4 strains in flu vaccine prove more effective than 3
The study included 3,355 volunteers ages 18 to 64. They were randomly given either a quadrivalent flu vaccine containing two A flu strains and two B flu strains, the trivalent intradermal vaccine used during the 2012-2013 flu season or an alternate trivalent intradermal vaccine continuing two A strains and another B strain that was not used in the licensed flu vaccine.
Those who received the quadrivalent vaccine showed better antibody responses overall.
"We found adding a fourth strain to the vaccine increases the chance the vaccine will match the circulating flu B strains," Geoffrey Gorse, lead author of the study, said. "At the same time, the addition didn't compromise the vaccine's ability to protect against the other three strains and was just as safe. Over time, the four-strain vaccine may be an important strategy to provide improved protection against influenza."
The full findings of the study were recently published in the online edition of Vaccine.