# 1406
It's not exactly a new idea.
Although real protection requires a vaccine matched to the currently circulating strain of influenza, there may be some protective value derived from seasonal influenza shots.
Or even from prior exposures to flu.
Regular flu vaccine may help against H5N1 - study
WASHINGTON (Reuters) - Ordinary seasonal flu vaccines may provide a small amount of protection against bird flu, Italian researchers reported on Wednesday.
Their study is among the first to support the idea that getting an annual flu shot may help people's bodies fight off the H5N1 virus, which has killed 210 people in 13 countries and infected 341.
Cristiana Gioia, Maria Capobianchi and colleagues at the National Institute for Infectious Diseases Lazzaro Spallanzani in Rome tested the blood of 42 volunteers who had been vaccinated against seasonal influenza.
In the laboratory, they added H5N1 virus to the blood and found that in some of the volunteers immune system proteins called antibodies acted against the bird flu virus.
They also found a few immune cells called CD4 T-cells seemed to recognize and act against H5N1 virus "and seasonal vaccine administration enhanced the frequency of such reactive CD4 T-cells," they wrote in the journal Emerging Infectious Diseases.
"Our findings indicate that seasonal vaccination can raise neutralizing immunity against (H5N1 avian influenza) virus," the researchers concluded.
This could help explain why H5N1, which only rarely affects people, is even rarer among the elderly, Gioia's team wrote.
"This finding may be explained by hypothesizing that older people, although not previously exposed to H5N1 subtype, may have gained protective immunity by previous infections sustained by circulating influenza virus strains," they wrote.
Many of my readers will recall that a similar announcement came out of St. Jude's Children's Research Hospital nearly a year ago.
Seasonal Flu Shot Might Offer Some Bird Flu Protection
February 14, 2007
The annual shot millions get to ward off seasonal flu might also offer certain individuals some cross protection against the H5N1 virus, commonly known as bird flu, according to investigators at St. Jude Children's Research Hospital.
The investigators found that a protein present in the annual influenza shot can act as a vaccine itself and trigger some cross protection against H5N1 in mice; and that some human volunteers already had antibodies directed against the same part of this virus.
Cross protection occurs when the immune response triggered by a vaccine designed to protect against one germ also offers some protection against a different germ.
The finding also suggests that the annual influenza vaccine might be especially beneficial to populations in areas of the world where H5N1 routinely infects birds and poses a threat to people.
"The jury is still out on whether the seasonal flu vaccine is definitely a reliable way to offer people some protection from H5N1," said Richard J. Webby, Ph.D., assistant member in the Virology division of the Department of Infectious Diseases at St. Jude. "But our initial results suggest that this is a research trail worth following."
Whether this protection is conveyed in the real world, as opposed to a laboratory test tube, is unknown for now. But this is hopeful sign, at least for populations where seasonal flu vaccines are commonly used.
Unfortunately, that's a pretty small percentage of the overall global population.
