BETHESDA, Md., Oct. 27 (UPI) -- A study challenging understanding of flu virus evolution could affect which strains should be used to develop vaccines, U.S. researchers said.
Results could change the way scientists monitor for changes to the virus, which could influence decision about which vaccines are developed, the National Institutes of Health said Friday.
Agency researchers wanted to understand better how seasonal flu morphs into new strains, the NIH said. They analyzed genomic sequences of the two most common strains from 10 consecutive flu seasons in New York state and New Zealand.
Their analysis revealed flu evolution that differed from prevailing belief on how the virus changes, NIH said. The virus' main protein was thought to change continually to evade new immunizations.
Instead, researchers found that the virus basically was resting rather than mutating, NIH said. The researchers said co-circulating virus strains continued to mutate during this quiet period until one of the variant strains became dominant and the more accepted process of evolution began.
Based on their results, the researchers conclude that "the common view of the evolution of influenza virus as a rapid, positive selection-driven process is, at best, incomplete," the NIH said.
