people are being vaccinated.”

Mokdad says holiday travel in the winter being added to the mix could exacerbate things.

“People travel. They get together for activities and social events” he said. “So, you put all of these together, we’ll see a surge this coming winter and cases will go up.”

Experts say the winter picture could also become more complicated if a new highly contagious coronavirus variant emerges. We’re already still dealing with the Delta variant.

Mokdad said getting more people vaccinated is key, and the mandates seem to be helping. Vaccinating younger children would also be a big help.

“The fact that children ages 5 to 11 may be allowed to get vaccinated, hopefully soon, that’s 6 to 7 percent of the population. That will help us have a higher pool of vaccinated people before the holidays,” he said.

“The booster will help. Even if you look at states that were early adopters, they may now be facing waning immunity and lower infection,” he said.

But one of the biggest complications could be the flu this winter.

“We expect a bigger epidemic of flu this year. The combination of flu admissions and COVID-19 admissions could put a lot of strain on our hospitals,” Mokdad said.