After a difficult and unprecedented flu season, doctors and health officials are bracing for another wave of fever, misery and respiratory distress.
In the United Kingdom, health officials are warning of an early rise in flu levels among children and young adults. In Japan, health officials recently declared a flu epidemic and closed schools after experiencing an unusually high number of flu cases early in the season.
What does that mean for the United States?
Typically, flu cases begin to increase in November, along with RSV (respiratory syncytial virus) and enteroviruses, and peak in February. But the chaos of job cuts at the Centers for Disease Control and Prevention and the government shutdown could make it difficult to know how the virus is developing this fall, experts fear.
The CDC’s last flu report for the US was for the week ending September 20, when there was minimal activity.
Angela Rasmussen, a virologist at the University of Saskatchewan, is concerned that the CDC could limit flu surveillance, leaving the United States blind to the scale and scope of flu outbreaks.
“Everything from outreach campaigns to more logistical efforts to distribute vaccines” could be affected, Rasmussen said. “That information may simply not be available, so it will be very difficult to coordinate a national response,” he said.
Last year’s flu was tough. According to the CDC, there were about 1.1 million flu-associated hospitalizations, the highest rate in 14 years. And there were the highest number of doctor visits for flu-like illnesses in more than a decade.
An estimated 38,000 to 99,000 deaths were associated with the 2024-2025 flu season, according to a preliminary CDC assessment. For children, it was one of the deadliest years ever recorded: 280 children died from the flu. At least three of those children died in June and July, a far cry from the typical flu season.
How bad will the flu be?
The flu is very difficult to predict and this year things are already looking a little different.
The CDC predicted in late August that this flu season will be milder than last year. However, there is a chance that some age groups could be severely affected, especially if people do not get vaccinated against the flu.
The main flu strains. Those currently circulating are similar to those that caused the serious outbreaks last season: H1N1 and H3N2 for influenza A, as well as for influenza B.
“It’s a little early to tell which strains will predominate this year’s flu season, but there’s certainly a risk that similar, highly virulent strains could circulate again this year,” said Dr. George Diaz, a member of the Infectious Diseases Society of America and chief of medicine at Providence Regional Medical Center in Everett, Washington. “This prediction of a moderate season could be wrong and it could be another severe flu season,” he said.
“We’re still in the early stages of the flu season in North America and it’s a little difficult to know for sure,” he added.
Even if someone got the flu last year, they will still be vulnerable to the new version because immunity wanes over time, especially in older people and immunocompromised people, experts say.
When is the best time to get a flu shot?
The tension is just one factor in how bad this year could be. Vaccine hesitancy and a weakened public health infrastructure in the United States could contribute to the spread of the flu.
“It’s going to be driven largely more by social and political changes than by virologically related changes,” Rasmussen said.
Last flu season, less than half of children were vaccinated against the flu, a decrease of more than 20 percentage points from the 2019-2020 season. This year that trend is expected to continue, Rasmussen said.
Dr. William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center, said it’s hard to know how severe this year will be in the United States, but it’s very unusual to have “two ultra-severe seasons in a row.”
So while the virus hasn’t changed much, getting vaccinated is the best way to protect yourself against the worst of the season.
“October is the ideal time to get vaccinated,” he said. “That should provide pretty reasonable protection during what we consider the flu season, from February to March.”
