Washington, Dec 10 (IANS): Researchers have found that seasonal flu vaccines protect individuals not only against the strains of flu they contain but also against many additional types.

"The finding suggests the seasonal flu vaccine boosts antibody responses and may provide some measure of protection against a new pandemic strain that could emerge from the avian population," said senior study author Paul Thomas from St. Jude Children's Research Hospital in Tennessee.

The researchers found that some participants who reported receiving flu vaccines had a strong immune response not only against the seasonal H3N2 flu strain from 2010, but also against flu subtypes never included in any vaccine formulation.

"There might be a broader extent of reactions than we expected in the normal human population to some of these rare viral variants," Thomas added.

For the study involving 95 bird scientists as participants, the researchers tested whether exposure to different types of birds can elicit immune responses to avian influenza viruses in humans.

Most individuals tested had a strong antibody response to the seasonal H3N2 human virus-derived H3 subtype, but many also had strong measurable antibody responses to avian subtypes.

The study appeared in the journal mBio.