LEWISTON — Only about two months into the flu season — and the first one since the pandemic began without widespread COVID-19-related precautions in place — cases and hospitalizations have already far outpaced even pre-pandemic numbers.

As of the latest weekly flu surveillance report from the Maine Center for Disease Control and Prevention, there were 2,391 new lab-confirmed flu cases for the week ending Dec. 10. So far this season, there have been 5,812 cases.

That’s a remarkable increase in reported flu cases in Maine compared with the two years prior, when mask-wearing, social distancing and other public health measures were still in place.

According to the Maine Center for Disease Control and Prevention, flu cases are outpacing pre-pandemic numbers. Above, a sign at the entrance of Central Maine Medical Center in Lewiston in 2020 warns about the dangers of the influenza virus. Russ Dillingham/Sun Journal file

As of mid-December last year, there were about 230 reported flu cases. The year before, it was in the double digits. Mid-December numbers for 2019 and 2018, however, were on par with 2021 numbers and not even close to the number of cases, hospitalizations and deaths already reported this year.

That number is also likely an undercount, since not every person with flu gets tested.

“We’re seeing, you know, across the board, an increase in upper respiratory infections, whether it’s flu, RSV, COVID, which a lot of that is not surprising,” said Dr. Michael Stadnicki, a family medicine doctor at Central Maine Family Practice in Lewiston.

“As the weather gets colder, viruses tend to thrive,” he said. People tend to stay indoors. There’s more traveling and close gatherings for the holidays. These are all ways for viruses to easily spread, especially when people return to school or work after Thanksgiving, for example.

“So the generalization of ‘we expect to see an uptick right now’ is absolutely appropriate and is very much in keeping with every year,” Stadnicki said.

There are many reasons and theories for why this flu season is shaping up to be so severe. While it is difficult to impossible to say for sure why this flu season is more severe until researchers have more data, the fact that many people — especially children — have not really been exposed to flu and other respiratory viruses, such as respiratory syncytial virus or RSV, over the past few years probably plays a significant role, some clinicians and experts have said.

“Wearing a mask for two years, you know, we aren’t exposed to viruses. We were able to decrease the spread,” said Heather Nadeau, the Emergency Department nursing director at St. Mary’s Regional Medical Center in Lewiston.

She said that in her view it would be reasonable to assume that without those exposures, a person’s immune system could be more susceptible to catching the flu.

And even if clinicians and public health experts had expected to see a surge in cases this season, it is still flooding emergency departments, urgent care centers and primary care physicians’ offices with sick patients. Which is nothing to say of the other viruses still circulating, especially COVID-19 and RSV.

“We’ve done a really good job controlling COVID where yes, some people are still getting sick, just like they’ll always still have some people that are still getting really sick,” Nadeau said. “But our patients that are coming in with COVID have a lot less severe symptoms than our patients coming in with influenza right now.”

Since the pandemic began, St. Mary’s Urgent Care in Auburn sees on the order of 70 to 90 patients in a 12-hour day, many of whom present with symptoms of an upper respiratory infection, Nadeau said. And with only seven patient rooms and the necessary cleaning between patients, wait times can add up.

Stadnicki said at this moment it’s particularly important for people to take care of themselves — getting enough sleep, drinking plenty of water — and follow mitigation strategies like regular hand washing and staying home when sick.

“For the last few years, we haven’t had the same circulations of many viruses, flu being a big one of those,” Stadnicki said.

That, and what he said has been a “slow uptake” in flu vaccinations, may also be fueling this wave in cases.

According to the federal CDC, in Maine as of late November to early December, 41% of children 6 months to 17 years old had received a flu vaccine and about 47% of adults 18 years and older.

While the adult vaccination rate as of December 2019 is not too different from this year’s, at about 48%, vaccination among children is down significantly this year. As of Nov. 30, 2019, 51% of Mainers under the age of 18 were vaccinated against the flu, a difference of 10 percentage points compared to this year.