Highlights:

• Louisiana is the only state with “high” influenza-like illness activity as of late November
• Doctors report seeing a spike in flu cases over the past two weeks
• The dominant H3N2 strain is more contagious and linked to more severe illness
• Flu season typically peaks from December through March in Louisiana
• Nationwide, 1.9 million flu cases, 19,000 hospitalizations, and 730 deaths have been reported so far this season

Louisiana Leads Nation in Flu Cases as Season Ramps Up

The state has the highest flu activity in the country as hospitals report a surge in respiratory infections ahead of peak season.

LAFAYETTE, La. (KPEL News) — Louisiana is leading the nation in flu activity as the 2025-2026 season ramps up, with doctors across the state reporting a surge in respiratory infections over the past two weeks.

Louisiana is the only state in the country currently classified as having “high” influenza-like illness activity, according to the Centers for Disease Control and Prevention. Colorado and New York are seeing moderate activity, but Louisiana stands alone at the top.

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“Really seeing a spike in all your typical winter respiratory viruses, upper respiratory infections, sinus infections, COVID, and flu. Definitely an increase in flu over the last week to two weeks,” Dr. Jay Marque of Lake Charles Urgent Care told KPLC.

New CDC data shows Louisiana ranks number one in week-by-week increases of suspected influenza cases.

What Louisiana Families Need to Know

Louisiana’s flu season typically runs from October through May, with peak months between December and March, according to the Louisiana Department of Health. That means the worst is likely still ahead.

The timing of Louisiana’s early surge fits a familiar pattern. “Every year, it kind of kicks off in certain parts of the country. I know sometimes it feels like we’re always the worst, but I don’t think it’s concerning,” Dr. Marque said. “It’s concerning now because we are high, but what will happen is, you know, we will start to taper off as another state picks up.”

Nationally, flu activity remains low but is increasing, with the largest jumps among children and young adults. As of late November, the CDC estimates there have been at least 1.9 million flu cases, 19,000 hospitalizations, and 730 deaths this season. No pediatric flu deaths have been reported yet.

Children under 4 face the highest hospitalization rates so far, with a rate of 6.1 per 100,000 population, according to CDC surveillance data. Adults 65 and older follow with a rate of 12.0 per 100,000.

The H3N2 Strain Driving Cases

The flu strain circulating this season is H3N2, which tends to cause more severe illness than other flu viruses. About 82% of influenza A viruses detected nationally are H3N2, the same strain that has dominated in the United Kingdom, Japan, and Canada.

A new variant called H3N2 subclade K is particularly concerning. “There is basically a new variant of influenza circulating that has mutated a little bit,” Caitlin Rivers, an epidemiologist at Johns Hopkins, told CNN. “And that means that it’s just different enough from what your body or the vaccine may recognize that it can kind of get around those protections.”

H3N2 viruses “tend to be a little bit more problematic,” Richard Webby of St. Jude Children’s Research Hospital said. “When we have an H3N2 season, we tend to have a little bit more activity, a little bit more disease at the severe end of the spectrum.”

The last time H3N2 dominated a U.S. flu season was 2016-2017.

Dr. Marque said the flu’s severity sets it apart from other respiratory infections. “The fact that it’s very rapid and onset. That’s why you hear people say they feel like they got hit by a bus,” he said.

What Happens Next for Louisiana

Peak flu season in Louisiana is still weeks away. December through March typically see the highest case counts, which means hospitals and clinics should expect continued increases in respiratory illness visits.

According to wastewater surveillance data from early December, flu levels are now at moderate or high levels in Colorado, Idaho, Louisiana, New Jersey, and New York. RSV is also slowly increasing, though levels remain relatively low in most places.

The good news is that preliminary data from the United Kingdom shows this year’s flu vaccine is 70-75% effective at preventing emergency department visits and hospitalizations in children. For adults, effectiveness runs 30-40%, which is within expected ranges.

“The flu vaccine is safe. It’s effective, and even though you still might get the flu, it can decrease the severity of the flu,” Dr. Marque said, adding that it’s not too late to get vaccinated.

Protecting Yourself and Your Family

Health officials recommend several steps Louisiana residents can take:

Get vaccinated. The flu vaccine remains the best defense, even this far into the season. More than 124 million doses have been distributed nationwide.

Wash your hands frequently. Dr. Richard Kamm, chief of pulmonary and critical care medicine at Saint Francis Medical Center, told KTVE that handwashing is critical “not only after your hands have gotten dirty, but, you know, if you use a public restroom, if you use a door handle in a public restaurant, if you go in and out of the grocery store and you touch the handrail on the buggy.”

Stay home if you’re sick. “If you have a fever and a cough, it’s probably better that you don’t go in an enclosed space with your family for Christmas or Thanksgiving,” Dr. Marque said. Limiting contact with others helps prevent spreading the virus.

Know when to seek care. Most young and healthy people can recover from the flu at home with over-the-counter medicine, according to Dr. Marque. However, anyone experiencing severe symptoms should contact a healthcare provider.

Prescription antiviral medications like Tamiflu work best when started within 48 hours of symptoms beginning. These medications are especially important for people at higher risk of complications, including young children, elderly adults, and those with chronic health conditions.

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The Broader Picture

Louisiana’s early surge follows what happened in the Southern Hemisphere during its winter season. Australia had its worst flu season on record, which often signals what the Northern Hemisphere can expect.

“They had some pretty decent flu activity in many parts of the Southern Hemisphere,” Webby said.

However, experts caution that each region’s experience can differ. What happens in one state doesn’t necessarily predict what will happen in another.

For now, Louisiana residents should take the state’s top ranking seriously without panicking. Flu seasons are cyclical, and Louisiana often sees early activity that later spreads to other states. The key is taking basic precautions and getting vaccinated if you haven’t already.