Flu hospitalizations rise nearly 30% as US enters holiday season

Susana Sanchez, a nurse practitioner, administers the flu vaccine to Lozzie Barrera at CVS Pharmacy and MinuteClinic in Miami, Florida.

Joe Rydle | Getty Images

Flu hospitalizations rise nearly 30% in one week as prevalence of respiratory illness remains high in most parts of US

More than 11,200 people were hospitalized with the flu during the week ending Nov. 19, compared with about 8,700 patients during the previous week, according to data from the Department of Health and Human Services.

The flu is hitting emergency departments across the country unusually hard and early this season. Flu activity normally increases after Thanksgiving, but hospitalizations in early November were at a decade high.

Scientists and public health experts worry that the number of flu hospitalizations will rise even further after millions of people travel to see family and friends for Thanksgiving. Christmas is also just a few weeks away, providing another opportunity for the flu to spread widely.

Nearly 11 out of every 100,000 people have been hospitalized with the flu since the beginning of October, the highest level in a decade. More than 6.2 million people have been sickened this season, 53,000 have been hospitalized, and 2,900 have died. According to data from the Centers for Disease Control and Prevention.

“The fact that we’re already heading into the holiday season at this high level bothers me,” said Scott Hensley, a microbiologist and flu expert at Penn’s Institute for Immunology.

Hensley said the flu is hitting harder earlier this year because population immunity is probably at its lowest level in recent history. He said that the flu basically did not circulate for two years due to the masking and social distancing measures put in place during Covid. As a result, large herds A portion of the population didn’t get an immunity boost from the infection, so they may be more vulnerable to the flu this year than last season.

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Seniors and children under the age of five are the most vulnerable, with hospitalization rates nearly double the national average. A form of the flu that is more severe for the elderly is still in effect, meaning the US could be in for a tough season. According to the CDC, more than 60% of flu samples tested by public health laboratories were positive for the influenza A (H3N2) strain.

“This is a well-described phenomenon. H3N2 tends to have more severe effects on older individuals, resulting in more hospitalizations, ICU admissions, and deaths,” said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University.

Flu vaccines are generally not as effective against H3N2, although there is hope that this season may prove to be different. According to the CDC, most of the flu viruses tested are similar to the strains included in this year’s vaccine.

Vaccine efficacy data have yet to be published, but shots generally perform better when they are well matched to the circulating variant. Flu vaccine efficacy has ranged widely in past seasons, from 19% to 60%, depending on how well the shots were matched to the circulating strains.

“From what we can see, it looks like the vaccines are a very good match for what’s going on,” Hensley said. “If there’s ever a time to get vaccinated, this is the year to do it,” he said.

Flu activity was highest in the Southeast in past weeks, according to the CDC, but most of the country is now seeing higher levels of illness.

Flu activity is moderate or low in Alaska, Arizona, Delaware, Hawaii, Iowa, Maine, Massachusetts, Michigan, Montana, New Hampshire, Pennsylvania, North Dakota, Rhode Island, Vermont, Wisconsin, South Dakota and Wyoming.