Coverage and predictors of full measles-rubella immunization among children aged 24–59 months in Northern Ghana: a post measles outbreak assessment

Abstract

Introduction

Vaccination plays a critical role in ensuring the health, survival, and well-being of children worldwide. It is one of the most cost-effective and scientifically proven public health interventions that protect children from severe and life-threatening diseases. Despite efforts to improve measles vaccination coverage in the five Northern regions of Ghana, less than 70% complete vaccination coverage leaves these areas vulnerable to outbreaks. To fill this gap, our study explores the predictors of complete measles immunization coverage among children aged 24–59 months in Northern Ghana.

Methods

A community-based cross-sectional study was conducted from June to September 2023. Data was collected from caregivers of children aged 24–59 months. A sample size of 636 children with a multistage sampling technique was used. We collected data from the caregivers using a semi-structured questionnaire and a data abstraction tool. Logistic regression was used to assess the factors associated with measles vaccine uptake at a 5% significance level.

Results

Among the 617 children, 61.1% (0.57–0.65) were fully vaccinated against measles. The first dose of the measles-rubella vaccine was received by 87.7% (95% CI: 0.84–0.90) of the children. After adjusting for potential confounders, regression models showed that the awareness (aOR = 2.91, 95% CI:1.35–6.25), high knowledge level (aOR = 8.27, 95% CI:3.02–22.71), ANC (aOR = 2.48, 95% CI:1.11–5.52), side effects (aOR = 0.04, 95% CI:0.02–0.08) and receiving other childhood vaccines (aOR = 3.27, 95%CI:1.80–5.94) were significantly associated with the uptake of measles-rubella vaccines in Northern Ghana.

Conclusion

The uptake of the second dose of the measles-rubella vaccine in Northern Ghana was below the recommended 95% by the WHO. Awareness of the vaccine, knowledge level, ANC attendance, receiving other vaccines, and perceived side effects were the main predictors of measles vaccine uptake in the region. Ghana Health Service should intensify sensitization and awareness creation at the community level.

Introduction

Measles remains a significant global public health challenge despite the availability of a safe and effective vaccine [1]. It is one of the most contagious infectious diseases, with an estimated basic reproduction number (R0) ranging between 12 and 18. In 2023 alone, there were approximately 9 million measles cases and 128,000 deaths worldwide, the majority occurring in low- and middle-income countries (LMICs) [1]. Despite the availability of safe and effective vaccines, measles remains a leading cause of death among young children globally [2]. Unvaccinated young children are at the highest risk of measles and its severe complications, including fatality. Furthermore, any individual lacking immunity, either due to lack of vaccination or failure to develop immunity post-vaccination, is susceptible to infection [3].

Immunization is one of the most successful public health interventions in the prevention and control of infectious disease outbreaks [4, 5]. Timely vaccination during childhood plays a pivotal role in establishing immunity before exposure to potentially life-threatening diseases [6]. Vaccines have been instrumental in the prevention of measles which threatened the lives of children before the development of vaccines [7].

In Ghana, immunization is a critical component of the healthcare services provided free of charge to children under 23 months of age. The Expanded Program on Immunization (EPI) in Ghana’s routine schedule recommends that infants should be vaccinated with one dose of the measles and rubella (MR) vaccine at 9 months of age and a second dose at 18 months [8, 9]. Therefore, children are expected to be fully immunized against measles by 18 months. According to the 2022 Ghana Demographic Health Survey, 72.5% of children aged 24–35 months received 2 doses of measles-rubella vaccine nationwide. Disaggregating by region, Northern, Savanna, and Upper East regions had 56.5%, 66.4%, and 79.0% measles 2 vaccination coverage respectively [10].

Between 2022 and 2023, the five Northern regions reported 3460 suspected cases of measles with 111 confirmed positive. Despite the reported low measles immunization coverage rate coupled with the more than 10 sporadic measles outbreaks between 2022 and 2023, there is limited literature on the factors that influence the uptake of measles vaccines among children aged 24–59 months. This study, therefore, aimed to assess the predictors of complete measles immunization coverage in this age group in Northern Ghana, following a measles outbreak that resulted in the deaths of five children. The findings are expected to provide valuable insights to policymakers on new strategies to enhance measles vaccine uptake and mitigate the burden of measles in the region.

Methods

Study design and setting

A community-based cross-sectional study was conducted from June to September 2023 to assess the factors associated with the uptake of measles-rubella vaccines among children 24–59 months in COVID Northern Ghana. We collected data from the caregivers of children aged 24–59 months using a semi-structured questionnaire and a data extraction tool. The data extraction tool is a structured instrument designed to collect relevant information on measles immunization coverage from the maternal and child health records booklet. It includes sections on demographic characteristics, vaccination history (verified through child health records and caregiver recall). The tool ensures standardized data collection, facilitating accurate assessment of immunization coverage and identifying gaps in measles vaccination within the study population. r. Data on measles-rubella vaccine uptake, dropout rates, sociodemographic characteristics, and individual-level factors were collected. The northern zone of Ghana is located in the Northern part of the country and comprises five regions: The Northern region, Upper West region, Upper East region, Savanna, and North East region. The zone shares boundaries with Burkina Faso to the North, Middle Belt of Ghana to the South, Togo to the East, and Ivory Coast to the West. The zone has an estimated 1,123,526 children under five years [11]. The zone has health facilities ranging from community-based health planning and service zones to district hospitals that render immunization services to the populace.

Study population and eligibility

The study included all mothers with a live birth between 24 and 59 months in Northern Ghana. The exclusion criteria were caregivers or parents in whose children’s measles-rubella vaccines were contraindicated.

Sample size estimation and sampling procedure

The sample size of 636 was calculated using the formula n = [DEFF × Z² × p (1-p)]/e². Where n is the sample size, Z: the Z-score at a 95% confidence interval which is 1.96, DEFF: the design effect of 2 (assuming an intra-cluster correlation of 1/6), P (73%) coverage, and e (5%) is the margin of error allowed and 5% non-response rate. A multistage cluster sampling approach was adopted to sample caregivers for the study. The existing geographical districts in the Northern zone were considered as clusters. Out of 49 clusters in the zone, 20 clusters were selected using a simple random approach in Microsoft Excel. In each of the selected clusters, 2 communities were selected: an urban and a rural community. The number of households to be sampled from each community was proportionally allocated based on the population of children aged 24–59 months. Simple random sampling was used to select the households by spinning a pen at the geographic centre of the cluster; the same procedure was used to select the subsequent household with an eligible child for the study. If the selected household did not have an eligible child, the same procedure was repeated for the direction of the next household, following the principle of ‘the nearest household with an eligible child’. The youngest eligible child was selected for the household with more than one eligible child for coverage.

Data collection

Data was collected using a semi-structured questionnaire and a data abstraction tool. The semi-structured questionnaire and the data abstraction tool were adapted from published tools in previous studies conducted in Ghana and Ethiopia [12, 13]. The semi-structured questionnaire collected data on the sex of the child, caregivers’ sex, educational level, income, county of residence, religion, marital status, availability of vaccines, attitude of health workers, availability of health facilities, and the vaccines taken. The questionnaire was prepared in English and translated into Frafra, Gonja, Kasena, Dagbani, Nanumba, Mamprusi, and Konkomba languages for administration. The data abstraction tool elicited information on the measles-rubella vaccine uptake, the number of doses, and the date of vaccine uptake from the maternal and child health record books. Confirmation of vaccination status was through both records review and caregiver recall. COVID-19 safety protocolsmeant to protect the research assistants and study participants were observed.

Study outcome

Fully vaccinated - A child between 24 and 59 months old who received at least two doses of the measles-rubella vaccine.

Partially vaccinated - a child who missed a dose of the measles-rubella vaccine.

Unvaccinated- a child who did not receive any dose of the measles-rubella vaccine.

Explanatory variables and selection criteria

The explanatory variables for this study were selected based on their potential influence on measles immunization coverage, as identified in existing literature and public health frameworks. These variables were categorized into socio-demographic, healthcare access, and immunization-related factors and assessed using structured questionnaires, child health records reviews, and caregiver interviews.

Socio-Demographic Variables:

• Child’s age (months)– Categorized into appropriate age groups for analysis.

• Sex of the child– Recorded as male or female.

• Maternal age (years)– Grouped into age brackets (e.g., < 20, 20–29, 30–39, ≥ 40).

• Maternal education level– Classified as no formal education, primary, secondary, or higher education.

• Residence type– Urban vs. rural classification.

Healthcare Access Factors:

• Distance to the nearest health facility– Categorized as < 5 km, 5–10 km, or > 10 km.

• Antenatal care (ANC) attendance– Measured as the number of ANC visits during pregnancy.

• Place of delivery– Recorded as health facility or home delivery.

• Postnatal care utilization– Whether the child received postnatal care within six weeks of birth.

• Access to immunization services– Whether caregivers reported challenges in reaching immunization services (e.g., transport costs, availability of vaccines).

Immunization-Related Factors:

• Possession of a child health record (vaccination card)– Yes/No.

• Timeliness of measles vaccination– Assessed by comparing recorded dates on health cards with the national immunization schedule.

• Number of measles-rubella vaccine doses received– Verified from health records and categorized as none, one, or two doses.

• Missed vaccination opportunities– Defined as eligible children who had contact with healthcare services but did not receive measles vaccination.

• Caregiver knowledge and perception of vaccination– Assessed through structured questions on vaccine benefits, risks, and hesitancy.

Assessment of explanatory variables

The variables were assessed through multiple data sources, including:

• Semi-structured questionnaires administered to caregivers to obtain socio-demographic information and healthcare access data.

• Child health records (vaccination cards) to verify immunization history and timeliness of vaccine doses.

The selection of these explanatory variables was guided by previous research on vaccine coverage determinants, the WHO’s immunization framework, and factors influencing vaccine uptake in LMICs. These variables were analyzed to determine their association with measles immunization coverage among children aged 24–59 months in the study area.

Data management and analysis

Microsoft Excel files of the data collected on the Kobo collect toolbox were obtained. Data was cleaned and imported into STATA for analysis. Measles Vaccination Status was categorized into Fully vaccinated (Received two doses of the measles-rubella vaccine) and Not fully vaccinated (Received one or no dose)– (0). All categorical explanatory variables were categorized and coded for analysis.

Categorical variables such as the sex of the child, caregiver’s marital status, educational level, income, residence, religion, and marital status were summarized into frequencies and proportions.

Parametric continuous variables such as the age of the caregiver were summarized using means and standard deviations while non-parametric continuous variable such as the age of the child was summarized into median and interquartile ranges. Logistic regression was used to assess the factors associated with measles-rueblla vaccine uptake at a 5% significance level. Variables for the multivariate logistic regression were selected using a forward stepwise approach. The multivariate logistic regression model controlled for potential confounders to ensure adjusted associations between the explanatory variables and measles immunization status. The following key variables were adjusted for in the final model: child’s age, maternal education level, household socioeconomic status, residence type (urban vs. rural), distance to health facility, antenatal care attendance, possession of a child health record and missed vaccination opportunities.

Results

Child and caregiver’s background characteristics

A total of 617 out of the 636 participants responded. Of the 617 caregivers of the children studied, 55.9% (345) were from rural settings. The average age of the caregivers was 29.29 ± 6.10 years while the average age of the children was 32 months (IQR: 28–42). Majority 53.7% (331/617) of the caregivers had no formal education (Table 1).

Table 1 Child and caregiver’s background characteristics

Individual-level characteristics of caregivers

Of the 617 caregivers, more than two-thirds (73.7%, 455) had attended antenatal care clinics during pregnancy with the child of interest, and 82.7% (510) delivered their babies in a health facility. Approximately 80% (490) of the caregivers were aware of the measles-rubella vaccine, but only 21.2% (131) had a high knowledge of the number of doses, the schedule, and the importance of the vaccine (Table 2).

Table 2 Individual-level characteristics of caregivers

Measles-rubella vaccination coverage among children aged 24–59 months

Of the 617 children studied, 61.10% (0.57–0.65) were fully vaccinated (received both MR1 and MR2) while MR1 was received by 87.7% (0.84–0.90) (Table 3).

Table 3 Update of measles-rubella vaccination among children aged 24–59 months

Urban-rural stratification of Measles-Rubella vaccination coverage

Most, 84.3% (0.80–0.88) of the children from rural settings were fully vaccinated compared to the children from urban settings 31.6% (0.26–0.38) (Table 4).

Table 4 Stratification of measles-rubella vaccination coverage by place of residence

Factors associated with Measles-Rubella vaccination coverage

Children of caregivers who were aware of the measles-rubella vaccine had more than twice the odds of receiving two doses compared to children of caregivers who were not aware (aOR = 2.91, 95% CI:1.35–6.25). Additionally, children who had received all other childhood vaccines had three times the odds of receiving two doses of the measles-rubella vaccine compared to those who were only partially vaccinated with other childhood vaccines (aOR = 3.27, 95% CI:1.80–5.94) (Table 5).

Table 5 Factors associated with the MR vaccine uptake

Discussions

[1, 4]In Ghana, two doses of the measles-rubella vaccine are administered to ensure high levels of immunity among children and to prevent outbreaks. The first dose, administered at 9 months, may not provide full protection for all children due to factors such as the presence of maternal antibodies or weakened immune responses. Therefore, a second dose at 18 months serves as a critical catch-up to immunize those who did not respond to the first dose. This approach aligns with World Health Organization recommendations for high-burden settings and helps achieve the ≥ 95% population immunity needed for effective measles control and eventual elimination. Our study revealed that more than 80% of the children studied received one dose of the measles-rubella vaccine while about 61% received both doses of the vaccine. This implies that about 61% of the children aged 24–59 months studied were immunized against the measles virus in Northern Ghana. With more than 30% of children aged 24–59 months unprotected from measles in the region, the risk of measles outbreaks is high, this could explain the numerous measles outbreaks recorded in the region between 2022 and 2023. To curb these measles outbreaks, it is vital to implement measures aimed at increasing the measles-rubella vaccination coverage in the region to the 95% herd immunity coverage target recommended by the World Health Organization [14]. The 61% coverage level recorded in this study is higher than coverages recorded by studies conducted in other countries including Cherangany Sub County of Kenya (56.2%) [15], Nigeria (18%) [16], sub-Saharan Africa (41%) [17], Upper East Region of Ghana (18.2%) [5] and North Shoa Zone, Central Ethiopia (42.5%) [14]. However, studies conducted in Bangladesh (88%) [18] and Armenia (79.6%) [19] reported higher coverage levels. The low full measles immunization coverage recorded in our study compared to the coverage in Bangladesh and Armenia could be attributed to the number of doses required for full measles immunity and the difference in the measles immunization schedule. A single dose of measles vaccine is implemented in Bangladesh compared to Ghana which is two doses. Also, in Armenia, children aged six are still eligible for the second dose of the measles vaccine which is different from the 18 months through to 59 months eligibility in Ghana.

The study revealed higher vaccination coverage in rural areas of Ghana compared to children from urban communities. The notably lower measles-rubella vaccination coverage among urban children compared to their rural counterparts may reflect differences in health-seeking behavior, population mobility, and health service utilization patterns. In urban areas, caregivers may face challenges such as competing work schedules, limited awareness of immunization schedules, or perceived lower risk of disease, leading to missed opportunities for vaccination. Additionally, rapid urbanization and the presence of underserved populations in informal settlements may hinder access to routine immunization services. These factors may collectively contribute to the observed disparity and warrant targeted urban immunization strategies.

With children under 5 years of age, the awareness and knowledge of their caregivers on the importance of immunization is a significant factor influencing the uptake of vaccines globally. Our study revealed a significant association between the awareness and knowledge of caregivers on the importance of receiving both doses of the measles-rubella vaccine and being fully immunized against measles. Caregivers who were aware or had high knowledge about the recommended measles-rubella vaccine had increased odds of getting their children fully immunized compared to caregivers who had little or no knowledge of the number of recommended vaccine doses. To increase full measles immunization coverage, it is important to get caregivers informed and educated on the importance of receiving two measles-rubella vaccine doses and not just one. This can be achieved through intensifying education on measles-rubella vaccines during antenatal and postnatal health schedules in all health facilities in the region. Our findings are corroborated by the results of a similar study on the predictors for low coverage of uptake of a second dose of measles vaccine among children in sub-Saharan Africa, where caregiver’s knowledge of the importance of the second dose of measles was associated with increased odds of receiving the dose [17]. Also, caregivers’ awareness of the number of measles-rubella vaccines recommended was associated with full measles immunization among the children in Cherangany Sub County Kenya [15].

Antenatal care attendance was another factor found to be associated with full measles immunization coverage among the children studied. In most antenatal care facilities in Ghana, health talks are organized where pregnant women are educated on maternal and child health topics including immunization schedules. These health talks get the women informed on the recommended measles-rubella vaccines thereby increasing the chance of getting their children fully immunized after birth. The findings of this study are consistent with the results of a secondary data analysis based on recent Demographic and Health Surveys (DHS) data from eight Sub-Saharan African countries where ANC attendance was associated with increased odds of being immunized against measles [20]. Also, similar studies in Alego-Usonga Sub-County, Siaya County, Kenya [21], and Nigeria [16] reported a positive association between ANC attendance and measles immunization coverage among the children studied.

Furthermore, receiving other recommended childhood vaccines was another factor found to influence measles-rubella vaccine coverage among the children studied. Children who had received all other recommended vaccines had increased odds of being fully immunized against measles compared to children who had missed other childhood vaccines. This is consistent with the findings of a study aimed to estimate the measles vaccine coverage and factors associated with its uptake in Cherangany Sub County Kenya where child vaccination status for other scheduled vaccines was positively associated with being fully immunized against measles [15].

Lastly, this study’s findings shows that side effects after vaccination was associated with reduced odds of being vaccinated against measles. Vaccines are given to seemingly healthy children, and hence side effects can deter caregivers from giving their wards vaccines once the vaccine is seen to be the cause of their illness rather than a protection. Education on side effects vis-à-vis the benefits of vaccination should be intensified during immunization talks in antenatal and postnatal clinics across the country.

This study was limited by recall bias. Caregivers who could not provide maternal and child health record books containing their children’s immunization history responded to vaccine coverage questions based on recall. To address this limitation, research assistants were trained on how to use past events and significant dates to facilitate recall among caregivers.

Strengths and limitations of the study

Strengths

Use of Population-Based Data: The study utilizes data from a representative sample, ensuring that the findings reflect the broader population and can be used to inform policy decisions. Also, by adjusting for potential confounders in the logistic regression model, the study provides a more robust assessment of factors influencing measles vaccination coverage. The study also highlights unique urban-rural disparities in vaccination coverage, which can guide targeted interventions in different geographic areas. Inclusion of both socioeconomic and healthcare factors including maternal education, healthcare access, and vaccine hesitancy, the study provides a comprehensive understanding of barriers to vaccination.

Limitations

The study relied on caregivers’ recall of vaccination history, to supplement data abstracted from vaccination records. This may lead to inaccuracies due to recall bias by the caregivers. Future studies should consider using solely vaccination records or electronic health data to improve accuracy. Limited Assessment of Vaccine Hesitancy Determinants: While vaccine hesitancy is discussed, the study does not fully explore specific beliefs or misinformation that influence caregivers’ decisions. Future qualitative research could provide deeper insights.

Conclusion

The uptake of the second dose of the measles-rubella vaccine in Northern Ghana was below the recommended 95% by the WHO. Awareness of the vaccine, knowledge level, ANC attendance, receiving other vaccines, and perceived side effects were the main predictors of measles-rubella vaccine uptake in the region. Eligible partially vaccinated children identified during the study were linked to an arranged health team for immunization.