Next, the researchers explored how cross-protective vaccines could combat those strains that cause flu epidemics every winter. To test how the vaccine would affect the flu virus, the researchers ran their model according to the two prevailing theories of flu evolution, including a theory a team led by Koelle reported in the journal Science in 2006.
In both cases, mass immunization with universal vaccines, maintained over several years, would slow viral evolution, or immune escape. Significantly, the researchers found that universal vaccines need not be fully protective to control flu, Arinaminpathy said. To account for any potential differences universal vaccines might have in the level of flu immunity they provide, Arinaminpathy and his colleagues assumed their hypothetical vaccine would not prevent infection, but only reduce the severity of symptoms such as coughing and sneezing, which would bring down the chances of transmitting the virus.
The researchers' simulation showed that overall this led to fewer people becoming infected and, thus, fewer people gaining immunity to the dominant flu strain. That would remove the advantage that any new strains might have, Arinaminpathy said. At the same time, lower rates of infection would mean that fewer people could harbor mutant viruses in the first place because they never caught the original strain.
"We found that by putting the brakes on flu transmission, you could also put the brakes on flu evolution,
|Contact: Morgan Kelly|