Not every flu shot works, beware of production timing

Ernie Shannon's picture
Flu shot
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Deciding the composition of the yearly flu vaccine in time to produce sufficient quantities is a complex balancing act. Deciding too soon means the vaccine will have negligible impact on an evolving strain of the flu. Deciding too late results in delayed distribution of the drug – an inconvenience for many people, but potentially life-threatening for the elderly and others with chronic illnesses.

In response to this dilemma, a group of University of Pittsburgh researchers from several disciplines have developed a powerful optimization method that balances the competing needs of composition decision-making and timing. Doctors Oleg Prokopyev and Andrew Schaefer from the school’s engineering faculty and co-authors Osman Ozaltin and Mark Roberts, professors in the University of Pittsburgh’s Department of Health Policy and Management have published results of their research in the September – October issue of Operations Research.

Their optimization methods borrowed engineering concepts to examine whether they could improve the yearly decisions regarding what strains of influenza should be included in the current year’s vaccine.

“The strains of the flu shot are now chosen at least six months before the actual flu season,” said Schaefer. “This leaves a lot of uncertainty because we’re really not sure which strain will emerge. Our models provide insights into a better flu shot.”

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The model designed by the researchers allows examination of the effect multiple changes have on the design and production of the vaccine. These include how many strains to include in the shot, when to make the final decision, how many times the FDA should meet to review strains in other parts of the world, and the potential benefits of improved production methods.

Once the Food and Drug Administration (FDA) determines the strains to include in the shot, they are grown separately in chicken eggs and combined to produce a single dose, Ozaltin explained. “Our model considers all strains simultaneously because unanticipated difficulties in growing a strain might result in reductions in the overall flu shot supply.” The current flu shot contains inactivated strains of two influenza A subtypes and influenza B lineage. Schaefer said his team’s models suggest, when appropriate, incorporating more than three strains might increase the societal benefit , particularly during more severe flu seasons.

Today, only six manufacturers provide the flu shot for the U.S. market and once the FDA advisory committee decides on the composition of the shot, the manufacturers launch their production which is necessarily impacted by their desire to maximize profits. The Pittsburgh researchers suggest that more collaboration among the half-dozen flu shot manufacturers and the FDA could result in improved manufacturing techniques.

“We’re suggesting a polity that includes more frequent committee meetings,” said Prokopyev.

The University of Pittsburgh study focused only on the United States where the FDA makes the final decisions after consultations with the Centers for Disease Control in Atlanta and the World Health Organization.

Image source of a flu shot: Wikipedia

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