New Jersey is experiencing a sharp rise in flu activity, with confirmed cases nearly tripling this November compared to the same period in 2024, according to newly released data from the state Department of Health. Coupled with declining vaccination rates and the emergence of a mutated H3N2 strain, public health officials warn the state may be heading into a severe flu season.
Between Nov. 1 and Nov. 29, New Jersey reported 4,366 laboratory-confirmed flu cases. During the same period last year, the state recorded just 1,539 cases. Nearly 20 percent of this November’s cases were in children ages 0 to 4. By the end of November, four cases were classified as severe, though no flu-related deaths have been reported in New Jersey so far this season.
Declining vaccination rates are a major concern. CDC data shows only 38.1 percent of New Jersey children ages six months and older were vaccinated for the flu by the end of November this year, down from 40.3 percent at the same point in 2024 and continuing a multi-year decline.
Adding to the concern is the rise of an Influenza H3N2 mutation known as “subclade K.” The variant has undergone seven mutations and differs significantly from strains included in this year’s flu vaccine.
Although this year’s vaccine does not cover subclade K specifically, health experts say it still offers meaningful protection against severe disease.
The U.S. recorded 287 pediatric flu deaths last season—the highest number since the 2009–2010 H1N1 pandemic. Five of those deaths occurred in New Jersey. CDC data shows that 89 percent of the children who died nationwide were not vaccinated.