BMC Public Health . Can uptake of childhood influenza immunisation through schools and GP practices be increased through behaviourally-informed invitation letters and reminders: two pragmatic randomized controlled trials

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BMC Public Health


. 2023 Jan 20;23(1):143.
doi: 10.1186/s12889-022-14439-4.
Can uptake of childhood influenza immunisation through schools and GP practices be increased through behaviourally-informed invitation letters and reminders: two pragmatic randomized controlled trials


Rebecca Howell-Jones ¹ , Natalie Gold ^{2 3 4} , Sarah Bowen ^{1 5 6} , Amanda Bunten ¹ , Karen Tan ¹ , Ayoub Saei ⁷ , Sarah Jones ⁸ , Pauline MacDonald ^{9 10} , Robin Watson ^{1 11 12} , Kirsty F Bennett ^{1 12 13} , Tim Chadborn ¹



Affiliations

• PMID: 36670376
• PMCID: PMC9854224
• DOI: 10.1186/s12889-022-14439-4

Free PMC article

Abstract

Background: The UK is rolling out a national childhood influenza immunisation programme for children, delivered through primary care and schools. Behaviourally-informed letters and reminders have been successful at increasing uptake of other public health interventions. Therefore, we investigated the effects of a behaviourally-informed letter on uptake of the vaccine at GP practices, and of a letter and a reminder (SMS/ email) on uptake at schools.
Methods and results: Study 1 was a cluster-randomised parallel trial of 21,786 two- and three-year olds in 250 GP practices, conducted during flu season (September to January inclusive) 2016/7. The intervention was a centrally-sent behaviourally-informed invitation letter, control was usual care. The proportion of two- and three-year olds in each practice who received a vaccination by 31st January 2017 was 23.4% in the control group compared to 37.1% in the intervention group (OR = 1.93; 95% CI = 1.82, 2.05, p < 0.001). Study 2 was a 2 (behavioural letter vs standard letter) × 2 (reminder vs no reminder) factorial trial of 1108 primary schools which included 3010 school years 1-3. Letters were sent to parents from providers, and reminders sent to parents from the schools. In the standard-letter-no-reminder arm, an average of 61.6% of eligible children in each school year were vaccinated, compared to 61.9% in the behavioural-letter-no-reminder arm, 63.5% in the standard-letter-plus-reminder arm, and 62.9% in the behavioural-letter-plus reminder condition, F(3, 2990) = 2.68, p = 0.046. In a multi-level model, with demographic variables as fixed effects, the proportion of eligible students in the school year who were vaccinated increased with the reminder, β = 0.086 (0.041), p < 0.036, but there was no effect of the letter nor any interaction effect.
Conclusion: Sending a behaviourally informed invitation letter can increase uptake of childhood influenza vaccines at the GP surgery compared to usual practice. A reminder SMS or email can increase uptake of the influenza vaccine in schools, but the effect size was minimal.
Trial registration: Study 1: Trial registration: ClinicalTrials.gov Identifier: NCT02921633. Study 2: Trial registration: ClinicalTrials.gov Identifier: NCT02883972.

Keywords: Behaviourally-informed invitation letter; Childhood flu; Influenza immunization; Primary care; Text message reminders; UK childhood influenza immunisation programme; Vaccination.