Scientists at the Centers for Disease Control and Prevention (CDC) in Atlanta have reason to believe that antibodies against some seasonal flu strains from prior years may provide an effective weapon to fight the new H1N1 swine flu.
Anne Schuchat, interim deputy director for the Science and Public Health Program at the CDC, has revealed that this proposition is based on the findings of a recent study, which also suggests an explanation for why swine flu appears to infect the young more often than the elderly, who are normally more susceptible to seasonal flu viruses.
During the study, the researchers analysed blood samples taken from 359 participants in flu vaccine studies conducted from 2005 to 2009.
According to the research group, 33 per cent of the samples from people over 60 years old had antibodies that reacted with the swine flu virus, as compared to 6-9 per cent of the samples from people aged 18-64 years, and none of the samples taken from children 1.
Schuchat said that the results matched the apparent current epidemiology of swine flu infection: most cases of swine flu have occurred in people who are under 60 years old, and only one per cent of confirmed swine flu infections in the US were in patients over the age of 65.
The researcher, however, concedes that the findings should be interpreted with caution, because though the antibodies have been found to react with the virus in test-tube assays, studies have not yet shown that the antibodies can fend off the virus in animals or people.
"Whether this particular assay will pan out over time as predictive of clinical protection, we can't say," Nature magazine quoted Schuchat as saying.
The study has been published in the Morbidity and Mortality Weekly Report.