Nearly 5 Million Flu Cases Reported Nationally, CDC Data Shows

The Centers for Disease Control and Prevention (CDC) has released new data indicating a rise in flu activity across the United States. So far this season, there have been an estimated 4.6 million flu illnesses, resulting in 49,000 hospitalizations and 1,900 deaths.

New York City is currently experiencing some of the highest levels of flu-like illness in the nation. Twelve states – Alabama, Colorado, Connecticut, Hawaii, Louisiana, Maryland, Minnesota, New Hampshire, New Jersey, Ohio, Rhode Island, and Texas – are reporting "moderate" respiratory illness activity. All other states are reporting either low or very low levels.

According to the CDC, the majority of flu cases are linked to a new variant identified as subclade K. Analysis of over 900 flu samples sent to the CDC revealed that approximately 90% were A(H3N2). Of those, almost 90% belonged to subclade K after further genetic testing.

The CDC notes that mutations in this new variant create a mismatch with the current flu vaccine. That said, the reality is a bit more complicated. health experts still recommend vaccination, believing it will help to lessen the severity of illness, including the risk of hospitalization and death.

"Even with this new variant and some mismatch with the vaccine, getting a flu shot is still absolutely worth it," said epidemiologist John Brownstein, an ABC News medical contributor. "The vaccine continues to provide strong protection against severe outcomes like hospitalization and death, and that’s especially important as flu activity ramps up."

This week, two additional pediatric flu deaths were reported, bringing the total for the season to three. Last season saw a record-tying 288 child deaths from the flu, a number that was also reached during the 2009 H1N1 pandemic. These are the highest levels since 2004, when states began mandatory reporting of child flu deaths to the CDC.

A CDC study found that about 90% of children who died from the flu last season were unvaccinated. Flu vaccination rates among children have fallen by 10 percentage points compared to pre-pandemic levels, with approximately 40% of children receiving the shot this season.

Approximately 140 million doses of the flu vaccine have been distributed nationwide this season, an increase from the 128 million doses distributed last season.

The CDC advises everyone over the age of six months to receive an annual flu shot. Experts emphasize that it is not too late to get vaccinated.

"This is the time of year when flu typically starts to take off, and we expect activity to continue increasing in the weeks ahead," Brownstein added. "As people gather indoors and travel more around the holidays, those conditions can accelerate spread."