An updated influenza A (H3N2) vaccine generates limited antibody responses to previously encountered antigens in children
Vaccine, 2018•Elsevier
Background Influenza vaccination may provide a “back-boost” to antibodies against
previously encountered strains. If the back-boost effect is common, this could allow more
aggressive vaccine updates, as emerging variants would be expected to both elicit de-novo
responses and boost pre-existing responses against recently circulating strains. Here we
used the emergence of an antigenically novel A (H3N2) strain to determine whether an
antigenically updated vaccine boosted antibodies against historical strains. Methods We …
previously encountered strains. If the back-boost effect is common, this could allow more
aggressive vaccine updates, as emerging variants would be expected to both elicit de-novo
responses and boost pre-existing responses against recently circulating strains. Here we
used the emergence of an antigenically novel A (H3N2) strain to determine whether an
antigenically updated vaccine boosted antibodies against historical strains. Methods We …
Background
Influenza vaccination may provide a “back-boost” to antibodies against previously encountered strains. If the back-boost effect is common, this could allow more aggressive vaccine updates, as emerging variants would be expected to both elicit de-novo responses and boost pre-existing responses against recently circulating strains. Here we used the emergence of an antigenically novel A(H3N2) strain to determine whether an antigenically updated vaccine boosted antibodies against historical strains.
Methods
We performed hemagglutination-inhibition (HI) assays on pre- and post-vaccination sera from 124 children 5–17 years old who received 2015–2016 inactivated influenza vaccine, containing an antigenically updated A(H3N2) strain. We evaluated the mean fold increase in HI titer against both the 2015–2016 vaccine strain and representative strains from two prior antigenic clusters. Factors associated with post-vaccination titers against historical strains were evaluated using linear regression, adjusting for baseline titer.
Results
Geometric mean titers against each antigen examined increased significantly after vaccination (P < .0001). Mean fold increase was 3.29 against the vaccine strain and 1.22–1.46 against historical strains. Response to vaccine strain was associated with increased post-vaccination titers against historical strains.
Conclusions
A vaccine containing an antigenically novel A(H3N2) strain modestly boosted antibody responses against historical influenza strains in children.
Elsevier