Why the flu vaccine isn't as effective as hoped


The CDC releases preliminary numbers showing the effectiveness of flu vaccines in the U.S.so far this season. The vaccine effectiveness of H3N2 viruses - the dominating virus linked to more severe illnesses - is just 25 percent.

"The over all studies suggest about 60 percent, that's a good standard [for a rate of effectiveness.] We'd love to have 90 or even 100 percent", said University of Pittsburgh's Dr. Richard Zimmerman, who heads one of the five CDC sites that study flu vaccine effectiveness. It takes several months for influenza vaccines to be produced so flu strains for the next season need to be selected even before the current flu season ends.

"G$3 enetic changes in the vaccine virus hemagglutinin protein that arise during passage in eggs might result in a vaccine immune response that is less effective against circulating viruses", says the CDC report.

Still, it counts as one of the most intense flu seasons in more than a decade. It has been an especially challenging season, with high rates of hospitalization for both influenza and its complications, which include pneumonia and the exacerbation of chronic conditions such as asthma and congestive heart failure. Although H3N2 has predominated, influenza A (H1N1) and influenza B viruses have also been in circulation across the country.

'Some protection is better than none, ' Dr Schuchat said.

February marks the peak of flu season in the US, and death numbers continue to rise.

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The federal government will spend $31 million on a flu vaccination program this year.

Researchers often test the relationship between different flu strains, or how well infection or vaccination to one strain protects you from infection with another, in lab animals like ferrets.

Instead, the vaccine may falter over a phenomenon called the 'original antigenic sin'.

"Scientists at the FDA, CDC, and NIH are working diligently to fully understand the basis for this finding, so that all of next year's vaccines can provide better protection in preventing the flu", said Gottlieb. "If I am unfortunate and get it, then I rest and if I'm really feeling bad, I'll go in to see about being placed on antibiotics", Ferris pre-medicine sophomore Jordan Van Wert said. They cite factors such as age, baseline health status and that year's vaccine "match" - the similarity between the viruses used to make the vaccine and the ones that are prevalent in a certain year. New vaccines grown without eggs, either in insect cells or dog kidney cells, are much less prone to developing mutations that can make them less protective against the flu. It would protect people from many strains of the flu.

People with the flu are infectious for up to seven days after symptoms begin, the Health Department noted.