Pandemic H1N1 influenza vaccine(Institute Of Experimental Medicine Of The Russian Academy Of Medical Sciences)

Influenza is known to predispose to secondary bacterial infections including invasive group A streptococcal (iGAS) disease. The universal pediatric live attenuated influenza vaccine (LAIV) program introduced in England from the 2013/2014 influenza season was implemented incrementally, introducing cohorts of children annually to 2-16 years of coverage. Additionally, from the beginning of the program, discrete pilot areas offered LAIV vaccination to all primary school-age children, allowing for a unique comparison of infection rates between pilot and nonpilot areas during the program rollout.

Cumulative incidence rate ratios (IRRs) of GAS infections (all), scarlet fever (SF), and iGAS infection within each season by age group were compared for pilot and nonpilot areas using Poisson regression. The overall effect of the pilot program in the pre- (2010/2011-2012/2013 seasons) and postintroduction (2013/2014-2016/2017 seasons) periods was assessed using negative binomial regression by comparing changes in incidence between pilot/nonpilot areas (ratio of IRR [rIRR]).

Reductions in IRRs of GAS and SF were observed within most post-LAIV program seasons, among the age groups 2-4 and 5-10 years. Significant reductions were seen among 5-10 years (rIRR, 0.57; 95% CI, 0.45-0.71; P < .001), 2-4 years (rIRR, 0.62; 95% CI, 0.43-0.90; P = .011), and 11-16 years (rIRR, 0.63; 95% CI, 0.43-0.90; P = .018) for GAS infections when assessing the overall effect of the program.

Our findings suggest that vaccination with LAIV may be associated with a reduced risk of GAS infection and support attaining high uptake of childhood influenza vaccination.

The universal paediatric live attenuated influenza vaccine (LAIV) programme commenced in the United Kingdom (UK) in 2013/2014. Since 2014/2015, all pre‐school and primary school children in Scotland and Northern Ireland have been offered the vaccine. England and Wales incrementally introduced the programme with additional school age cohorts being vaccinated each season. The Republic of Ireland (ROI) had no universal paediatric programme before 2017. We evaluated the potential population impact of vaccinating primary school‐aged children across the five countries up to the 2016/2017 influenza season.

We compared rates of primary care influenza‐like illness (ILI) consultations, confirmed influenza intensive care unit (ICU) admissions, and all‐cause excess mortality using standardised methods. To further quantify the impact, a scoring system was developed where each weekly rate/z‐score was scored and summed across each influenza season according to the weekly respective threshold experienced in each country.

Results highlight ILI consultation rates in the four seasons' post‐programme, breached baseline thresholds once or not at all in Scotland and Northern Ireland; in three out of the four seasons in England and Wales; and in all four seasons in ROI. No differences were observed in the seasons' post‐programme introduction between countries in rates of ICU and excess mortality, although reductions in influenza‐related mortality were seen. The scoring system also reflected similar results overall.

Findings of this study suggest that LAIV vaccination of primary school age children is associated with population‐level benefits, particularly in reducing infection incidence in primary care.