Feb. 27, 2025 – It’s been a dynamic flu season. Rates have been up and down more than once, and waves are likely to continue as influenza B prepares to make its regular appearance. And politics are stirring up questions about what’s ahead for the 2025-26 flu season.
Whether or not you’ve been vaccinated or you’ve already had the flu, all of this matters to you – here’s why.
1. The end of flu season is still months away.
That means if you haven’t had a flu shot yet, it’s still recommended to get one.
The variants circulating this year mean that getting a flu shot – even this late in the season – will provide important protection against serious complications, the likes of which have already sent hundreds of thousands of people to the hospital this season. An estimated 19,000 people, including 86 children, have died of flu so far.
Even though CDC data suggests flu cases may have peaked, rates are still really high. More than 1 in 4 flu tests are coming back positive, and influenza A strains are still predominant.
“Influenza season is composed of both influenza A and influenza B,” said Jonathan L. Temte, MD, PhD, an epidemiologist and professor of family medicine and community health at the University of Wisconsin. “Influenza B usually follows influenza A.”
“Although we have likely had our peak of influenza A in the U.S., 40% to 45% of influenza A cases are yet to come,” Temte said. “Because the vaccine protects against both influenza A and B, getting vaccinated now will protect one over the remaining one to two months of influenza season.”
If you’ve already had the flu, you could still catch it again, especially since it’s still widely circulating. And it’s not just a matter of possibly having influenza A and then later getting infected with influenza B.
“My research team has reported on a child becoming ill with influenza A (H3N2) twice in the same season,” Temte said. “While we are still in the influenza season, I recommend getting vaccinated, even if one has already had a case of influenza.”
2. Despite high flu cases, vaccine this season looks overall like a good match.
Early season laboratory testing by the CDC suggested this year’s flu vaccine was 100% match for the strain influenza A (H1N1), which accounts for 48% of cases this year, and a 100% match for influenza B, which accounts for just under 3% of cases so far. For targeting influenza A (H3N1), which makes up 49% of cases so far, the CDC said the vaccine is a 51% match.
“If you do the math, we end up with greater than 75% match,” Temte said.
He also noted that while it may seem like the vaccine isn’t very effective this year because so many people are getting the flu or being hospitalized, the other factor to keep in mind is how many people actually got a flu shot. As of Feb. 1, about 36.5 million doses of flu vaccine had been administered in pharmacies for adults, and 20.6 million were given in doctor’s offices. That’s 702,000 fewer doses and 4.2 million fewer doses, respectively, than were administered by the same time last year, according to the CDC.
“This year we have seen rather poor influenza vaccine coverage across the nation,” Temte said, “and this likely ties into the big uptick in cases and hospitalizations.”
Vaccines are better at preventing serious illness than mild illness. “On average, influenza vaccines are about 40% effective in preventing laboratory confirmed, respiratory infections in individuals seen in clinical settings,” Temte said. “They typically have much higher effectiveness for things that matter a lot: hospitalization, ICU admission, ventilatory support, and death.”
3. Flu strains for next season’s shots are in limbo.
Usually around this time, an advisory committee of influenza experts meet to advise the FDA on which flu strains should be targeted in next year’s formulation of the flu vaccine. The flu, like COVID, is always evolving, and scientists study those changes and predict which ones will be widely circulating next season. It takes months to manufacture flu vaccines, so the process starts well beforehand.
But on Wednesday, advisory committee members were notified that the scheduled meeting was canceled, multiple media outlets reported. Usually each year, flu manufacturers must get a supplemental approval from the FDA for changes to flu vaccine formulations designed to optimize them against strains for the upcoming season.
The World Health Organization will hold a similar flu shot formulation meeting on Friday, and STAT News reported that U.S. representatives from the FDA and CDC will participate.
The FDA’s website still advises people to get flu shots and states: “Flu viruses can change from year to year, so the vaccine is updated every year to protect against new flu virus strains that are expected to circulate and cause illness in the U.S. The FDA plays a key role in making sure flu vaccines are safe, effective, and of high quality.”
However, the webpage says the content is current as of Nov. 19, 2024, which is prior to the transition to the administration of President Donald Trump, who has called for sweeping changes to the nation’s health agencies.
