The number of influenza cases in the United States has significantly increased in December 2024, following the most severe flu season since 2018, according to the Centers for Disease Control and Prevention (CDC). The CDC reported that over 3,100 individuals died from influenza-related complications in the year ending August 2025. While it remains unclear whether this surge indicates a greater total of flu cases for the season or simply a clustering of cases in December, the situation has raised concerns among health officials.
As of December 20, 2024, there have been an estimated 7.5 million influenza cases and 81,000 hospitalizations in the US. This represents a 25% increase in cases compared to the previous week. The increase has affected 32 states, which have reported “high or very high” levels of flu illnesses.
Epidemiologist Jennifer Nuzzo from Brown University emphasized the importance of vaccination. “The bottom line for people is that if they haven’t gotten vaccinated against the flu, they should get vaccinated, particularly young kids and older adults,” Nuzzo stated. This advice is particularly crucial following the 2024-2025 flu season, which resulted in 279 pediatric deaths, the highest number recorded during a seasonal influenza epidemic.
The current spike in cases correlates with the emergence of a new variant known as subclade K. This season has also started earlier than usual in Europe, leading to “high or very high influenza activity” in December. The CDC noted that while the flu season is ramping up, the public’s response to vaccination may be impacted by recent developments.
At the beginning of December, approximately 130 million flu vaccines had been distributed in the US, which is 13 million fewer than at the same time last year. Nuzzo expressed concern regarding the reduction in vaccination efforts, particularly given the severity of the previous flu season. “It’s completely incredulous to me that after experiencing the worst flu season for kids on record, we could head into this flu season with anything but a robust plan to encourage people to get vaccinated,” she remarked.
Some residents may be hesitant about the effectiveness of the current vaccine against the new variant. Nuzzo cautioned that while the protection offered may be lower, it is still likely to provide significant benefits. “It may protect you less, but it’s likely still going to give you some important protection,” she explained.
An additional point of concern is that many individuals may not be aware they can obtain at-home flu tests from pharmacies. Nuzzo noted that early treatment is vital for those who test positive, as medications are most effective when administered shortly after symptoms begin.
As the flu season progresses, health officials continue to stress the importance of vaccination and early intervention to mitigate the impact of this potentially severe season.
