Local doctors say masks and social distancing kept last year's flu season especially quiet, but the flu is back this year with a vengeance, along with other seasonal respiratory viruses.

"We've been seeing flu in small numbers ever since a little bit before Thanksgiving. But definitely in the past two weeks we've seen a significant uptick in flu cases," said Dr. Magna Dias, the Regional Medical Director for Inpatient Pediatric Services at Yale New Haven Children's Hospital.

Dias says she has not seen any so-called "flu-rona" cases yet – the hospital does have patients who are fighting COVID at the same time as another respiratory infection.

"A lot of times when we do see kids that have more than one illness at a time, it's not uncommon for those kids to be the ones who are more likely to end up in the ICU," said Dias.

She says multiple respiratory viruses circulating in one person can put a strain on the body's immune system.

"So if you have an infection that you're fighting off, your body is so focused on fighting off that infection, that sometimes if you're exposed to another infection, it's just easier for that infection to take control," said Dias.

She says multiple respiratory viruses circulating in the community is taxing on a health care system that's already seeing staffing shortages.

"It's really straining our capacity to be able to take care of people that come into our emergency rooms and pediatric offices, because we only have so many people," she said.

Only about half the state got vaccinated against flu this year, a little lower than average.

"All these other viruses like RSV and the common cold do spread by contact, so its super important to wash your hands, for that reason," Dias said.

The Centers for Disease Control and Prevention said flu season usually peaks in February and can continue until May.