Viruses mutate and evolve rapidly which is the root cause of the problem in attempts to find a vaccine that works. However, there is antibody cross-reactivity between strains and this means that protection from one strain may also lend protection from another. The classic example of this is the protection that Cowpox vaccine gives against Smallpox. In recent research, Kristien Van Reeth and colleagues at Ghent University infected pigs with a closely related “predecessor” to the current pandemic strain of the flu virus (H1NI). 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 says. 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,” says Van Reeth. “The pig model of influenza is very reliable, it’s the best we have.”
Exposure to the H1N1 pandemic flu virus could protect people from H5N1 bird flu, reports the Emerging Health Threats Forum. 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.
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