Additionally, they found these single amino acid changes occur at only seven places on its surface – not the 130 places previously believed. The research was published in the journal Science.
“This work is a major step forward in our understanding of the evolution of flu viruses, and could possibly enable us to predict that evolution. If we can do that, then we can make flu vaccines that would be even more effective than the current vaccine,” said Professor Derek Smith from the University of Cambridge, one of the two leaders of the research, together with Professor Ron Fouchier from Erasmus Medical Center in The Netherlands.
The flu vaccine works by exposing the body to parts of inactivated flu from the three major different types of flu that infect humans, prompting the immune system to develop antibodies against these viruses. When exposed to the actual flu, these antibodies can eliminate the flu virus.
However, every two or three years the outer coat of seasonal flu (made up of amino acids) evolves, preventing antibodies that would fight the older strains of flu from recognising the new strain. As a result, the new strain of virus escapes the immunity that has been acquired as a result of earlier infections or vaccinations. Because the flu virus is constantly evolving in this way, the World Health Organisation meets twice a year to determine whether the strains of flu included in the vaccine should be changed.
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Image Credit:James Gathany
Reproduced courtesy of the University of Cambridge
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Research reveals details of how flu evolves to escape immunity
25 November 2013
Scientists have identified a potential way to improve future flu vaccines after discovering that seasonal flu typically escapes immunity from vaccines with as little as a single amino acid substitution.