Effectiveness of seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: 2014/15 end of season results

Abstract

The 2014/15 influenza season in the United Kingdom (UK) was characterised by circulation of predominantly antigenically and genetically drifted influenza A(H3N2) and B viruses. A universal paediatric influenza vaccination programme using a quadrivalent live attenuated influenza vaccine (LAIV) has recently been introduced in the UK. This study aims to measure the end-of-season influenza vaccine effectiveness (VE), including for LAIV, using the test negative case-control design. The overall adjusted VE against all influenza was 34.3% (95% confidence interval (CI) 17.8 to 47.5); for A(H3N2) 29.3% (95% CI: 8.6 to 45.3) and for B 46.3% (95% CI: 13.9 to 66.5). For those aged under 18 years, influenza A(H3N2) LAIV VE was 35% (95% CI: -29.9 to 67.5), whereas for influenza B the LAIV VE was 100% (95% CI:17.0 to 100.0). Although the VE against influenza A(H3N2) infection was low, there was still evidence of significant protection, together with moderate, significant protection against drifted circulating influenza B viruses. LAIV provided non-significant positive protection against influenza A, with significant protection against B. Further work to assess the population impact of the vaccine programme across the UK is underway.

M2SR, a novel live single replication influenza virus vaccine, provides effective heterosubtypic protection in mice

“…These promising results suggest that M2SR could offer a major advantage over currently approved vaccines, which offer little or no protection against newly emerging or mutated strains [22, 23]. Whereas LAIV has provided protection in children in seasons in which the antigenicity of the virus has drifted [3–5, 24], recent studies suggest that LAIV may not be as effective in adults due to preexisting immunity [9, 25]. M2SR can be produced efficiently in cell culture, avoiding the many disadvantages of production in eggs.…”

“…Thus, these vaccines are not effective if they are poorly-matched to circulating strains, as occurred recently in the 2014/2015 flu season [2]. Although LAIV has previously demonstrated protection in seasons with antigenically mismatched vaccines in children [3–5], accumulating data suggest that effective immune responses are mitigated by the pre-existing immunity present in most adults [6–8]. Thus, current vaccines offer little protection against antigenically distinct strains which have the potential to cause influenza pandemics.…”

Summary of the NACI Statement on Seasonal Influenza Vaccine for 2017–2018

“…These studies used the test-negative design (21)(22)(23)(24)(25)(26), with one prospective cohort study (27) and two cluster randomized trials (28,29).…”

Sommaire de la Déclaration du CCNI sur la vaccination antigrippale pour la saison 2017-2018

“…Bien que le fardeau de la grippe puisse varier d'une année à l'autre, il est estimé que dans une année donnée, il y a en moyenne 12 200 hospitalisations (2) et environ 3 500 décès attribuables à la grippe (3 (27). Ces études utilisaient la méthode de diagnostic de test négatif (21)(22)(23)(24)(25)(26), avec une étude de cohorte prospective (27) et deux essais cliniques randomisés par grappes (28,29).…”