Interventions to Enhance Adherence to COVID-19 Booster Vaccinations: A Systematic Review

Abstract

COVID-19 booster vaccinations are pivotal in the ongoing management of the pandemic. However, their acceptance rates have declined, and evidence of effective interventions targeting booster doses remains limited. This study aimed to identify, summarise, and evaluate strategies to enhance adherence to COVID-19 booster vaccinations. A systematic review included primary quantitative or qualitative studies that reported interventions to improve adherence to COVID-19 booster vaccinations. Articles published between January 1, 2020, and August 5, 2024, were identified through MEDLINE, SCOPUS, Web of Science Core Collection (via Clarivate), EMBASE (via Elsevier), and APA PsycINFO (via EBSCO). The risk of bias was assessed using the Mixed Methods Appraisal Tool (MMAT), and data were synthesised narratively. Outcome measures included vaccination uptake and intention to vaccinate. The review protocol was registered in PROSPERO (CRD42024575826). A total of 26 articles, encompassing 4,089,928 participants, met the inclusion criteria. Of these, 20 were assessed as high-quality studies. Interventions were categorised into communication strategies, policy interventions, multidimensional interventions, educational interventions, and incentives. Twelve studies measured COVID-19 booster uptake, 12 assessed intention to vaccinate, and two evaluated both outcomes. Narrative synthesis revealed that the most effective interventions included text reminders, educational activities, and multidimensional approaches, demonstrating significant improvements in vaccination rates and intentions. Future research should prioritise identifying cost-effective and sustainable interventions, particularly tailored to diverse populations, to enhance adherence to COVID-19 booster vaccinations.