Effectiveness of seasonal influenza vaccine for adults and children in preventing laboratory-confirmed influenza in primary care in the United Kingdom: 2015/16 end-of-season results

Abstract

The United Kingdom (UK) is in the third season of introducing universal paediatric influenza vaccination with a quadrivalent live attenuated influenza vaccine (LAIV). The 2015/16 season in the UK was initially dominated by influenza A(H1N1)pdm09 and then influenza of B/Victoria lineage, not contained in that season’s adult trivalent inactivated influenza vaccine (IIV). Overall adjusted end-of-season vaccine effectiveness (VE) was 52.4% (95% confidence interval (CI): 41.0–61.6) against influenza-confirmed primary care consultation, 54.5% (95% CI: 41.6–64.5) against influenza A(H1N1)pdm09 and 54.2% (95% CI: 33.1–68.6) against influenza B. In 2–17 year-olds, adjusted VE for LAIV was 57.6% (95% CI: 25.1 to 76.0) against any influenza, 81.4% (95% CI: 39.6–94.3) against influenza B and 41.5% (95% CI: −8.5 to 68.5) against influenza A(H1N1)pdm09. These estimates demonstrate moderate to good levels of protection, particularly against influenza B in children, but relatively less against influenza A(H1N1)pdm09. Despite lineage mismatch in the trivalent IIV, adults younger than 65 years were still protected against influenza B. These results provide reassurance for the UK to continue its influenza immunisation programme planned for 2016/17.

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

“…This article also presents information not provided in the published addenda or statement: figures summarizing the LAIV vaccine effectiveness data from the cited studies, by influenza season and influenza strain, as well as LAIV vaccine effectiveness data used to inform NACI's decision that were not publicly available when the Addendum was finalized, but have subsequently been published (30,31).…”

Live attenuated influenza vaccine (LAIV): recent effectiveness results from the USA and implications for LAIV programmes elsewhere

“…In children 2–17 years of age, LAIV4-adjusted VE in the UK was 57% overall (significant), 41.5% (non-significant) for A(H1N1)pdm09% and 81.4% (significant) for influenza B. These findings compare with estimates of 100% (significant) and 56.3% (non-significant) for IIV effectiveness against A(H1N1)pdm09 and B, respectively, in children 2. Similar results were seen for protection against influenza-confirmed hospitalisation in both England and Scotland 21 22…”

In this issue: tools and processes that translate knowledge into practice

“…However, up to 2013, its work was limited to reporting on influenza,14 infectious disease15 and vaccine effectiveness 16. More recently, it has extended its remit into diabetes and other non-communicable diseases 17.…”