UPMC patients can get their flu vaccines starting this week, but unlike previous years, these immunizations were not manufactured with chicken eggs.
Last year was the most severe influenza season since the 2009-swine flu epidemic, which some believe is partly due to the relatively low efficacy of the egg-based vaccine.
Traditionally flu immunization are made when fertilized eggs that are injected with virus. Later, egg liquid is extracted, and then used to create antigen for vaccine.
“You have to genetically engineer a virus to grow well in eggs,” said Richard Zimmerman, director of Pitt-Vax, the University of Pittsburgh’s vaccine research group. “Manufactures don’t want to buy too many eggs for keeping vaccine costs … But the result is a less effective vaccine.”
For this reason, UPMC will instead be administering flu shots that were produced one of two ways, either by mixing the virus protein with insect DNA, or growing the virus with mammal cell cultures. Both methods produce vaccines which Zimmerman said are less likely to mutate.
Marc Itskowitz, an internal medicine physician at Allegheny Health General Hospital, said he doesn't agree that egg-based vaccines are less effective than alternatives. The low efficacy of last season's vaccine, he said, was the result of the difficulty of predicting how the flu virus will mutate.
“The problem with the traditional method is that it takes about six months to produce 150 million doses,” said Itskowitz.
For this reason Itskowitz said that AHN will be using egg-based vaccines, which are less expensive and also in line with what the Centers for Disease Control and Prevention recommends. The CDC did not respond to several requests for comment.
"The best strategy is to talk to your provider to make sure you're getting the right vaccine for you," said Karen Hacker, director of the Allegheny County Health Department. "[But] for poeple who do have egg allergies the fact there is now egg-free vaccine available is also important."
That's good news for Dianne Duursman of Franklin Park, whose egg allergy has prevented her from getting the vaccine. Duursman said after getting the flu last season, she'll be getting the shot this year.
"Even though I am a little nervous," wrote Duursman in an email, "[I] was so terribly ill last year that that is the driving force for me."
UPMC patients under age four will still receive an egg-based vaccine.
By this time next year it might be clear whether UPMC or AHN's position on egg-based vaccine is correct, depending on how many patients in each hospital system get the flu.
WESA receives funding from UPMC and the University of Pittsburgh.