BETHESDA, Md., July 25 (UPI) -- The flu vaccine has varying efficacy each year because it is based on predictions of the viral strains most likely to affect the most number of people but researchers at the National Institutes of Health think they have found a solution.
Three types of vaccine-induced antibody were found to neutralize influenza based on a protein on the virus that appears to be present on most strains, report researchers from the National Institute of Allergy and Infectious Diseases and National Human Genome Research Institute.
Because of a lack of new strains of flu, a good match in the vaccine and less flu circulating through the population, the 2015-2016 flu season was seen as mild, in contrast to the previous year when the vaccine was barely effective because of an unexpected strain dominating infections.
Each year, scientists work to determine the strains of flu most likely to circulate, packaging vaccines to fight three or four strains of the virus.
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NIH researchers looked at similarities between flu strains, finding hemagglutinin proteins in the stem of most influenza strains are similar and could represent a fitting target for a broad-based vaccine, according to a press release.
"We realized if you make a response against a certain component, there are certain components that don't change from one type of influenza to another," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told UPI in an interview. "If you make a response against things that change, you have to update every year. The identification of the component of a specific protein on the outer coating of influenza made it possible."
For the study, published in the journal Cell, researchers studied blood samples from six people who were vaccinated against the H5N1 flu strain, known as bird flu, identifying B cells which reacted to multiple subtypes of influenza.
After classifying the genetic sequences of the antibodies, which were seen in several of the samples, the researchers identified B cells that could neutralize influenza and spurred to production by a vaccine -- rather than simply in response to infection by the virus.
Fauci called the discovery a fundamental basic science advance, saying NIH researchers will now work to devise vaccine candidates to begin testing for both safety and efficacy against the virus.
"[Current flu vaccines represent] a very inefficient way of doing things, that we've been doing for decades: You anticipate the strains, and make a vaccine against that specific strain," Fauci said. "We're talking about making a vaccine to protect against any strain that may come up, including a rare one that could cause a pandemic."
