The flu season in 2025 has proven to be a dynamic one, with flu rates fluctuating and expected to continue shifting as influenza B makes its usual appearance. Whether or not you’ve been vaccinated or have already had the flu, it’s important to understand the current state of the season. Here are three key updates on the ongoing flu season and what it means for you:
- The end of flu season is still months away.
Flu season typically lasts well into spring, so if you haven’t yet received a flu shot, it’s still recommended to get vaccinated. Although flu cases may have peaked, the current data shows that flu rates remain elevated. Getting vaccinated now, even late in the season, can provide important protection against serious complications, which have already caused hundreds of thousands of hospitalizations and deaths. So far, an estimated 19,000 people have died due to the flu, including 86 children.
Even though flu cases may have reached a peak for now, it’s important to note that more than one in four flu tests are returning positive, and influenza A strains continue to dominate. Jonathan L. Temte, MD, PhD, an epidemiologist and professor of family medicine, noted that influenza season consists of both influenza A and B strains, with influenza B typically following influenza A. He explained that while the peak of influenza A may have passed, about 40% to 45% of influenza A cases are still expected to occur. Therefore, receiving a flu vaccine now will still protect you through the remainder of the season.
If you’ve already had the flu, you could still be vulnerable to another infection. Some people, especially children, have been reported to suffer from multiple infections in a single season. Temte’s research team documented a case of a child who became ill with influenza A (H3N2) twice within the same season. Even if you’ve already had the flu, it’s wise to get vaccinated to ensure greater protection as the season continues.
- Despite high flu cases, the vaccine remains a good match.
Despite the high number of flu cases this season, the flu vaccine for 2025 appears to be a good match for the strains circulating. Early laboratory tests from the CDC revealed that this year’s flu vaccine was 100% effective against the influenza A (H1N1) strain, which accounts for nearly half of all cases, and against influenza B, which represents just under 3% of the cases so far. The vaccine was also a 51% match for the influenza A (H3N1) strain, which accounts for nearly half of the cases.
While the vaccine might not seem highly effective given the number of flu cases and hospitalizations, the low vaccination rates this season are a contributing factor. By February 1, about 36.5 million flu shots had been administered at pharmacies, and 20.6 million in doctor’s offices. These numbers are lower than the previous year, which has likely contributed to the uptick in flu cases and hospitalizations.
The flu vaccine is more effective in preventing serious illness than in preventing mild cases. In general, flu vaccines are about 40% effective in preventing laboratory-confirmed respiratory infections in clinical settings. However, they have much higher effectiveness when it comes to preventing hospitalization, ICU admissions, and death, which are the more critical outcomes of flu infections.
- Flu strains for next season’s shots are in limbo.
Flu vaccine development requires careful monitoring and prediction of which strains will circulate the following season. Each year, an advisory committee of influenza experts advises the FDA on which strains should be targeted in the vaccine formulation. However, the process of selecting flu strains and manufacturing vaccines takes months, so decisions need to be made well in advance.
This year, however, the advisory committee meeting, which was scheduled for late February, was canceled. This is unusual, as the committee typically meets to review data and decide on the best flu strains to target for the next season’s vaccine. The World Health Organization will hold a meeting to discuss flu vaccine formulation, and representatives from the FDA and CDC will be participating. The FDA’s website still advises people to get vaccinated, noting that flu viruses can change from year to year, making the annual flu vaccine crucial for protection.
While the uncertainty surrounding next season’s flu strains remains, the message is clear: flu shots are still important, and continuing to vaccinate during the current season will help mitigate the spread and severity of the flu in the coming months.
