New, more contagious strain of flu spiking cases in CT ahead of holidays. What you should know

Hartford Courant – Tuesday, December 23, 2025
By Kaitlin McCallum

After years of missed holiday parties, masks and pre-Christmas covid tests, many people are hoping to see this year’s annual traditions uninterrupted by illness.

But with the increasing spread of a new flu variant, doctors are still urging caution.

Connecticut has seen a spike in hospitalizations due to influenza in December, with an estimated 7,204 cases this season, according to DPH. The Center for Disease Control’s Weekly Influenza Surveillance Report, based on outpatient visits to health care providers, puts Connecticut’s flu activity in the high range, with nearby Delaware, Rhode Island and New York in the very high range.

In New York City last week, 6.67% of emergency department visits resulted in a flu diagnosis, with 24,607 laboratory-reported cases in the city as of Dec. 13.

Connecticut has also logged 4,765 cases of covid this season, causing just 0.7% of emergency department visits last week.

Nationally, the CDC reports more than 1,900 deaths from flu this year, including three children. It estimates 4.6 million people have gotten sick. In the past week, the new strain Influenza A H3N2, which has historically had a more severe impact on older people, has accounted for the majority of cases.

Dr. Ulysses Wu, infectious disease specialist and chief epidemiologist for Hartford HealthCare, said people should be worried about the flu this year – and every year.

“People should be worked up about the flu every year. It’s an issue every year. Last year was one of the worst years we’ve had in a very long time with an estimated 130,000 deaths,” Wu said Monday, noting that there are 40,000 to 50,000 deaths in an average year.

Those deaths, he said, are largely preventable with vaccinations – even if someone gets sick after getting the vaccine, it will lessen the symptoms and protect against severe disease that may lead to hospitalization or death.

“It’s like getting into a car accident without your seatbelt. You may not be able to prevent the car accident but it could be a lot worse,” he said.

The new strain responsible for the majority of cases in Connecticut, H3N2, is more contagious, Wu said, but should be treated as every other strain – with caution. And though the flu vaccine is not an exact match for H3N2, it doesn’t need to be, to provide protection.

“From a microbiological perspective, it is definitely different because the flu strains change every year. But what people are reading about this year – that the vaccine is not a match – it doesn’t really matter because flu strains are changing all the time,” Wu said.

For those that haven’t gotten the vaccine yet and are planning on heading to holiday parties and family gatherings, Wu advised getting the shot now, even though the full benefits of the vaccine typically take effect up to two weeks later.

“It will help a little bit and flu season runs through until May so they should absolutely get vaccinated. We encourage people to get vaccinated all the way through the end of the season,” Wu said.

People should also be cautious around those who are young, old, immune-compromised or have chronic illnesses. Hand-washing, mask-wearing and getting vaccinated are the best ways to protect yourself and others.

“If you haven’t gotten vaccinated and you’re going to be with people who might be vulnerable to getting sick, maybe avoid the gathering,” Wu said. “If you have to go, you’ll look weird – as everybody thinks you do – but you may want to wear the mask.”

For those that have symptoms, “we always tell people if you’re sick, don’t get anybody else sick … A lot of people who get the flu do OK but may spread it to someone who will not do OK,” Wu said.

If someone does get sick, they should get treatment immediately if they are immunocompromised, including of young or old age, have a chronic disease or cancer, because the risk of severe symptoms is higher and antiviral medications that may help must be started within five days of symptom onset, Wu said.

“They should get the diagnosis because it may not be flu. It could be covid or it could be RSV … those who may be at risk of complications should go,” Wu said.

Most importantly, “it’s not too late to get your flu vaccine and you cannot get the flu from your flu vaccine – it is impossible,” Wu said.

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