Scotland and the UK have long-standing influenza selective immunisation programmes offering inactivated vaccine to people 65 years of age and older and those six months and over with an underlying clinical risk factor. Following advice from the Joint Committee on Vaccination and Immunisation (JCVI), the UK started the incremental introduction of a universal childhood influenza vaccine programme in the 2013/14 influenza season with a newly licensed intra-nasally administered live attenuated influenza vaccine (LAIV). Eligible healthy children were offered a single dose of LAIV, whereas children in a clinical risk group up to nine years of age, with no contraindications for LAIV and not previously vaccinated, were offered two doses of vaccine. By the 2016/17 season, all children aged two to eight across the UK were being offered quadrivalent LAIV (LAIV4), or else quadrivalent inactivated vaccine (QIV) where LAIV4 was contraindicated. In addition, Scotland and Northern Ireland offered LAIV4 also to all remaining children of primary school age up to 11 years of age.
An analysis published in the current issue of Eurosurveillance (at http://www.eurosurveillance.org/content/eurosurveillance/22/44) is thought to provide encouraging results for the new UK childhood influenza vaccine programme using LAIV4, albeit in a season dominated by A(H3N2) no significant effectiveness of inactivated influenza vaccine (IIV) was demonstrated in adults aged 65 and over. The level of LAIV4 effectiveness observed in 2016/17 combined with uptake in children should maximise the population level benefits of the programme. These benefits are projected to provide direct protection to those vaccinated, and by reducing children’s rates of infection, to indirectly protect more vulnerable members of their families and communities, in particular those who belong to a clinical at-risk group and older adults. Although moderate protection was seen in younger adults, no significant effectiveness was seen in the latter group. The findings continue to provide support for the ongoing roll-out of the paediatric vaccine programme, with a need for ongoing evaluation. The importance of effective interventions to protect the ≥ 65-year-olds remains.
The authors consider that the findings in both children and those aged 65 years and above will need further epidemiological and virological investigation. Particularly for the former age group, the results from a season dominated by circulation of influenza A(H1N1)pdm09 viruses will be critically important to provide on-going assurance of the optimal design of the UK programme.