Systematic Review on Reducing Missed Opportunities for Vaccinations in Latin America

"The results of this review suggest an important rate of MOVs [missed opportunities for vaccination] in the Region."

Vaccine coverage in Latin America and the Caribbean has considerably decreased since 2013, less than half of countries in the Region reached the World Health Organization (WHO) 90% coverage target in 2017, and coverage continues to vary dramatically between countries in the Region. A number of challenges impede vaccination coverage in the Region, including hard-to-reach communities, political instability, unfavourable socioeconomic factors, religious/cultural beliefs, vaccine hesitancy, limited resources, poor management of health systems, and inadequate monitoring and supervision. WHO recommends that immunisation should be offered to all eligible individuals at every contact point with health services. When it is not offered, this is referred to as a "missed opportunity for vaccination" (MOV). This systematic review sought to estimate the prevalence of MOV in Latin America and the effect of interventions targeting health systems, health workers, patients, and communities on MOV.

Searches were conducted in MEDLINE, EMBASE, CINAHL, and LILACS electronic databases, and relevant organisations were contacted, including the Pan American Health Organization (PAHO), to identify studies meeting eligibility criteria. A pair of reviewers identified 27 randomised and non-randomised studies quantifying the effectiveness of any intervention for reducing MOV and 5 studies assessing the rate of MOV in Latin America. Results are reported narratively when criteria to pool results were not met, and the certainty of this evidence was assessed using the GRADE approach.

Evidence indicates that the rate of MOV in Latin America ranged from 5% to 37%, with a pooled estimate of 17% (95% confidence interval (CI) 9, 32) (low certainty). The certainty of the evidence on interventions for reducing MOVs ranged from very low to moderate certainty, and it included:
 

• Interventions engaging the healthcare team (8 studies): There was moderate-certainty evidence that monetary incentives (7.5% reduction in MOVs) and training on how to communicate with patients (relative risk (RR) 0.97; 95% CI [0.95, 0.98]) probably reduce MOVs. There was low-certainty evidence suggesting that reminders attached to medical records (RR 0.50; 95% CI [0.19, 1.33] from RCTs) may reduce MOVs, that educational interventions and performance feedback may reduce MOVs (RR 0.27; 95% CI [0.20, 0.36]), and that educational interventions may reduce MOVs (RR 0.56; 95% CI [0.35, 0.88]).
• Interventions engaging patients or caregivers (7 studies): There was moderate-certainty evidence that educational interventions likely reduce MOVs (RR 0.89; 95% CI [0.73, 1.09]). There was low-certainty evidence suggesting that monetary fines may reduce MOVs (RR 0.87; 95% CI [0.80, 0.94]). The certainty of evidence was very low for reminders and alerts, either mailed or by telephone and SMS (short message service).
• Interventions directed toward the healthcare system (5 studies): There was low-certainty evidence suggesting that ensuring presence of a pharmacist (OR 0.56; 95% CI [0.35, 0.90]) and offering free vaccination programmes (RR 1.00; 95% CI [0.95, 1.05]) may reduce MOVs.

Implications for research are outlined. The researchers suggest the development of higher-quality randomised and non-randomised studies on interventions for reducing MOVs, especially in low- or middle-income countries (or those with lower vaccination coverage) and in the context of issues associated with access to care, vaccine hesitancy, and the COVID-19 pandemic. They encourage testing of cross-cutting health system changes, interventions targeting vaccine hesitancy, and community-level interventions. In addition, uniform definitions of MOVs should be adopted to promote comparability of studies.

In terms of implications for practice and policy, the researchers urge that effort be made to consider interventions for reducing MOVs while maintaining the trust of populations in the Region in vaccination services. "Now more than ever, ensuring that every child who accesses a health center has their vaccination status reviewed and their vaccination schedule completed will be an opportunity to improve vaccination coverage and reduce incidence of vaccine-preventable diseases..."

In conclusion: "Clinicians and other decisionmakers within the Region should consider this review's limitations, paucity of evidence on patient-important outcomes, and the influence of several other factors (including costs, feasibility, acceptability, and equity) before implementing interventions for reducing MOVs (monetary incentives to healthcare teams, training healthcare teams on patient communication, and educational interventions for caregivers) at an individual or population level."