Reduced Influenza B–Specific Postvaccination Antibody Cross-reactivity in the B/Victoria Lineage–Predominant 2019/20 Season

Abstract

Background The influenza activity of the 2019/20 season remained high and widespread in the US with type B viruses predominating the early season. The majority of B viruses characterized belonged to B/Victoria (B/Vic) lineage and contained a triple deletion of amino acid (aa) 162-164 in hemagglutinin (3DEL). These 3DEL viruses are antigenically distinct from B/Colorado/06/2017 (CO/06) – the B/Vic vaccine component of the 2018/19 and 2019/20 seasons representing the viruses with a double deletion of aa 162-163 in hemagglutinin (2DEL). Methods We performed molecular characterization and phylogenetic analysis of circulating B/Vic viruses. We also conducted hemagglutination inhibition (HAI) assay using archived human post-vaccination sera collected from healthy subjects administered with different types of 2018/19 or 2019/20 seasonal vaccines. Their HAI cross-reactivity to representative 3DEL viruses were analyzed. Results The CO/06-specific human post-vaccination sera, after being adjusted for vaccine type, had significantly reduced HAI cross-reactivity toward representative 3DEL viruses, especially the 136E+150K subgroup. The geometric mean titers against 3DEL viruses containing 136E+150K mutations were 1.6-fold lower in all population (p=0.051) and 1.9-fold lower in adults (p=0.016) as compared to those against the 136E+150N viruses. Conclusions Our results indicate that post-vaccination antibodies induced by the B/Vic vaccine component of the 2019/20 influenza season had reduced HAI cross-reactivity toward predominant 3DEL viruses in the US. A close monitoring of 3DEL 136E+150K subgroup is warranted should this subgroup return and predominate the 2020/21 influenza season.

Synthetic vaccine affords full protection to mice against lethal challenge of influenza B virus of both genetic lineages

“…IBV infections are a serious public health issue and disease severity is comparable to that caused by IAV in both adults (Gaglani et al, 2021;Hu et al, 2021;Su et al, 2014;Xie et al, 2021) and children (Chi et al, 2008). Furthermore, although IBV cases usually constitute about 1 / 4 of all cases, IBV viruses are predominant in some seasons (Ambrose and Levin, 2012;McCullers et al, 2004;Reed et al, 2012;Sun et al, 2019).…”

Cell-Adapted Mutations and Antigenic Diversity of Influenza B Viruses in Missouri, 2019–2020 Season

“…Of the IBVs, 97% belonged to subclade V1A.3 as compared with the B/Victoria vaccine reference strain (B/Colorado/06/2017) recommended by the WHO for the 2019-2020 season [54]. The B/Colorado/06/2017-like strain recommended by the WHO contains 2DEL at 162-163, which confers reduced hemagglutinin inhibition cross-reactivity against viruses with 3DEL [56]. However, most of the circulating strains (V1A.3 subclade) contained three amino acid deletions at positions 162-164 of the HA protein sequence [57].…”