A new flu strain is raising concerns among health experts as winter approaches and millions prepare for holiday travel.
Scientists are tracking the H3N2 subclade K variant, which is genetically different from the strain included in this year's flu vaccine. This means the new variant could potentially escape immunity even for people who have received their flu shot.
"Because we as a community don't have as much immunity to it, more people are getting sick," said Catherine Troisi, an infectious disease epidemiologist at UTHealth Houston.
The variant was first spotted late in the flu season for the Southern Hemisphere. In the CDC's most recent data, the K subclade made up 56% of all H3N2 flu cases, which account for the bulk of people infected.
"The fact that we're seeing more H3 N2 overall means we're probably in for a rougher season," Troisi said.
While this strain does not appear to cause more serious disease or hospitalizations, Troisi warns that if more people get sick, there will inevitably be more hospitalizations overall.
Adding to concerns, fewer people may be getting their flu vaccine this year. More than 2 million fewer shots were given at U.S. pharmacies through October compared to last year, according to health information and research company IQVIA.
"Fewer people getting the vaccine means that there are going to be higher rates of flu infection because fewer people are going to be protected," said Asefeh Faraz Covelli, an associate professor at George Washington University School of Nursing.
The CDC recommends that nearly everyone 6 months and older should get the flu vaccine and says it's the best way to reduce the risk of getting sick.
Health experts are also monitoring norovirus, with positive tests doubling over the past 3 months according to the latest CDC data. There's no vaccine for norovirus, but doctors recommend washing hands thoroughly and frequently to help prevent it.
