Record-breaking paediatric flu hospitalisations and deaths in Colorado highlight urgent need for increased vaccination amid low uptake and severe strains on healthcare services.
Colorado paediatricians are urging families to get flu vaccinations early after the state recorded back-to-back record levels of children’s hospitalisations in the past two seasons, a trend they say reflects both heavy viral circulation and persistently low uptake of the shot.
Colorado logged 1,169 hospital admissions of patients under 18 with flu in the 2025-26 season, the highest total since the state began tracking the figure. That season is due to end on Saturday, and the final count could rise slightly before the next flu season begins. The year before, Colorado also set what was then a record, with 856 paediatric flu hospitalisations.
The toll has also been severe in deaths. Eight children in Colorado died from flu complications this season, the highest number since the 2009-10 season, when a new swine flu variant spread around the world. In that earlier season, 12 children died, matching the deadliest year for the state since reporting began in 2003-04.
Dr Suchitra Rao, an infectious-disease specialist at Children’s Hospital Colorado, said the previous season was dominated by H3N2, a strain of influenza A that often causes more serious illness. She said the virus also picked up mutations that reduced the vaccine’s effectiveness, while vaccination rates fell, leaving fewer children with even partial protection.
Vaccination levels in Colorado remain well below what public health officials would like to see. About 37% of children aged six months to nine years got a flu shot last year, along with roughly 25% of older children and teenagers. Nationally, the Centres for Disease Control and Prevention said about 49% of children aged six months to 17 years were vaccinated.
The pressure on hospitals was substantial. Children’s Hospital Colorado said it treated more than 900 children with flu in the most recent season and about 800 in the one before that. Rao said the hospital was able to increase staffing and care for every child who needed a bed, but she warned that flu can be far more dangerous than many parents realise.
“Flu can kill. It’s not just something that gives you a mild runny nose and is inconvenient for a few days,” Rao said.
Kaiser Permanente also saw the strain on outpatient services. Dr Deniz Kolozs, associate medical director of paediatrics at the system’s Aurora Centrepoint location, said Colorado clinics had to add staff and spend more time co-ordinating with hospitals during the peak of last December’s respiratory season. She said low vaccination rates played a major role in the surge.
“We had doctors working overtime,” she said.
Children under five face the highest risk from flu, Kolozs said, with babies under six months particularly vulnerable because they cannot be vaccinated. She said young children’s smaller airways make breathing problems more likely, while dehydration can develop quickly and symptoms may be harder for parents to spot in children who cannot clearly describe how ill they feel.
Doctors also encourage pregnant women to get the flu shot, in part to pass some protection to their babies before birth. They recommend that people who spend time around infants be vaccinated as well, to reduce the chance of bringing the virus home.
The Colorado figures come against a broader backdrop of severe flu seasons across the United States. The CDC has said the last two seasons were worse than expected, with hospitalisation rates about 23% higher than the next-most-severe year and roughly double the median for the previous 16 years. In the most recent season, 193 children died nationwide, following 297 deaths the year before, which was the highest paediatric flu death toll recorded since at least 2004.
Rao said the most common reasons children end up in hospital are pneumonia and other breathing complications, whether caused directly by the virus or by secondary bacterial infection. Dehydration is another major concern, and a smaller share of children develop inflammation in organs while fighting the illness.
There is some reason for cautious optimism this year. Rao said the flu vaccine appears to be a good match for the strains now circulating. Even so, she and Kolozs both stressed that timing matters: it takes about two weeks after vaccination for the immune system to build protection, and waiting for a holiday window can leave families exposed if the virus starts spreading earlier than expected.
Antiviral medicines can also help, particularly when started in the first few days of illness, but Rao said the shot remains the strongest defence against severe disease. Her message to parents was simple: do not wait.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
