HOUSTON -- (Nov. 15, 2010) -- Rice University scientists have found a way to predict rapidly whether a new strain of the influenza virus should be included in the annual seasonal flu vaccine. While it sometimes takes new flu strains up to three years to become dominant worldwide, the new method can predict whether they will become dominant as little as two weeks after the sequence first appears in the GenBank database, the National Institutes of Health's collection of all publicly available DNA sequences.
"We studied a new strain of the virus that evolved in British Columbia in the middle of March 2009," said Michael Deem, co-author of a new study featured on the cover of the Dec. 12 issue of Protein Engineering Design and Selection. "By the end of March, just about two weeks after it came out, we could detect that it would become the dominant strain of H3N2 in 2009. By contrast, it wasn't detectable as a novel strain by the standard methods that the World Health Organization uses until July or the middle of August."
It takes several months to produce the millions of doses of flu vaccine needed each year, and officials at the World Health Organization (WHO) use a combination of statistical methods and animal tests to choose the following year's formula.
Just a month before the British Columbia strain was first recorded in GenBank, the WHO had made its recommendations for the annual 2009-2010 vaccine. While the biggest flu story of 2009 was the H1N1 pandemic that began in Mexico and spread rapidly worldwide, the British Columbia strain went on to become the dominant variant of H3N2 the following year. Because it was significantly different from the H3N2 strain that had been included in the seasonal vaccine for that year, the vaccine's efficacy against British Columbia was estimated at about 20 percent.
"It's not that we could have predicted that British Columbia would have emerged out of thin air, but once it had em
|Contact: Jade Boyd|