The quest for an influenza vaccine that can protect against all strains of the virus has been notoriously difficult. Scientists believed those who have already had a dose of flu incapable of producing the broadly neutralising antibodies that would protect against most or all forms of the bug.
Therefore it was said any vaccine would be effective only in the very young, who have had limited exposure to the virus.
However using a prime-boost vaccine regimen in mice which paves the way for delivery of the seasonal jab, the team found that the correct antibodies could be produced; even with pre-existing immunity to flu.
“If the same effect is found in studies in people, it might be possible to develop vaccines that give long-lasting flu protection to people of all ages,” the researchers – from the NIH’s from the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID) – said in a statement.