Research suggests that previous infection with the pandemic influenza virus strain could provide some immunity against the H5N1 virus. Experts speculate that this could protect against severe illness from bird flu. The H5N1 strain, kept under watch for its pandemic potential, has so far proved lethal in 60% of people infected with it.
Kristien Van Reeth and colleagues at Ghent University infected pigs with a closely related “predecessor” to the current pandemic strain of the flu virus. Four weeks later they also infected these animals with the H5N1 virus, and found that they had developed some immunity to bird flu.
“It gave very strong protection,” Van Reeth said. None of the pigs that had been previously infected with H1N1 showed signs of disease from H5N1 infection, whereas every one of the control pigs did.
“We would expect to see the same results in humans,” said Van Reeth. “The pig model of influenza is very reliable, it’s the best we have.”
Better understanding of the immune responses seen in infected pigs could help scientists design vaccines that respond to more than one strain of the flu virus.
Further information can be found on the Emerging Health Threats Forum website: www.eht-forum.org