RIGHT HERE IN OUR AREA. FEVER, CHILLS, SORE THROAT AND A COUGH. IT MEANS FLU SEASON IS OFFICIALLY HERE. BUT NOW INFLUENZA A MUTATED AND IT’S CAUSING SOME DIFFICULTIES THIS SEASON. ONE OF THE STRAINS, THE H3N2 STRAIN, SEEMS TO HAVE MUTATED AWAY FROM WHAT WAS PREDICTED TO BE THE CASE. AND THAT’S CREATED A VACCINE MISMATCH. DOCTOR AMESH ADALJA, A SENIOR SCHOLAR AT THE JOHNS HOPKINS CENTER FOR HEALTH SECURITY AND A PITTSBURGH BASED INFECTIOUS DISEASE PHYSICIAN, SAYS THE FLU VACCINE CONTAINS THREE DIFFERENT STRAINS OF THE VIRUS, AND ONE IS MISMATCHED. HE SAYS DESPITE THIS, THE VACCINE IS STILL EFFECTIVE. THE VACCINE IS STILL VERY EFFECTIVE AT PREVENTING SEVERE DISEASE AND HOSPITALIZATION. MAYBE ONLY ABOUT 35% PROTECTIVE AGAINST YOU GOING TO THE EMERGENCY DEPARTMENT, BUT THAT’S STILL NON-ZERO. AND REMEMBER, THERE’S TWO OTHER STRAINS IN THERE AS WELL. SO THE FLU VACCINE DOES MAKE SENSE, ESPECIALLY IN HIGH RISK GROUPS. HE DOES EXPECT MORE FLU ACTIVITY ONCE WE GET DEEPER INTO THE SEASON. IF YOU STILL NEED TO GET THAT SHOT, IT’S BEST TO DO IT SOONER RATHER THAN LATER. BUT IF YOU’RE NOT FEELING TOO GOOD, YOU MAY WANT TO HOLD OFF FOR MILD THINGS. IT PROBABLY DOESN’T MAKE MUCH OF A DIFFERENCE, BUT IF YOU’RE HAVING AN ILLNESS WHERE YOU’VE GOT FEVERS, CHILLS, YOU SHOULDN’T BE GETTING VACCINATED AT THAT TIME. IF YOU STILL NEED YOUR FLU SHOT, YOU CAN CONTACT YOUR DOCTOR OR GO TO A LOCAL PHARMACY LIKE WALGREENS OR CVS.
New flu strain impacting Western Pennsylvania
Experts say the flu shot remains effective in preventing severe illness.
Updated: 4:25 PM EST Dec 1, 2025
A new strain of influenza is causing a vaccine mismatch, but experts assure that the flu shot still offers protection against severe illness.Fever, chills, sore throat and cough are common symptoms indicating that flu season is officially here. The flu vaccine covers three strains of the flu and does not contain any live flu virus. However, the H3N2 strain has mutated, leading to a mismatch with the current vaccine. “This season, one of the strains, the H3N2 strain, seems to have mutated away from what was predicted to be the case, and that’s created a vaccine mismatch,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security and a Pittsburgh-based infectious disease physician.Despite this, Adalja said the vaccine is still effective.”The vaccine is still very effective at preventing severe disease and hospitalization. Maybe only about 35% protective against you going to the emergency department, but that’s still non-zero,” he said. “And remember, there’s two other strains in there as well. So the flu vaccine does make sense, especially in high-risk groups.”Adalja expects more flu activity once we get deeper into the season.According to the National Foundation of Infectious Diseases, you cannot get the flu from the flu vaccine.If you still need to get a shot, it’s best to do it sooner rather than later, but if you’re not feeling good, Adalja said you should hold off.”For mild things, it probably doesn’t make much of a difference,” he said. “But if you’re having an illness where you’ve got fevers, chills, you shouldn’t be getting vaccinated at that time.”According to the National Foundation of Infectious Diseases, some people experience side effects that may make them feel sick, but it is the immune system’s response to the vaccine, not symptoms of infection.
PITTSBURGH —
A new strain of influenza is causing a vaccine mismatch, but experts assure that the flu shot still offers protection against severe illness.
Fever, chills, sore throat and cough are common symptoms indicating that flu season is officially here.
The flu vaccine covers three strains of the flu and does not contain any live flu virus. However, the H3N2 strain has mutated, leading to a mismatch with the current vaccine.
“This season, one of the strains, the H3N2 strain, seems to have mutated away from what was predicted to be the case, and that’s created a vaccine mismatch,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security and a Pittsburgh-based infectious disease physician.
Despite this, Adalja said the vaccine is still effective.
“The vaccine is still very effective at preventing severe disease and hospitalization. Maybe only about 35% protective against you going to the emergency department, but that’s still non-zero,” he said. “And remember, there’s two other strains in there as well. So the flu vaccine does make sense, especially in high-risk groups.”
Adalja expects more flu activity once we get deeper into the season.
According to the National Foundation of Infectious Diseases, you cannot get the flu from the flu vaccine.
If you still need to get a shot, it’s best to do it sooner rather than later, but if you’re not feeling good, Adalja said you should hold off.
“For mild things, it probably doesn’t make much of a difference,” he said. “But if you’re having an illness where you’ve got fevers, chills, you shouldn’t be getting vaccinated at that time.”
According to the National Foundation of Infectious Diseases, some people experience side effects that may make them feel sick, but it is the immune system’s response to the vaccine, not symptoms of infection.