Missed Opportunities for Vaccination and Associated Factors among Children Attending Primary Health Care Facilities in Cape Town, South Africa: A Pre-Intervention Multilevel Analysis

"The burden of MOV among children in Cape Town is influenced by individual and contextual factors, which provide important opportunities for quality improvement and broader strategies to improve routine immunisation service delivery."

South Africa is struggling to increase its national immunisation coverage. Sub-optimal coverage among children in the country has been attributed to individual-level factors, such as low awareness of the importance of immunisation, and to health system factors. Missed opportunities for vaccination (MOV) are defined as any contact with health services by an individual that does not result in the individual receiving all the vaccine doses for which she or he is eligible. This study assessed the magnitude of MOV and associated factors among children aged 0-23 months attending primary health care (PHC) facilities in Cape Town, South Africa.

The study, which used multilevel binomial logistic regression models, involved 674 children and their caregivers in urbanised metropolitan sub-districts. MOV prevalence was 14.1%, ranging from 9.1% to 18.9% across sub-districts. The prevalence of MOV was higher among children whose mothers did not attend antenatal care during pregnancy (50.0%), whose caregivers had low (primary) level of education (26.9%), who were in the health facilities for non-vaccination services (20.4%), whose primary caregivers did not receive any immunisation message in the last three months (19.6%), and whose caregivers walked to the health facility (i.e., did not have own transport) (17.1%).

Further analysis found that the likelihood of a child experiencing MOV was significantly associated with caregivers' low level of education (odds ratio (OR) = 3.53, 95% credible interval (CrI): 1.13-11.03), recent receipt of immunisation messages (OR = 0.46, 95% CrI: 0.25-0.87), shared immunisation decision making by both parents (OR = 0.21, 95% CrI: 0.07-0.62), and health facility staff number (OR = 0.18, 95%CrI: 0.06-0.61).

Reflecting on the findings, the researchers suggest some strategies to address the gaps identified in this study, including the following examples of communication-centred ones:

• Although many caregivers reported that health workers had asked to see their children's Road to Health Booklets (RtHB), the researchers found that health workers do not always screen the booklets for children's immunisation status at every visit. Interventions to foster routine immunisation status checks at all visits could help quickly identify children with missed vaccine doses. Possible approaches include placing reminder tags on children's RtHBs at the point of registration, placing posters/charts with MOV information prominently in consulting rooms, and instituting or strengthening routine supervision to improve RtHB screening compliance.
• The finding that MOV was associated with caregivers' implies the need for immunisation-themed health education interventions for parents, particularly those tailored to the intended audience's needs (e.g., in local languages). Such interventions can be implemented at both the facility level (e.g., through health talks in waiting rooms) and at the community level (e.g., through regular communication campaigns, particularly in communities with low childhood vaccination rates).
• Another notable finding of this study was the role of shared parental immunisation decision making as a determinant of MOV. A randomised controlled trial cited here found that a Japanese intervention that aimed to foster the involvement of fathers as co-decision makers with mothers improved immunisation rates and the percentage of parents intending to vaccinate their infants. Moreover, it is important to address existing parental or caregiver information gaps, such as those identified in the South African study, to share parental immunisation decision making for reducing MOV. Parents require access to good-quality immunisation information (such as information on the vaccines being administered, available options, health benefits, and risks of possible side effects) to make informed decisions on behalf of their child.

The paper also outlines implications for broader policy and practice, particularly in addressing the structural factors underlying MOV. For example:

• Policymakers need to consider policies that will enhance the efficient use of home-based records (HBRs), such as the RtHBs, for screening children's immunisation status. They could, for example, establish policy frameworks for regular in-service training to strengthen health workers' competencies in HBR screening, as well as prompt administration of catch-up immunisation for children with missing doses.
• The finding low educational attainment was associated with higher odds of MOV, which is consistent with findings from previous studies, suggests that system-wide efforts are needed to address the underlying social determinants of health. In addition, specific measures, such as locally adapted health education and immunisation messaging, tailored to the needs of vulnerable populations, such as socioeconomic disadvantaged communities, may help overcome barriers posed by factors such as parental low level of education.

After outlining opportunities for future study in this area, the researchers condlude that there is a substantial level of MOV among children in PHC settings in Cape Town. Individual- and contextual-level factors associated with MOV reflect the multi-dimensional nature of the problem, underscoring the need for remedial measures to not only reach out to individuals but also take into account socioeconomic and structural factors that exacerbate MOV.