Effectiveness of Catch-Up Vaccination Interventions Versus Standard or Usual Care Procedures in Increasing Adherence to Recommended Vaccinations Among Different Age Groups

"Active vaccine catch-up interventions can be an extremely useful tool for improving adherence to vaccination practices. Experience and research can help identify the most effective vaccination strategies."

Globally, decline in vaccinations threatens to strain health systems with outbreaks of vaccine-preventable diseases. Several attempts have been made to identify approaches that increase immunisation coverage, such as vaccine information campaigns, promotional and educational messages for patients and healthcare professionals, and the use of reminders and various mobile apps. This systematic review and meta-analysis aims to evaluate vaccine adherence across various catch-up methods designed to reach different age groups. In addition, it sought to identify the most effective vaccination recall strategies compared with standard or usual care procedures, based on randomised controlled trials (RCTs) and before-after studies.

The paper explains the various types of strategies for boosting vaccination coverage covered by the reviewed studies;
 

• Reminder and recall interventions are used to prompt individuals within a certain population regarding upcoming vaccinations (recall) or overdue vaccinations (reminder). These strategies vary in content based on the type of vaccination and the priority demographic. They are implemented through various methods, including: telephone calls with active reminders; messaging via SMS (text messages), emails, or traditional mails; in-person reminders within clinical settings; the use of physical objects as reminders; and reminders via web-based platforms.
• Lack of knowledge and misinformation stand as the primary barriers impeding widespread access to vaccination. Addressing these challenges necessitates a shift toward a more suitable educational approach within the vaccination context.
• The multidimensional approach encompasses interventions that combine vaccination reminder tools with awareness sessions and patient education on vaccination. These interventions are implemented through multiple steps and in various formats.

In February 2022, 2 databases were consulted, retrieving 1,850 studies. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, 79 manuscripts were included after the assessment phase. These comprised 46 trials/RCTs and 33 before-after studies. Of the included RCTs, 20 studies (43%) were conducted on the American continent, 11 studies (24%) in Asia, 9 studies (20%) in Europe, 5 studies (11%) in Africa, and 1 study in Australia. The selected outcome was the risk ratio (RR) of vaccination coverage improvement effectiveness.

The analyses showed an overall efficacy of RR 1.22 (95% confidence interval (CI) 1.19-1.26) for RCTs and RR 1.70 (95% CI 1.54-1.87) for before-after studies when considering all interventions cumulatively. Subgroup analyses identified multicomponent interventions (RR 1.58, 95% CI 1.36-1.85) and recall clinical interventions (RR 1.24, 95% CI 1.17-1.32) as the most effective in increasing vaccination coverage for RCTs. By contrast, educational interventions (RR 2.13, 95% CI 1.60-2.83) and multicomponent interventions (RR 1.61, 95% CI 1.43-1.82) achieved the highest increases for before-after studies. Particularly, among the selected educational interventions, those based on face-to-face dialog between patients and healthcare professionals emerge as the most effective.

The meta-regression results also revealed the effectiveness of various interventions aimed at vaccination catch-up among a specific demographic: middle-aged adults. Specifically, meta-regression analyses indicated that the middle-aged adult population was associated with a higher increase in vaccination coverage (RCT: coefficient 0.54, 95% CI 0.12-0.95; before-after: coefficient 1.27, 95% CI 0.70-1.84). This finding may be attributed to the organisation of vaccination services by age group. Historically, the majority of vaccines have been developed for paediatric populations, and extensive national and international collaborative efforts have strongly supported mass immunisation of the youngest individuals. Conversely, reaching the adult population with standard vaccine delivery methods can be more challenging. However, catch-up vaccination and recall interventions have the potential to be highly effective in enhancing coverage among adults.

In conclusion: "Vaccination reminder interventions, incorporating educational sessions for the population and utilizing various reminder methods such as SMS text messages and calls, as well as multifaceted interventions combining multiple strategies, have demonstrated effectiveness in enhancing vaccination coverage. However, it is important to note that there is no universal catch-up strategy that performs well across all contexts and realities. It is essential to adopt the most suitable intervention strategy based on the patient category, resource availability, and the socioeconomic status of the target population to be vaccinated."