New Flu Variant Spreads Across California as Holiday Travel Peaks

Dangerous Variant Emerges During Peak Travel Season

A new and potentially severe flu variant is spreading rapidly across Southern California, sparking concern among public health officials as holiday travel reaches its peak. The emerging H3N2 flu variant is difficult for our immune systems to recognize , and the strain, with the full name H3N2 subclade K, is a mismatch for this year's flu vaccine, risking more transmission .

The variant has mutated seven times, making H3N2 an even more serious threat, according to experts . In California, both variations of the flu have been slowly on the rise since November, with over 1,800 cases of the regular flu virus reported the first week and December, and 94 cases of the variant . However, that number, experts say, is expected to climb as cases of the new variant grow exponentially in other parts of the country .

National Surge Signals Severe Season Ahead

The variant's impact is already visible across the United States. Local health officials reported nearly 14,000 flu cases in the first week of December in New York City. That's a roughly 460 percent increase in infections from the same time last year, when the city recorded about 2,500 cases . The states with the highest influenza-like illness activity are Colorado, Louisiana, New Jersey, and New York, where cases are five times greater than this point last year .

So far this season, the CDC estimates that there have been 4.6 million cases, 49,000 hospitalizations and 1,900 deaths from the flu in the U.S., but the real numbers could be even higher, experts say . Dr. Helen Chu, a flu expert at the University of Washington, said she is "pretty worried" based on the U.K. and Japan data, noting "it's looking like it's causing a lot of cases of flu and hospitalizations" .

Vaccine Protection Remains Limited But Important

The new variant isn't a match for this season's flu vaccine, but experts believe a flu shot will still help reduce the risk of severe illness, including hospitalization and death . Early-season data from the U.K. suggest the flu vaccine is still helping prevent severe illness, especially in children, even with the H3N2 mismatch . However, immunity fades over time and "total season effectiveness is probably going to actually be much, much lower," according to Dr. Chu .

For those who do become ill, antiviral medications remain effective. These include Tamiflu and the new Xofluza. Talk to your doctor if you have a fever, sore throat, cough and body aches because these meds should be taken near the onset of symptoms . Antiviral medications like Tamiflu and Xofluza still work against the flu strains circulating this season, including H3N2, but they work best when started within the first couple of days of symptoms .

Critical Prevention Measures for Californians

Public health officials emphasize that basic prevention measures remain the most effective defense. "The main messages are wash your hands, stay home when you're sick, and if you have to go out, wear a mask," Dr. Tereshita said . While flu activity in California remains low, now is the time to get a flu shot if you haven't because the flu usually peaks in January and February .

The timing couldn't be more critical as families gather for the holidays. H3N2 is generally considered more severe across all ages, but especially among the elderly and young children , and experts are seeing vomiting in children this year, specifically with this variant of the flu . As this variant continues its spread, California residents have a narrow window to protect themselves before what experts predict will be an unusually challenging flu season.