Acceptance and feasibility of school-based seasonal influenza vaccination in Singapore: A qualitative study

Effectiveness of Multifaceted Strategies to Increase Influenza Vaccination Uptake: A Cluster Randomized Trial

Importance

Influenza vaccination rates remain low among primary school students and vary by school in Beijing, China. Theory-informed, multifaceted strategies are needed to improve influenza vaccination uptake.

Objective

To evaluate the effectiveness of multifaceted strategies in improving influenza vaccination uptake among primary school students.

Design, Setting, and Participants

This cluster randomized trial was conducted from September 2022 to May 2023 across primary schools in Beijing, China. Schools were allocated randomly in a 1:1 ratio to multifaceted strategies or usual practice. Schools were deemed eligible if the vaccination rates in the 2019 to 2020 season fell at or below the district-wide average for primary schools. Eligible participants included students in grades 2 and 3 with no medical contraindications for influenza vaccination.

Intervention

The multifaceted strategies intervention involved system-level planning and coordination (eg, developing an implementation blueprint, building social norms, and enhancing supervision), school-level training and educating school implementers (eg, conducting a 1-hour training and developing educational materials), and individual-level educating and reminding students and parents (eg, conducting educational activities and sending 4 reminders about vaccination).

Main Outcomes and Measures

The primary outcomes were influenza vaccination uptake at school reported by school clinicians as well as overall vaccine uptake either at school or outside of school as reported by parents at 3 months. Generalized linear mixed models were used for analysis.

Results

A total of 20 schools were randomized. One intervention school and 2 control schools did not administer vaccination on school grounds due to COVID-19, resulting in a total of 17 schools (9 intervention and 8 control). There was a total of 1691 students aged 7 to 8 years (890 male [52.6%]; 801 female [47.4%]) including 915 in the intervention group and 776 in the control group. Of all participants, 848 (50.1%) were in grade 2, and 1209 (71.5%) were vaccinated in the 2021 to 2022 season. Participants in the intervention and control groups shared similar characteristics. At follow-up, of the 915 students in the intervention group, 679 (74.5%) received a vaccination at school, and of the 776 students in the control group, 556 (71.7%) received a vaccination at school. The overall vaccination rates were 76.0% (695 of 915 students) for the intervention group and 71.3% (553 of 776 students) for the control group. Compared with the control group, there was significant improvement of vaccination uptake at school (odds ratio, 1.40; 95% CI, 1.06-1.85; P = .02) and overall uptake (odds ratio, 1.49; 95% CI, 1.12-1.99; P = .01) for the intervention group.

Conclusions and Relevance

In this study, multifaceted strategies showed modest effectiveness in improving influenza vaccination uptake among primary school students, which provides a basis for the implementation of school-located vaccination programs of other vaccines in China, and in other countries with comparable programs.

Trial registration

Chinese Clinical Trial Registry: ChiCTR2200062449.

Assessing the longitudinal effects of the continuation and discontinuation of the school-located influenza vaccination programme on parental vaccine hesitancy in Hong Kong

BACKGROUND

School-located influenza vaccination programme (SIVP) can effectively promote childhood seasonal influenza vaccination (SIV). However, the longitudinal effects of continuation and discontinuation of the SIVP on parents' vaccine hesitancy remained unknown.

METHODS

A two-wave longitudinal study recruited adult parents who had at least one child attending a kindergarten or primary school using random-digital-dialled telephone interviews. Generalized estimating equation and structural equation modelling were used to examine the impact of changes in schools' SIVP participation status on parents' vaccine-related attitudes, and childhood SIV acceptance over 2 years in Hong Kong.

RESULTS

Children's SIV uptake varied by the schools' SIVP participation status. The highest SIV uptake was found in schools that consistently participated in SIVP (Consistent participation group) (2018/2019: 85.0%; 2019/2020: 83.0%) but lowest in the Consistent non-Participation group (2018/2019: 45.0%; 2019/2020: 39.0%). SIV uptake increased in the Late Initiation group but declined in the Discontinuation group. An increasing trend of parental vaccine-hesitant attitudes was observed in the Consistent non-Participation group.

CONCLUSIONS

Initiation and continuation of the SIVP can reduce parental vaccine hesitancy to achieve a high childhood SIV uptake. Conversely, discontinuation of the SIVP or persistent resistance to the implementation of SIVP can increase parental vaccine hesitancy and reduce childhood SIV uptake.

Determinants of influenza and pneumococcal vaccine uptake among preschool children in Singapore

Young children are at increased risk of severe illness from influenza and pneumococcal infections. The World Health Organization (WHO) recommends vaccination with influenza and pneumococcal conjugate vaccine (PCV). However, in Singapore, vaccine uptake remains suboptimal relative to other routine childhood immunisations. Limited information exists regarding determinants of influenza and pneumococcal vaccine uptake in children. We estimated vaccine uptake and investigated factors associated with influenza and pneumococcal vaccination status by age group using data from a cohort study on acute respiratory infections in children attending preschools in Singapore. We recruited children aged two to six years at 24 participating preschools from June 2017 to July 2018. We determined the proportion of children immunised with influenza vaccine and PCV, and investigated socio-demographic factors associated with vaccine uptake using logistic regression models. Among 505 children, 77.5% were of Chinese ethnicity, and 53.1% were male. History of influenza vaccination was 27.5% of which 11.7% had been vaccinated within the past 12 months. In multivariable analyses, factors associated with influenza vaccine uptake were 'children living in landed property' (aOR = 2.25, 95% CI [1.07-4.67]) and 'history of hospitalisation due to cough' (aOR = 1.85, 95% CI [1.00-3.36]). Nearly three-quarters of participants (70.7% 95%CI: [66.6-74.5]) reported prior PCV vaccination. PCV uptake was higher for younger children. 'Higher parental education' (OR = 2.83, 95% CI [1.51,5.32]), 'household income' (OR = 1.26, 95% CI [1.08,1.48]) and 'smokers in household' (OR = 0.48, 95% CI [0.31,0.74]) were significantly associated with PCV uptake in univariable analyses. Only 'smokers in household' remained significantly associated with PCV uptake (aOR = 0.55, 95% CI [0.33,0.91]) in the adjusted model. Our results indicate that episodes of severe respiratory illness are a cue to influenza vaccination suggesting that doctors are more likely to recommend influenza vaccines to high-risk children. For PCV, our findings suggest overall greater awareness and education on the benefit of PCV vaccination is required.