Will COVID become the next seasonal illness?

Michigan’s annual flu season spans most of the cold months of the year, with the peak typically occurring between December and February.

As the state ends its second summer season with the coronavirus active in the community and heads into its second fall and winter with the virus, it begs the question: Will COVID become the next seasonal illness?

Seasonal viruses are those that tend to circulate and peak during specific seasons of the year. In temperate climates like Michigan, viral infections like the flu usually increase during the colder months due to a variety of factors including increased number of people indoors, reduced levels of vitamin D without light sufficient solar and immune system suppression in colder conditions.

While behavioral factors during the colder months produce ideal conditions for viral transmission, doctors say it is too early to predict future seasonal patterns with the coronavirus.

“Anyone who says it’s a seasonal virus right now, I think they’re getting ahead of themselves,” said Dr Liam Sullivan, infectious disease specialist for Spectrum Health in Grand Rapids.

“This virus has not shown any seasonality at this point, and I think that’s for several reasons.”

Related: The flu practically disappeared last season; this season, that might not be the case, Michigan doctors warn

For starters, Sullivan said, the vast majority of people on the planet still lack some level of immunity to the virus, either through vaccination or natural infection. While about 70% of the US population has received a first dose, other countries have much lower rates, many due to less access to vaccines.

The virus has so many vulnerable targets to pursue year round that it does not require ideal conditions to spread. This is evident by the significant epidemics throughout the four seasons and in the northern and southern hemispheres.

Another factor is the continued mutation of the coronavirus into more infectious strains like the delta variant, which allows it to continue to spread at a high rate throughout the year.

“This virus is kind of writing its own script and doing the things it wants as it goes,” Sullivan said. “There are things we know that increase the propensity for its spread, but there are still things we don’t quite know about its behavior yet.”

“Is it possible that it turns into a seasonal virus?” Of course it is. But I think it’s too early to tell and I don’t think there has been a seasonal pattern for this virus yet. “

Dr Christopher Ledtke, infectious disease specialist for Munson Healthcare, echoed Sullivan. Instead, he said, the coronavirus turns out to be more “based on flare-ups.”

As Michigan saw a significant increase in new COVID cases in the spring of 2021, even as temperatures warmed in the Midwest, other parts of the country were reporting plateaus and declines in new cases.

Fast forward to summer, and the south has been the main region for new COVID cases since early July, although weather conditions are not ideal for the transmission of other seasonal viruses.

“You have local breakouts in specific parts of the country and different parts of the world, on the north side of the equator, on the south side of the equator, unrelated to the season that is going on,” Ledke said. “I wouldn’t consider this a seasonal virus in any capacity. It is based on local pushes, slightly related to the new variants introduced in the region.

This does not mean that there are not factors associated with certain seasons that will favor the spread of the coronavirus. For example, Sullivan said it would be naive to ignore that schools play an important role in increasing transmission during the months other than summer. The same can be said of the annual number of influenza.

Related: 614 people infected in 106 new outbreaks of COVID in Michigan schools, according to September 27 report

“The main theme of this time of year is that people are more together and closer to each other and that they are in potential settings where the virus can more easily spread from person to person. other, ”Sullivan said.

Dr Laraine Washer, clinical professor of infectious diseases at the University of Michigan School of Medicine and epidemiologist for Michigan medicine, said “we do not have enough longitudinal experience with COVID to predict seasonality with certainty. for the year or two to come “.

Washer expects COVID to eventually evolve into an “endemic seasonal respiratory virus,” meaning it will be a constantly present virus circulating in pockets of the world’s population.

This reflection is comparable to 89% of the more than 100 immunologists, infectious disease researchers and virologists surveyed by the international journal Nature. About 60% said SARS-CoV-2 was very likely to become an endemic virus, compared to 29% who said it was likely, 5% said it was unlikely and 6% said it was there was not enough evidence to estimate.

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