Massachusetts Faces Severe Flu Surge As New Variant Spreads

Massachusetts, along with much of the United States, is grappling with a flu season that has arrived with a vengeance, driven by a new and particularly aggressive strain. As of January 6, 2026, the state is experiencing a sharp, unusually fast-moving surge of flu illnesses, with cases and hospitalizations climbing to levels that have both doctors and public health officials on high alert. Emergency departments are filling up, pediatric units are seeing more young patients with serious complications, and the numbers suggest the worst may not be over yet.

According to the Massachusetts Department of Public Health, the state has recorded 33 influenza-related deaths so far this season, including four children. The share of visits to health care providers for flu-like illness jumped to 11.8 percent at the end of December 2025, up from 7.6 percent just a week before. Emergency room visits resulting in hospitalization for influenza rose to 9 percent—nearly double from the previous week and triple the rate from the same time last year. "It really did feel like a switch flipped," Dr. Zachary Binder, an associate professor of pediatrics at UMass Chan Medical School, told The Boston Globe. "We went from seeing hardly any flu to over half the patients in the emergency department being flu positive."

The culprit behind this surge is a new variant of influenza A, known as H3N2 subclade K, or simply subclade K. This mutated strain appears to spread more quickly than its predecessors and may be better at evading immunity built up in the community, according to both state and national health experts. The Centers for Disease Control and Prevention (CDC) has reported "very high" flu activity in more than half the states, including Massachusetts and Michigan, where hospitalizations and outpatient visits have soared. Nationally, the CDC estimates there have been at least 11 million illnesses, 120,000 hospitalizations, and 5,000 deaths so far this season, with 94 percent of tested flu cases being type A (including subclade K) and about 6 percent type B.

Symptoms of the flu this season are hitting hard and fast. People of all ages are reporting fevers as high as 104 or even 105 degrees Fahrenheit, persistent coughs, severe body aches, sore throats, and extreme fatigue. In children, the illness can also bring diarrhea and nausea, and some people have experienced a loss of taste and smell—a symptom more commonly associated with COVID-19 but not unheard of with influenza. Dr. Stuart Ray of Johns Hopkins University School of Medicine explained to TODAY.com that the symptoms can last from a few days to two weeks, with fatigue and chills often coming first, followed by fever, aches, and respiratory symptoms.

Pediatric specialists in Massachusetts are particularly concerned about the severity of complications in children this year. Dr. Vandana Madhavan, clinical director of infectious disease at Mass General Brigham for Children, described treating patients with acute necrotizing encephalopathy, a rare but serious complication of influenza that can cause sudden changes in mental status, difficulty speaking or eating, and even trouble breathing. "This is one of those seasons where everything is lining up in the wrong direction," Madhavan said to The Boston Globe. "It’s hard to say when our peak is going to be, and in some years, we see a second peak."

From November 1, 2025, through January 6, 2026, Mass General Brigham recorded 11,612 confirmed cases of Influenza A across its hospitals. But the actual number of infections is likely higher, as not everyone with flu symptoms seeks testing or medical care. In Michigan, the surge has been similarly dramatic, with 8,805 patient visits and 117,000 outpatient visits for influenza-like illness as of December 20, 2025, and more than 1,100 hospitalizations since October, according to the state's Flu Focus report.

Several factors are fueling this year's intense outbreak. The new subclade K variant is not only more contagious but also only a partial match to the current flu vaccine. Each year, scientists must predict which strains will circulate and develop vaccines accordingly—a process that sometimes misses the mark. Dr. Larry Madoff of the Massachusetts Department of Public Health acknowledged, "Even though the circulating strain is not a perfect match for the vaccine, a vaccine is far better than no vaccine."

Yet, vaccination rates have dropped. Only about 34 percent of Massachusetts residents have received a flu shot so far this season, compared to roughly 40 percent last year. Experts cite a mix of pandemic fatigue, reduced routine care visits, lingering skepticism about vaccines after COVID-19, and a general underestimation of influenza’s severity as reasons for the decline. Dr. Madhavan urges, "Now is the time, if you haven’t gotten vaccinated, to get vaccinated, to get some protection on board. And I would say that for COVID as well."

In response, Boston officials have opened six additional free flu vaccination clinics as of January 6, 2026. Hospitals are also tightening infection control measures: Brown University Health now requires surgical masks or N95s for all patients, visitors, and staff at its Massachusetts and Rhode Island locations, while Mass General Brigham implemented similar policies the previous week. These steps reflect a broader concern about overlapping respiratory viruses and high rates of hospital infections.

Doctors stress that most healthy adults recover from the flu within five to seven days, though symptoms like fatigue and coughing can linger. The incubation period for influenza A is typically one to four days, and people can be contagious starting about 24 hours before symptoms appear. Children, in particular, can shed the virus for 10 days or more, increasing the risk of spread in schools and childcare settings.

For home care, Dr. Madhavan recommends aggressive hydration (think popsicles and electrolyte solutions), controlling fever with ibuprofen or acetaminophen, and using honey to soothe coughs in children older than one. Parents are urged to watch for signs of dehydration, difficulty breathing, persistent high fever, or lethargy—and to seek medical care promptly if symptoms worsen. "There are treatments available, and the earlier those treatments are started, the more beneficial they are," Dr. Madoff advised. "For the vulnerable populations like young children, older adults, those with underlying medical conditions, those with respiratory issues or cardiovascular issues, Tamiflu and other treatments can be lifesaving."

While COVID-19 activity in Massachusetts remains relatively low compared with influenza as of early January 2026, health officials caution that seasonal waves can overlap. Their message is clear: get vaccinated, stay home when sick, wash hands frequently, and seek care early if symptoms worsen. As the state braces for what could be a prolonged and severe flu season, the urgency to act—and to protect the most vulnerable—has rarely been greater.