Efficacy of Inactivated Vaccine in Preventing Antigenically Drifted Influenza Type A and Well-Matched Type B

Abstract

Our data suggest that current inactivated vaccine is highly effective for protection against influenza type A(H3N2) virus infection regardless of antigenic drift. In contrast, the protective efficacy obtained by vaccination may not be sufficient against influenza type B virus infection, and especially in young children, it does not offer protection.

Potential impact of B lineage mismatch on trivalent influenza vaccine effectiveness during the 2015–2016 influenza season among nursery school children in Suzhou, China

“…8 Vaccine efficacy from randomized control trials and vaccine effectiveness from observational studies among healthy children in developed countries has ranged from 40%¡70%. [9][10][11] Similar findings were reported in several seasons in China when circulating influenza viruses were well-matched to vaccine strains. [12][13][14][15] Improving our understanding of how to effectively prevent influenza infection among nursery school children is particularly important given that children in this age group have a longer duration of pre-and post-symptomatic influenza virus shedding than adults 16 and, therefore, may infect family members and classmates prior to symptom onset.…”

Prevention and Control of Seasonal Influenza with Vaccines

“…In the pediatric literature, most published studies of this nature focus on asthma. In a nonrandomized controlled trial during the 1992-93 season involving 137 children who had moderate to severe asthma, vaccine efficacy against laboratory-confirmed influenza A(H3N2) infection was 54% among children aged 2 through 6 years and 78% among children aged ≥7 through 14 years; vaccine efficacy against laboratory-confirmed influenza B infection was 60% among children aged ≥7 through 14 years, but nonsignificant for the younger age group (193). In a two-season study of 349 asthmatic children, IIV3 vaccine was associated with a 55% reduction in the occurrence of ARI in children aged <6 years (95% CI = 20-75; p = 0.01), but no association was noted among children aged 6 through 12 years (194).…”

Influenza Vaccine Effectiveness for Fully and Partially Vaccinated Children 6 Months to 8 Years Old During 2011–2012 and 2012–2013

“…Some studies have reported significant VE for fully vaccinated children only [21–24], while others have observed similar VE for fully and partially vaccinated children in some age groups [23, 25–28]. Most of these studies have examined VE against all circulating influenza strains [21, 23, 25, 26]; few have been able to consider the importance of full vaccination against a specific influenza type or subtype [19, 24, 27, 29, 30]. …”