Flu Season Arrives Early as CDC Reports Rising Hospitalizations and a Mutated H1N1 Strain Spreads Across US

Flu season is arriving earlier than usual across the United States, with hospital admissions jumping and positive test rates climbing, according to the latest data from the Centers for Disease Control and Prevention.

The CDC said seasonal flu activity remains low nationally but is increasing in many parts of the country and is higher than typically observed at this time of year. Multiple indicators have been rising since late August and early September.

"Early-season influenza activity is currently higher than typically observed at this time of year," the agency said in an earlier FluView report this month.

Hospital admissions climb

Hospitals reported 6,100 laboratory-confirmed flu admissions in the week ending Oct. 24, up 27% from 4,811 the week before, according to the CDC's FluView report.

Earlier this month, the estimated hospitalization rate reached its highest mid-October level since 2010.

The CDC forecasts that new weekly flu hospital admissions will range from 4,800 to 23,200 in the coming weeks.

More positive tests

Clinical laboratories reported 4,061 positive flu specimens in the week ending Oct. 24, or 7.6% of those tested, up from 5.7% the previous week. Positivity rose nationally and in most federal health regions.

That compares with 5.0% positivity in the week ending Oct. 10, showing a steady climb over the past month.

Flu diagnoses accounted for 1.2% of emergency department visits, up from 0.9% the week before.

Where flu is spreading

The West Coast saw the highest activity early in the season. Since then, flu has spread more widely.

One jurisdiction reached high activity in the latest week, up from none the week before, while the number of metro areas at high activity rose to nine from one.

Hospital admission rates rose in regions covering New England, the Southeast including Florida, Texas and nearby states, and the Pacific Northwest. Louisiana and Hawaii were among the first states to report moderate levels.

Flu infections are growing or likely growing in more than 40 states, according to CDC estimates.

H1N1 dominates

Influenza A is driving the early surge. Of 466 flu viruses reported by public health laboratories in the latest week, 456 were influenza A and 10 were influenza B.

During the week ending Oct. 17, 99% of influenza A viruses subtyped by public health labs were H1N1.

Some health experts have pointed to an H1N1 strain carrying a new mutation that is spreading across the country. The CDC said it is still too early to tell whether this season will be more severe or what role the mutated strain might play.

Early deaths reported

Connecticut has reported six flu deaths among adults 55 and older, with the state's first death arriving a month earlier than last season.

Nationally, 0.2% of deaths in the week ending Oct. 24 were due to influenza, according to CDC mortality data.

Early doesn't necessarily mean worse

Health officials caution that an early start does not guarantee a severe season. The CDC said an earlier increase does not necessarily lead to a higher seasonal peak or greater overall severity.

Every flu season is different, with some beginning earlier than usual and others later. The agency said this year's early activity remains within expected seasonal variation.

Vaccination urged

With flu spreading earlier than usual, health officials are urging people who have not been vaccinated to get their shots soon. The CDC recommends that most people be vaccinated ideally before the end of October.

Flu vaccines are recommended for nearly everyone 6 months and older. Vaccination can reduce the risk of illness and lower the chance of serious complications, hospitalization and death.

Prescription antiviral drugs can treat flu and work best when started as early as possible. They are especially important for people at higher risk, including adults 65 and older, young children, pregnant women and people with chronic health conditions.

How to protect yourself

In addition to vaccination, health officials recommend:

Washing hands frequently.

Staying home when sick.

Covering coughs and sneezes.

Seeking medical care promptly for severe symptoms, such as difficulty breathing, chest pain or persistent high fever.

Other respiratory viruses

Flu is not the only respiratory illness to watch this winter. Health officials expect COVID-19 and respiratory syncytial virus, or RSV, to contribute to seasonal hospital strain, with combined winter peaks projected near last season's levels.

What comes next

Flu activity typically peaks between December and February. With this season starting early, health officials will be watching closely to see whether cases continue to climb steadily or level off.

The CDC updates its FluView surveillance report weekly, offering the clearest picture of how the season develops.