Correlates of Full, Partial, and Non-Immunisation among Children Aged 12–23 Months in Gokwe South District, Rural Zimbabwe

Study design and setting

This was a community‑based cross‑sectional study conducted in Gokwe District, a predominantly rural district in the Midlands Province of Zimbabwe [13, 14]. The district is characterised by dispersed settlements, limited transportation networks, high poverty, and reliance on subsistence farming [13]. Health services are delivered through clinics, rural hospitals, and outreach points supported by village health workers.

Study population

The study population comprised caregivers of children aged 12–23 months, residing in Gokwe South District for at least 6 months prior to the survey. Children younger than 12 months were excluded to avoid misclassification of incomplete schedules.

Sampling procedure

A multistage sampling approach was employed. In the first stage, health facilities providing routine childhood immunisation services in the study area were selected purposively to ensure representation of the major immunisation service delivery points across the district. Within these catchment areas, wards and villages were randomly selected, and households were allocated proportionally according to population size. In the final stage, households with eligible children were selected using systematic sampling. Where more than one eligible child was present in a household, one child was selected using simple random sampling.

The required sample size was estimated using Cochran’s formula [15] for estimating a population proportion for an infinite population, n = (Z² × P (1 − P)) / e², assuming an immunisation coverage proportion (P = 0.5), a 95% confidence level (Z = 1.96), and a margin of error of 5%. To account for the multistage sampling design and potential non‑response, the sample size was adjusted using a design effect of 1.2. Ultimately, 573 caregiver–child pairs with complete data consented to participate and were included in the final analysis.

Data collection

Data were collected using structured questionnaires administered to caregivers. Information obtained included socio‑demographic characteristics, maternal factors, knowledge of immunisation, health service accessibility, and child vaccination status as recorded in the child health card.

Immunisation status was defined according to the Zimbabwe Expanded Programme on Immunisation (ZEPI) [5] schedule in effect during the study period. Children were receiving routine vaccinations from birth through the first year of life as follows: at birth, Bacille Calmette‑Guérin (BCG), oral polio vaccine zero dose (OPV0), and the Hepatitis B birth dose; at 6 weeks of age, the first doses of pentavalent vaccine (DTP‑HepB‑Hib1), oral polio vaccine (OPV1), pneumococcal conjugate vaccine (PCV1), and rotavirus vaccine (Rotavirus1); at 10 weeks, the second doses of pentavalent vaccine (DTP‑HepB‑Hib2), oral polio vaccine (OPV2), pneumococcal conjugate vaccine (PCV2), and rotavirus vaccine (Rotavirus2); at 14 weeks, the third doses of pentavalent vaccine (DTP‑HepB‑Hib3), oral polio vaccine (OPV3), and pneumococcal conjugate vaccine (PCV3); and at 9 months, the measles‑rubella (MR) vaccine [5, 6].

Children were classified as fully immunised if they had received all age‑appropriate vaccine doses recommended under the national schedule by 12 months of age, as verified from the child health card. Children were classified as partially immunised if they had received at least one vaccine dose but had missed one or more scheduled doses required to complete the national immunisation schedule by 12 months of age. Children who had not received any routine childhood vaccine were classified as not immunised.

The dependent variable was immunisation status, categorised as fully immunised, partially immunised, or not immunised; for binary logistic regression, children were classified as fully immunised (1) and incompletely immunised (partial or non‑immunised) (0). Independent variables comprised child factors (age, sex, and birth order); maternal factors (such as age, education, parity, and marital status); household characteristics (such as income, employment status, and family size); and health system‑related factors (including distance to the health facility, vaccine stockouts, waiting time, and availability of outreach services). Knowledge‑related variables were also assessed, focusing on caregivers’ awareness of immunisation schedules, VPDs, and the recommended timing of childhood vaccinations.

Data analysis

Data were entered into Microsoft Excel 2019 and analysed using Stata version 16 or R version 4.0. Descriptive statistics summarised participant characteristics and immunisation status. Associations between socio‑demographic, household, and caregiver factors and immunisation status were assessed using chi‑square tests and crude odds ratios (ORs) with 95% confidence intervals (CI). Statistical significance was set at p < 0.05. Variables significant at p < 0.2 in bivariate analyses were included in multivariate binary and multinomial logistic regression models. Model building followed a backward elimination approach, and model fit was evaluated using Hosmer–Lemeshow tests (binary logistic regression) and likelihood ratio tests (multinomial logistic regression). Multicollinearity was assessed using variance inflation factors (VIF < 5 considered acceptable) [16, 17].

Ethical considerations

Ethical approval for the study was sought from the Midlands State University Institutional Review Board, the Medical Research Council of Zimbabwe (MRCZ), and the Midlands Provincial and Gokwe South District Health Executive authorities. Written informed consent was obtained from all participating caregivers prior to data collection. Participant anonymity and confidentiality were maintained throughout the study. All study procedures were conducted in accordance with the ethical principles outlined in the Declaration of Helsinki [18].

Socio‑demographic characteristics

A total of 573 caregiver–child pairs were included in the analysis. Slightly more than half of the children were male (54.8%), while females accounted for 45.2%. Most children were born in health facilities (67.0%), while 33.0% were home births. Maternal education was generally low, with 35% of caregivers having no formal education, 40% primary education, and 25% secondary or higher education. The religious profile of caregivers reflected the district’s predominantly apostolic landscape: 11% belonged to the Marange apostolic sect, 44% to other apostolic groups, and the remaining 45% were affiliated with Pentecostal, Protestant, or Catholic churches. Additional demographic and household characteristics of the study sample are presented in Table 1.

Immunisation coverage

Overall, 356 children (62.1%) were fully immunised, 141 (24.6%) partially immunised, and 76 (13.3%) not immunised. Full immunisation was higher among males (57%) than females (43%), but the difference was not statistically significant (p = 0.12). Full, partial, and non‑immunisation by child sex and other characteristics are illustrated in Table 2.

Bivariate analysis of factors associated with immunisation status

Possession of a child health card strongly predicted full immunisation (OR = 3.2; 95% CI: 2.1–4.8; p < 0.001). Children of mothers with secondary or higher education were 2.8 times more likely to be fully immunised than children of mothers with no formal education (95% CI: 1.9–4.0; p < 0.001). Children from Marange apostolic households had lower uptake (OR = 0.42; 95% CI: 0.26–0.68; p < 0.001). Place of birth, birth order, knowledge of the immunisation schedule, exposure to immunisation education, knowledge of new vaccines, knowledge of VPDs, caregiver satisfaction with healthcare, negative perceptions, and worry about side effects were all significant predictors (all p < 0.05). Crude ORs are presented in Table 3.

Binary logistic regression

After adjusting for confounders, four variables independently predicted non‑immunisation. Children whose caregivers reported lower satisfaction with healthcare had 2.6 times higher odds of being non‑immunised (AOR = 2.6; 95% CI: 1.7–4.0; p < 0.001). Possession of a child health card remained protective (AOR = 3.5; 95% CI: 2.2–5.5; p < 0.001). Caregiver knowledge of new vaccines predicted full immunisation (AOR = 1.9; 95% CI: 1.2–3.1; p = 0.006). Marange apostolic affiliation was associated with lower immunisation odds (AOR = 0.44; 95% CI: 0.26–0.73; p = 0.002). Full regression results are shown in Table 4.

Multinomial logistic regression

Predictors of non‑immunisation (versus fully immunised) included caregiver dissatisfaction with healthcare (RRR = 2.8; 95% CI: 1.8–4.4; p < 0.001), home birth (RRR = 2.2; 95% CI: 1.4–3.5; p = 0.001), lack of a child health card (RRR = 4.1; 95% CI: 2.5–6.6; p < 0.001), and Marange apostolic affiliation (RRR = 0.39; 95% CI: 0.23–0.65; p < 0.001). Partial immunisation (versus fully immunised) was predicted by caregiver dissatisfaction with healthcare (RRR = 1.9; 95% CI: 1.2–3.0; p = 0.005), absence of a child health card (RRR = 2.8; 95% CI: 1.7–4.7; p < 0.001), and limited knowledge of newly introduced vaccines (RRR = 1.7; 95% CI: 1.1–2.6; p = 0.02). Notably, place of birth and religious affiliation were not significant for partial immunisation once other factors were adjusted for, suggesting different barriers influence partial versus complete non‑uptake. Taken together, the multinomial model demonstrates that predictors of partial and complete non‑immunisation are not identical, indicating distinct pathways leading to incomplete immunisation. These findings are summarised in Table 5.

Limitations

The study has some notable limitations. Its cross‑sectional design precludes causal inference, and reliance on caregiver recall for information not captured in child health cards may have introduced recall bias. Findings may not be generalisable to urban or more socio‑economically advantaged populations. Some variables, such as distance to health facilities, were self‑reported and may be prone to measurement error.

Recommendations

To enhance childhood immunisation coverage, health authorities should implement multifaceted interventions: strengthen health facility service quality, ensure consistent vaccine supply, engage religious communities to address socio‑cultural barriers, and promote caregiver health literacy through targeted education programmes. Special focus should be given to households with home births and children without health cards to reduce missed opportunities for vaccination.