Flu Cases Rise Significantly Across the Country

Recent data from the Centers for Disease Control and Prevention (CDC) indicates a troubling surge in flu cases nationwide, with some regions reporting record numbers. As of December 20, the CDC estimates that there have been around 7.5 million flu cases this season, alongside at least 81,000 hospitalizations and roughly 3,100 deaths, including eight pediatric fatalities.

The CDC has identified 32 jurisdictions exhibiting “high” or “very high” flu levels, a notable increase from only 17 the previous week. These jurisdictions encompass all 50 states, some territories, as well as the District of Columbia and New York City.

In New York State, health officials reported approximately 71,000 flu cases during the week ending December 20, marking the highest weekly total since tracking began in 2004. Additionally, over 3,600 flu-related hospitalizations were recorded that week.

Massachusetts is also facing high flu activity, with Boston noting a 114% rise in cases, particularly among children. A school in Minnesota opted for online learning ahead of Christmas due to rising flu cases, with the state documenting 113 flu-related hospitalizations in 2025—more than double the previous year’s figures.

Experts are increasingly worried about this flu season, particularly due to a new subtype of influenza A, H3N2, which is spreading rapidly. The CDC noted that out of 2,086 flu-positive samples collected between December 13 and 20, 2,029 were influenza A. Further analysis revealed that nearly 92% of subtyped samples were H3N2.

Jesse Bloom, a scientist studying viral evolution, explained that slight modifications in the virus’s structure might make it more difficult for people’s immune systems to detect it. This strain has historically been responsible for severe flu seasons, particularly among older adults.

Vaccination rates have also declined this year, with the CDC reporting approximately 130 million doses administered nationwide. Richard Webby, a director at the World Health Organization’s Collaborating Centre for the Ecology of Influenza in Animals and Birds, mentioned that although there’s concern about a potential “H3N2 mismatch,” the vaccine’s effectiveness against H1N1 and flu B appears promising. Preliminary data from the UK suggests that vaccinations remain effective in preventing severe illnesses, especially in children.

Bloom emphasized the importance of getting vaccinated, particularly for those in high-risk categories. While the vaccine can’t completely prevent infection, it can significantly reduce the risk of severe outcomes.