With flu returning and COVID cases rising, could Connecticut see ‘twindemic’ this winter?

One Connecticut doctor said he prescribed Tamiflu this week for the first time since the start of the COVID pandemic.

One Connecticut doctor said he prescribed Tamiflu this week for the first time since the start of the COVID pandemic.

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This week, Brooks Walsh prescribed Tamiflu for the first time in nearly two years. The last time was February, 2020, just as the coronavirus pandemic was beginning.

“We haven’t had an occasion to prescribe it since then,” said Walsh, an emergency room physician at Bridgeport Hospital.

Influenza was largely unseen in Connecticut for the past two years, researchers speculating that mask use, better hygiene practices and social distancing kept the virus at bay.

“People aren't entirely sure why we haven't had influenza since March of 2020,” Walsh said.

While flu is no longer considered at bay, there have been few cases so far this season.

Ulysses Wu, head of infection prevention at Hartford HealthCare, said his health system had five patients this week admitted with severe flu symptoms.

“It’s following a normal curve, it’s just the curve is a lot lower than previous years,” Wu said. “I do suspect that it’s going to increase, probably peaking sometime in February.”

Rick Martinello, head of infectious disease at Yale New Haven Health, said his health system “went about a year-and-a-half” with only one flu case.

“We did have a returning traveler from the Middle East, who was here, like, a day, developed a fever, found to have flu, and came into one of our emergency departments,” Martinello said. “One case, and that was clearly imported from outside the United States.”

Last year, before COVID vaccinations were widespread, there was some concern of a “twindemic,” with flu and the coronavirus possibly overwhelming already strapped hospital resources, Walsh said.

“There was a lot of concern last year around this time that influenza would come back,” he said. “For whatever reason, that just didn't happen last year.”

That “twindemic” did not occur, but there is concern that it could happen this year. COVID cases are on the rise again in Connecticut, with coronavirus-related hospitalizations increasing to 414 by Thursday this week.

“Having influenza come through right now presents another challenge,” Walsh said.

It might prove to be a particularly bad flu season, experts say. There are two types of flu, known as “A” and “B.” The B-type influenza typically presents with less severe symptoms.

“B just generally doesn’t cause the same widespread stress on the medical system and mortality and morbidity among patients,” Walsh said.

The flu seen primarily this year has been the A-type, or H3N2.

“It looks like this year it’s mostly A,” Walsh said. “The much documented 1919 flu was an A. The 2009 epidemic was an A as well.”

There are other reasons to suspect a particularly bad flu season this year. First, Martinello said, because flu has been nearly absent for so long, nobody has had the opportunity to become immune to it.

“Population immunity is less than what it would typically be,” Martinello said.

Also, flu vaccines may be less effective this year. Each of the two strains of flu present different variants each year, and the vaccines must be tweaked to be effective against the specific variant that is prevalent.

But because the incidence of flu has been so sporadic, it will be difficult to tailor vaccines to match the flu strain.

“Every year scientists try and predict what strain will be most prominent in the coming year,” Walsh said. “You need at least six months lead time to produce the vaccine, so it’s a bit of a guess, and there can be misfires.”

“There are concerns that the H3N2 strain is a little bit tougher to get a good fit with the vaccine,” he said.

Flu vaccines, Martinello said, are often about 60 percent effective, “which is good, but not great.”

“Some years we see a vaccine where it's only about 10 percent effective,” he said. “That's just because there's a mismatch between what's in the vaccine and what's circulating. There's a higher risk this year that there will be a mismatch.”

By March 2020, when the COVID hit, there had been 68 deaths from flu in Connecticut, and though coronavirus-related deaths quickly outpaced even the worst flu season, influenza cases did contribute to stress on hospital resources.

“Back in late 2019, early 2020, we were having a rough flu season. The system got stressed,” Walsh said. “That’s what made the thought of a new epidemic so daunting.”

“There’s a lot of people hypothesizing about how it will work out,” he said.