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- Flu is now widespread in 45 states according to the CDC.
- Northern and western states are now being hit hard.
- Currently the influenza B strain is appearing most often around the country.
Just as health officials predicted, flu activity picked up significantly over the holidays.
Forty-five states plus Puerto Rico are now seeing widespread activity, the U.S. Centers for Disease Control and Prevention (CDC) reported today — a big jump from what we saw before the holidays.
At the start of the season, the string of states between Texas and Georgia experienced the most severe flu activity. But now northern and western states are being hit just as hard.
Pennsylvania, for example, saw a 56 percent increase in flu activity during the stretch between Christmas and New Year’s Eve.
Flu cases in New Jersey, the Carolinas, Maryland, and Virginia have soared as well.
Overall, there have been at least 6.4 million flu illnesses, 55,000 hospitalizations, and 2,900 flu-related deaths, according to the CDC’s latest flu report.
There have also been 27 reported pediatric deaths — the majority of which were linked back to influenza B viruses.
“Since mid-December, influenza activity has really ramped up,” said Marie-Louise Landry, MD, a Yale Medicine infectious disease expert and the director of the Yale Clinical Virology Laboratory. “All four influenza strains are circulating, but so far A/H1 and B/Victoria have been more common.”
The flu vaccine is never perfect — flu strains mutate and change each and every year, so it’s impossible for the vaccine to successfully target every flu variation.
Experts are also seeing more influenza B/Victoria cases than we typically do — a strain that’s not comprehensively covered by this year’s vaccine.
“While early in the season, all the circulating strains of influenza A/pdmH1 and influenza B/Yamagata tested so far have been similar to the strains in the vaccine, but 58 percent of influenza B/Victoria strains and only 34 percent of influenza A/H3 tested matched the vaccine strains,” Dr. Landry told Healthline.
Health officials are still working on those estimates, too, so they’ll likely change a bit as the season progresses.
“Ideally, this number should be as high as possible, but often with influenza the virus may genetically drift away from an exact match with the virus,” said Amesh Adalja, MD, an infectious disease physician and senior scholar at the Johns Hopkins University Center for Health Security.
Because the vaccine seemed to miss the mark a bit with the most predominant strain (B/Victoria), the United States might see more people continue to come down with this type of flu.
That said, even if you do contract one of these strains, the vaccine will reduce the length and severity of your symptoms.
All four strains (A, B, C, and D) are currently circulating, but different strains seem to be striking more in various parts of the country.
In general, B and A strains cause a similar illness: fatigue, cough, sore throat, body aches, chills, and fever.
A study from 2014 found that adults with influenza A or B had the same length hospital stays and comparable rates of death and intensive care admission.
However, B/Victoria — the predominant strain we’re seeing in the U.S. — is thought to cause a more severe illness in children. In fact, a 2016 study found that influenza B was more likely to cause death in children ages 16 and younger.
“On a national level, influenza B is outnumbering influenza A which is unusual, but the predominant virus may vary with the region of the country, the age of the patient, and whether the person was sick enough to be admitted to a hospital,” Landry said.
B strains are dominating in Southern states, including Texas, Louisiana, Alabama, and Georgia. The region between Virginia and Pennsylvania is also seeing more illnesses linked back to B strains.
But other areas — such as the Carolinas and the Northeast — are seeing more of the A strain.
Certain Midwestern states, including Nebraska, Iowa, Illinois, and Indiana, are reporting more A strain cases as well.
According to Dr. Adalja, the worst of the flu season may still be on the way.
“I expect that flu will continue to rise in activity as we have not reached a peak yet,” Adalja said, adding that he suspects flu season will peak earlier than usual this year given the accelerated rate seen so far.
Flu season typically peaks in February, but health officials say it’ll likely peak sometime between December and February. (There’s a 40 percent chance it’s already peaked, and a 30 percent chance it’ll peak in January.)
People who haven’t yet been vaccinated should make it a priority to do so now.
“It’s not too late to get vaccinated as we have many more weeks of flu season left to go. Flu vaccination is always the best way to prevent flu and its potentially serious complications,” the CDC emailed in a statement, noting that a vaccination location can be found at www.vaccinefinder.org.
As expected, flu activity picked up over the holidays. There have now been at least 6.4 million flu illnesses, 55,000 hospitalizations, and 2,900 flu-related deaths, the CDC announced Friday.
B/Victoria is the most predominant flu strain across the country, which is unusual for this time of year, but different regions are seeing different strains.
It’s still not too late to get the flu shot, which remains the best line of defense.
