H3N2 developed after this season's vaccine was developed so it may not be as effective
- The flu is early this year, with cases reported throughout the U.S. and around the Western Hemisphere
- A new subvariant, H3N2, developed after this season's vaccine was formulated, which could affect its effectiveness
- Children were hard hit by the flu in Australia and other Southern Hemisphere countries this year
The flu is arriving a bit early this year, particularly the new H3N2 variant that's now being observed across the United States and elsewhere in the Northern Hemisphere.
Health reports indicate rising flu activity in numerous states, with increasing test positivity and respiratory illness visits in places like New York, Iowa, and New Hampshire, and outbreaks prompting school closures in some districts.Experts warn that flu activity is increasing in many regions across the U.S. and theres concern the season could be severe, similar to last years heavy H3N2-dominant season.
We are at the point now where were starting to see a sharp rise in flu cases. This is a few weeks earlier than we usually experience, but very much akin to what was seen in the Southern Hemispheres experience with flu during their winter, said Dr. Elizabeth Hudson, regional physician director of infectious diseases at Kaiser Permanente Southern California in a Los Angeles Times report.
Vaccine may not be as effective
The new variant officially H3N2 Flu A subclade K appeared toward the end of summer. That was months after officials decided which strains this falls flu vaccine would target, meaning the vaccine may not be as effective against the new subvariant as it is against others. However, datarecently released in Britain showed this seasons vaccines were 70% to 75% effective against hospitalization for children from the flu, and 30% to 40% effective in adults, which is within expectations, the U.S. Centers for Disease Control and Preventionnoted.
This suggests that influenza vaccination remains an effective tool in preventing influenza-related hospitalizations this season, according to the agency.
While flu rates remain low overall at this point, officials say the experience in other nations could indicate that the U.S. is in for a severe flu season. They note that Australia's season hit hard and early and was especially hard on children. Three flu-related pediatric deaths have been reported in the U.S. so far this season. During the last flu season, 280 children died from flu.
Early diagnosis of flu can help stave off the worst by giving those who are sick time to take antiviral medications such as Tamiflu. Three out of 5 children who died from the flu during the 2024-25 season never received antiviral medication.
What to watch for
Emergency warning signs of flu complicationsin children include trouble breathing; bluish lips or face; ribs pulling in with each breath; chest pain; severe muscle pain, in which a child may refuse to walk; dehydration, signs of which include no urine for eight hours or no tears when crying; seizures; fevers above 104 degrees that are not controlled by medication; fever or cough that improves but returns or worsens; and any fever in newborns younger than 12 weeks.
Posted: 2025-12-29 00:33:07















