Uptake and impact of vaccinating primary school-age children against influenza: experiences of a live attenuated influenza vaccine programme, England, 2015/16

Abstract

The 2015/16 influenza season was the third season of the introduction of an intra-nasally administered live attenuated influenza vaccine (LAIV) for children in England. All children aged 2‒6 years were offered LAIV, and in addition, a series of geographically discrete areas piloted vaccinating school-age children 7‒11 years old. Influenza A(H1N1)pdm09 was the dominant circulating strain during 2015/16 followed by influenza B. We measured influenza vaccine uptake and the overall and indirect effect of vaccinating children of primary school -age, by comparing cumulative disease incidence in targeted and non-targeted age groups in vaccine pilot and non-pilot areas in England. Uptake of 57.9% (range: 43.6-72.0) was achieved in the five pilot areas for children aged 5‒11 years. In pilot areas, cumulative emergency department respiratory attendances, influenza-confirmed hospitalisations and intensive care unit admissions were consistently lower, albeit mostly non-significantly, in targeted and non-targeted age groups compared with non-pilot areas. Effect sizes were less for adults and more severe endpoints. Vaccination of healthy primary school-age children with LAIV at moderately high levels continues to be associated with population-level reductions in influenza-related respiratory illness. Further work to evaluate the population-level impact of the programme is required.

Influenza A haemagglutinin specific IgG responses in children and adults after seasonal trivalent live attenuated influenza vaccination

“…and drifted B strain [275]. The following season was dominated by influenza A/H1N1pdm09 but reduced influenza infection was observed among the vaccinated school-age children [276]. The A/H1N1pdm09 was from the new genetic subgroup (6B.1 and 6B.2) during this season and thus LAIV vaccine effectiveness was reported against a mismatched strain [277].…”

Infection is associated with one in five childhood deaths in England and Wales: analysis of national death registrations data, 2013–15

“…Among viral infections, influenza-related deaths occurred across all age groups. In the UK, the live attenuated influenza vaccine has been recommended for those aged 2–17 years and is currently offered to toddlers and primary school-age children, providing direct and indirect protection across all age groups 15. The small reduction in childhood influenza-related deaths from 30 cases during 2003–05 to 20 in 2013–15 could be due to the programme, but numbers are too small for formal statistical analysis.…”

Functional immune response to influenza H1N1 in children and adults after live attenuated influenza virus vaccination

“…LAIV has been shown to induce broader protection in ferrets and in children when used in a school setting . Furthermore, the inclusion of LAIV in the childhood vaccination programme in the UK has shown the benefits of herd immunity, which are thought to be mediated by T cells . Therefore, the use of LAIV in children could be an important step in the protection against novel drifted or pandemic strains.…”