Epidemiological Impact of the Pediatric Live Attenuated Influenza Vaccine (LAIV) Program on Group A Streptococcus (GAS) Infection in England

Background

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.

Methods

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]).

Results

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.

Conclusions

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.

Impact of the childhood influenza vaccine programme on antibiotic prescribing rates in primary care in England

Vaccines are a key part of the global strategy to tackle antimicrobial resistance (AMR) since prevention of infection should reduce antibiotic use. England commenced national rollout of a live attenuated influenza vaccine (LAIV) programme for children aged 2-3 years together with a series of geographically discrete pilot areas for primary school age children in 2013 extending to older children in subsequent seasons. We investigated vaccine programme impact on community antibiotic prescribing rates. Antibiotic prescribing incidence rates for respiratory (RTI) and urinary tract infections (UTI; controls) were calculated at general practice (GP) level by age category (children<=10 years/adults) and season for LAIV pilot and non-pilot areas between 2013/14 and 2015/16. To estimate the LAIV (primary school age children only) intervention effect, a random effects model was fitted. A multivariable random-effects Poisson regression investigated the association of antibiotic prescribing rates in children with LAIV uptake (2-3-year-olds only) at GP practice level. RTI antibiotic prescribing rates for children <=10 years and adults showed clear seasonal trends and were lower in LAIV-pilot and non-pilot areas after the introduction of the LAIV programme in 2013. The reductions for RTI prescriptions (children) were similar (within 3%) in all areas, which coincided with the start the UK AMR strategy. Antibiotic prescribing was significantly (p < 0.0001) related to LAIV uptake in 2-3-year-olds with antibiotic prescribing reduced by 2.7% (95% CI: 2.1% to 3.4%) for every 10% increase in uptake. We found no evidence the LAIV programme for primary school age children resulted in reductions in RTI antibiotic prescribing, however we detected a significant inverse association between increased vaccine uptake in pre-school age children and antibiotic prescribing at GP level. The temporal association of reduced RTI and UTI antibiotic prescribing with the launch of the UK's AMR Strategy in 2013 highlights the importance of a multifaceted approach to tackle AMR.

Influenza vaccine uptake among at-risk adults (aged 16-64 years) in the UK: a retrospective database analysis

Background

In the UK, annual influenza vaccination is currently recommended for adults aged 16–64 years who are in a clinical at-risk group. Despite recommendations, rates of vaccine uptake in the UK have historically been low and below national and international targets. This study aims to analyse vaccine uptake among adults in clinical at-risk groups from the 2015–2016 influenza season to the present.

Methods

A retrospective analysis of influenza vaccine coverage in the UK was conducted using data extracted from publicly available sources. Clinically at-risk individuals (as defined by Public Health England), including pregnant women, aged 16–64 years, were included in this study.

Results

Influenza vaccination coverage rates across the UK in adults aged 16–64 years in a clinical at-risk group have been consistently low over the past 5 years, with only 48.0, 42.4, 44.1 and 52.4% of eligible patients in England, Scotland, Wales and Northern Ireland receiving their annual influenza vaccination during the 2018–2019 influenza season. Influenza vaccine coverage was lowest in patients with morbid obesity and highest in patients with diabetes in 2018–2019. Coverage rates were below current national ambitions of ≥75% in all clinical risk groups. In these clinical at-risk groups, influenza vaccine coverage decreased between 2015 and 2019, and there was considerable regional variation.

Conclusions

Uptake of the influenza vaccine by adults aged 16–64 years in a clinical at-risk group was substantially below the national ambitions. As a result, many individuals in the UK remain at high risk of developing severe influenza or complications. Given that people who are vulnerable to COVID-19 are also at increased risk of complications from influenza, during the 2020–2021 season, there is a heightened need for healthcare professionals across the UK to address suboptimal vaccine uptake, particularly in at-risk patients. Healthcare professionals and policymakers should consider measures targeted at increasing access to and awareness of the clinical benefits of the influenza vaccine.

Uptake and impact of vaccinating primary school children against influenza: Experiences in the fourth season of the live attenuated influenza vaccination programme, England, 2016/2017

Background

In the 2016/2017 influenza season, England was in its fourth season of the roll‐out of a live‐attenuated influenza vaccine (LAIV) targeted at healthy children aged two to less than 17 years. For the first time, all healthy children aged 2 to 8 years were offered LAIV at national level in 2016/2017. Since the commencement of the programme in 2013/2014, a series of geographically discrete pilot areas have been in place where quadrivalent LAIV was also offered to all school age children. In 2016/2017, these were children aged 8 to 11 years, other than those targeted by the national programme.

Methods

We evaluated the overall and indirect impact of vaccinating primary school age children, on the population of England, by measuring vaccine uptake levels and comparing cumulative disease incidence through various influenza surveillance schemes, in targeted and non‐targeted age groups in pilot and non‐pilot areas in 2016/2017.

Results

Our findings indicate that cumulative primary care influenza‐like consultations, primary and secondary care swab positivity, influenza confirmed hospitalisations and emergency department attendances in pilot areas were overall lower than those observed in non‐pilot areas; however, significant differences were not always observed in both targeted and non‐targeted age groups. Excess mortality was higher in pilot areas compared with non‐pilot areas.

Conclusions

These results are similar to earlier seasons of the programme indicating the importance and continuing support of vaccinating all primary school children with LAIV to reduce influenza related illness across the population, although further work is needed to understand the differences in excess mortality.