Emerging evidence indicates COVID-19 is a seasonal virus that thrives in colder weather like flu and other coronaviruses, Wooley explained. Compounding the problem, Ohio is far from reaching herd immunity, and many unvaccinated Americans plan to travel and gather over the holidays.
The beginning of another wave?
Before Thanksgiving, Ohio and the Dayton region began seeing an uptick in cases and hospitalizations, undoing much of the progress made since the recent peak in September.
Ohio Department of Health Director Dr. Bruce Vanderhoff said Tuesday it’s difficult to predict COVID-19 patterns, but said the recent numbers do not bode well.
“We are heading into the winter with very high levels of disease transmission,” he said. “And over the last couple of weeks, a definite upturn in the number of cases and the number of hospitalizations. So essentially we’re heading into the winter already in a surge.”
In the weeks leading up to Thanksgiving, the number of patients admitted to Kettering Health hospitals with COVID-19 nearly doubled, said Dr. Jeffrey Weinstein, patient safety officer at Kettering Health. In the three weeks between Nov. 2 and Nov. 23, statewide hospitalizations for COVID-19 increased by 40%.
“The severity of these COVID-19 illnesses is very high, and we are unfortunately seeing many deaths,” he said. “This is tragic as these deaths are largely preventable by the widely available vaccines And the upcoming Thanksgiving travel poses a major risk of spread for both COVID-19 and influenza.”
At this point in the pandemic, the majority of hospitalizations and deaths are among the unvaccinated. Statewide this year, about 95% of those hospitalized with COVID-19 and 95% of those who died of COVID-19 were not fully vaccinated. Regional COVID-19 hospitalizations have largely been unvaccinated people, hovering at around 87% of COVID patients in recent weeks, according to the Greater Dayton Area Hospital Association.
Premier Health centers have seen a similar increase in COVID hospitalizations as the rest of the state in recent weeks, said Dr. Roberto Colón, chief medical officer at Miami Valley Hospital.
“Unfortunately, there is indeed concern about another significant spike again if we are not careful,” he said. “The best ways to help avoid further increase is to continue to increase vaccine use and follow mask-wearing recommendations.”
How cold weather affects the virus
Respiratory viruses tend to transmit better in weather that’s cooler and less humid, Wooley explained. She pointed to studies that show the COVID-19 virus particle survives longer in cooler temperatures.
“So it’s a matter of the virus particle structure being more stable in the cooler temperatures,” she said. “And also, if you look at people’s susceptibility in their lungs, in this winter weather where it’s again cooler and drier, even their lungs can become a little bit more dry and more vulnerable to viral infections.”
Other coronaviruses that cause common colds that have been studied for years have seasonal patterns.
“So it’s very likely that this one will have the same pattern, and the data is emerging that it is fitting that same seasonal pattern,” Wooley said.
But like other viruses, COVID-19 is present year-round. And it reared its ugly head this summer. Wooley explained there were a number of factors that fueled that surge, which was still smaller than last winter’s peak.
“After over a year of lockdowns, a loosening of the social distancing guidelines and larger gatherings of people contributed to the surge. The more contagious Delta variant came on the scene and made younger people sicker than the original. Although the vaccine was available to everyone by summer, there were many people refusing the vaccine (and they still are),” she said.
How traveling, gathering could play a role
Thanksgiving travel rebounded this year. Over 53 million people were predicted to travel for the Thanksgiving holiday, up 13% from last year, according to AAA.
While experts said it’s safe for most fully vaccinated families to gather, they warned against unvaccinated people traveling and gathering together. But according to a Kaiser Family Foundation poll from October, only 7% of unvaccinated adults said they won’t travel for the holidays due to the pandemic or avoid large gatherings (12%).
The large number of people gathering indoors in the winter from different households, especially people from far away, compounds on the cold weather factor to spread respiratory viruses at higher rates, Wooley said.
“The more confined spaces with less airflow, there’s a higher chance of transmission and susceptible people may breathe in a higher dose,” she said.
Not at herd immunity
Until a population acquires enough immunity from a virus, outbreaks will continue.
“There’s still a lot of transmission,” said Sara Paton, an epidemiology professor at Wright State University. “And from what we’ve seen from other countries, it looks like you need to have 90% or more to really see COVID start to decrease significantly. I also think we have waning immunity. So even those that are fully vaccinated, if they haven’t gotten their booster, they’re not going to be as immune against COVID as they were a few months ago.”
Only about 52% of Ohio is fully vaccinated against COVID-19, and some area counties lag behind. Darke County is about 35% fully vaccinated, Preble County is about 37% vaccinated, Champaign County is about 40% vaccinated and Miami County is about 43% vaccinated.
“Given what we have learned about COVID so far, it is unlikely that we will reach herd immunity anytime soon,” Paton said. “New variants, vaccine hesitancy, waning immunity and human factors all play into this. However, the vaccines have shown to be highly effective at preventing hospitalizations and deaths. It is more realistic to expect that increased vaccination rates will reduce the severity and prominence of the disease, making the virus easier to live with.”
Ending the spread of the virus is one way to end the pandemic and return to normal, Paton said.
“But another way of ending the pandemic is to prevent severe disease and death,” she said.
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