Massachusetts Reports More Than 8,800 Flu Cases as New Variant Drives Surge

Massachusetts is in the midst of a severe flu season. Health officials rate flu activity as very high and severity high, underscoring the seriousness of the situation.

According to an NBC10 Boston report, the state recorded more than 8,800 flu cases in its most recent weekly report from Dec. 21 to Dec. 27, 2025. During the previous week, there were approximately 7,200 lab-confirmed cases.

The sharp rise in cases has been driving increases in emergency room visits, urgent care visits, and hospitalizations.

“It's very concerning,” said Dr. Larry Madoff, medical director for the Bureau of Infectious Disease and Laboratory Sciences at the Massachusetts Department of Public Health, in a statement shared with NBC10 Boston. “We think things are still on the way up in terms of flu activity, and the peak is not likely to be until late January or even February.”

One factor contributing to the surge in flu cases in the state is the emergence of a flu variant, subclade K. This variant originated abroad and is now circulating in the United States. While flu vaccines offer protection, this strain may partly evade immunity and accelerate spread.

Dr. Paul Sax, an infectious disease specialist at Brigham and Women's Hospital, told NBC10 Boston that many people coming into his hospital for flu evaluation are testing positive.

“There's a positive test rate as high as 10% in people coming in,” he confirmed.

Medical experts reiterate that vaccines tend to reduce illness severity and encourage vaccination to protect against complications. They emphasize staying home from school or work if you get sick and wearing a mask in public settings if you must go out to reduce the spread of the flu virus.