Implementing WHO guidance on conducting and analysing vaccination coverage cluster surveys: Two examples from Nigeria

Navigating Nigeria's Health Landscape: Population Growth and Its Health Implications

This comprehensive analysis examines the multifaceted impacts of population growth on public health in Nigeria. Drawing parallels with Omran's epidemiological transition model (that focuses on the intricate means that patterns of health and illness are changing, as well as the relationships that exist between these patterns and the sociological, demographic, and economic factors that influence them) and referencing experiences from Chile and Ceylon. The study highlights a substantial rise in Nigeria's population causing a double burden of infectious and non-communicable diseases, leading to higher morbidity, and mortality rates, increased healthcare costs, decreased productivity, and health inequalities, posing significant challenges to the country's healthcare system. Furthermore, the correlation between low education levels and health outcomes underscores the importance of addressing systemic deficiencies in Nigeria's educational sector. The article emphasizes the urgent need for strategic interventions to mitigate the adverse effects of population growth on health. Recommendations include revitalizing primary healthcare centers, fostering public-private partnerships to enhance healthcare accessibility, leveraging technological advancements like telemedicine, and promoting initiatives to improve nutrition and environmental sustainability. Moreover, prioritizing education on reproductive health and family planning emerges as a crucial strategy to manage population growth sustainably. In conclusion, the article underscores the imperative for collaborative efforts across sectors to navigate Nigeria's evolving health landscape amidst increasing population growth. By implementing targeted policies and interventions, Nigeria can strive toward achieving universal health coverage, enhancing health outcomes, and ultimately raising the standard of living for its populace.

Missed opportunities for vaccination at point of care and their impact on coverage and urban-rural coverage inequity in the Gambia

INTRODUCTION

Identifying actionable targets is crucial to improve overall and equity in vaccination coverage, and in line with the global Immunization Agenda 2030. Therefore, this study seeks to assess the prevalence of missed opportunities for simultaneous vaccination (MOSVs) and their impact on vaccination coverage and urban-rural inequity in The Gambia.

METHODS

We used data of children aged 12-23 months from The Gambia 2019/2020 demographic and health survey (weighted n = 1355) with seen vaccination cards. We analyzed: the frequency of MOSVs; percentage point coverage reduction attributable to MOSVs for 18 vaccine doses and full basic vaccination; and MOSVs' contribution to urban-rural coverage inequity through Blinder-Oaxaca decomposition.

RESULTS

Sixty percent of children experienced MOSVs, in both urban and rural areas, but urban MOSVs were more seldom corrected (35.9 % vs 45.3 %). All eighteen vaccine doses assessed could have achieved between one to eleven percentage points higher coverage if MOSVs had been avoided, with full basic vaccination gaining even more. While MOSV correction did not impact overall urban-rural coverage inequity, it did exacerbate (explained coefficient = -0.1007; P = 0.002) inequities among children who experienced MOSVs, explaining 95 % of the observed difference.

CONCLUSION

Our study highlights the prevalence and negative impact of MOSVs on overall vaccination coverage. Although MOSVs did not contribute significantly to the total urban-rural inequity in coverage, they have detrimental effects on vaccination coverage and urban-rural inequity among children who had experienced MOSVs. Addressing MOSVs, can enhance coverage and reduce the risk of under-vaccination, aligning with global initiatives.

Timeliness of routine childhood vaccination among 12-35 months old children in The Gambia: Analysis of national immunisation survey data, 2019-2020

The Gambia's routine childhood vaccination programme is highly successful, however, many vaccinations are delayed, with potential implications for disease outbreaks. We adopted a multi-dimensional approach to determine the timeliness of vaccination (i.e., timely, early, delayed, and untimely interval vaccination). We utilised data for 3,248 children from The Gambia 2019-2020 Demographic and Health Survey. Nine tracer vaccines administered at birth and at two, three, four, and nine months of life were included. Timeliness was defined according to the recommended national vaccination windows and reported as both categorical and continuous variables. Routine coverage was high (above 90%), but also a high rate of untimely vaccination. First-dose pentavalent vaccine (PENTA1) and oral polio vaccine (OPV1) had the highest timely coverage that ranged from 71.8% (95% CI = 68.7-74.8%) to 74.4% (95% CI = 71.7-77.1%). Delayed vaccination was the commonest dimension of untimely vaccination and ranged from 17.5% (95% CI = 14.5-20.4%) to 91.1% (95% CI = 88.9-93.4%), with median delays ranging from 11 days (IQR = 5, 19.5 days) to 28 days (IQR = 11, 57 days) across all vaccines. The birth-dose of Hepatitis B vaccine had the highest delay and this was more common in the 24-35 months age group (91.1% [95% CI = 88.9-93.4%], median delays = 17 days [IQR = 10, 28 days]) compared to the 12-23 months age-group (84.9% [95% CI = 81.9-87.9%], median delays = 16 days [IQR = 9, 26 days]). Early vaccination was the least common and ranged from 4.9% (95% CI = 3.2-6.7%) to 10.7% (95% CI = 8.3-13.1%) for all vaccines. The Gambia's childhood immunization system requires urgent implementation of effective strategies to reduce untimely vaccination in order to optimize its quality, even though it already has impressive coverage rates.

Finagle's laws of information: lessons learnt evaluating a complex health intervention in Nigeria

Evaluations cannot support evidence-informed decision making if they do not provide the information needed by decision-makers. In this article, we reflect on our own difficulties evaluating the Geo-Referenced Infrastructure and Demographic Data for Development (GRID3) approach, an intervention that provides high-resolution demographic and geographical information to support health service delivery. GRID3 was implemented in Nigeria's northern states to support polio (2012-2019) and measles immunisation campaigns (2017-2018). Generalising from our experience we argue that Finagle's four laws of information capture a particular set of challenges when evaluating complex interventions: the weak causal claims derived from quasi-experimental studies and secondary analyses of existing data (the information we have is not the data we want); the limited external validity of counterfactual impact evaluations (the information we want is not the information we need); the absence of reliable monitoring data on implementation processes (the information we need is not what we can obtain) and the overly broad scope of evaluations attempting to generate both proof of concept and evidence for upscaling (the information we can obtain costs more than we want to pay). Evaluating complex interventions requires a careful selection of methods, thorough analyses and balanced judgements. Funders, evaluators and implementers share a joint responsibility for their success.

Added value of the measles-rubella supplementary immunization activity in reaching unvaccinated and under-vaccinated children, a cross-sectional study in five Indian districts, 2018-20

INTRODUCTION

Supplementary immunization activities (SIAs) aim to interrupt measles transmission by reaching susceptible children, including children who have not received the recommended two routine doses of MCV before the SIA. However, both strategies may miss the same children if vaccine doses are highly correlated. How well SIAs reach children missed by routine immunization is a key metric in assessing the added value of SIAs.

METHODS

Children aged 9 months to younger than 5 years were enrolled in cross-sectional household serosurveys conducted in five districts in India following the 2017-2019 measles-rubella (MR) SIA. History of measles containing vaccine (MCV) through routine services or SIA was obtained from documents and verbal recall. Receipt of a first or second MCV dose during the SIA was categorized as "added value" of the SIA in reaching un- and under-vaccinated children.

RESULTS

A total of 1,675 children were enrolled in these post-SIA surveys. The percentage of children receiving a 1st or 2nd dose through the SIA ranged from 12.8% in Thiruvananthapuram District to 48.6% in Dibrugarh District. Although the number of zero-dose children prior to the SIA was small in most sites, the proportion reached by the SIA ranged from 45.8% in Thiruvananthapuram District to 94.9% in Dibrugarh District. Fewer than 7% of children remained measles zero-dose after the MR SIA (range: 1.1-6.4%) compared to up to 28% before the SIA (range: 7.3-28.1%).

DISCUSSION

We demonstrated the MR SIA provided considerable added value in terms of measles vaccination coverage, although there was variability across districts due to differences in routine and SIA coverage, and which children were reached by the SIA. Metrics evaluating the added value of an SIA can help to inform the design of vaccination strategies to better reach zero-dose or undervaccinated children.

Multilevel analysis of predictors of multiple indicators of childhood vaccination in Nigeria

Background

Substantial inequalities exist in childhood vaccination coverage levels. To increase vaccine uptake, factors that predict vaccination coverage in children should be identified and addressed.

Methods

Using data from the 2018 Nigeria Demographic and Health Survey and geospatial data sets, we fitted Bayesian multilevel binomial and multinomial logistic regression models to analyse independent predictors of three vaccination outcomes: receipt of the first dose of Pentavalent vaccine (containing diphtheria-tetanus-pertussis, Hemophilus influenzae type B and Hepatitis B vaccines) (PENTA1) (n = 6059) and receipt of the third dose having received the first (PENTA3/1) (n = 3937) in children aged 12–23 months, and receipt of measles vaccine (MV) (n = 11839) among children aged 12–35 months.

Results

Factors associated with vaccination were broadly similar for documented versus recall evidence of vaccination. Based on any evidence of vaccination, we found that health card/document ownership, receipt of vitamin A and maternal educational level were significantly associated with each outcome. Although the coverage of each vaccine dose was higher in urban than rural areas, urban residence was not significant in multivariable analyses that included travel time. Indicators relating to socio-economic status, as well as ethnic group, skilled birth attendance, lower travel time to the nearest health facility and problems seeking health care were significantly associated with both PENTA1 and MV. Maternal religion was related to PENTA1 and PENTA3/1 and maternal age related to MV and PENTA3/1; other significant variables were associated with one outcome each. Substantial residual community level variances in different strata were observed in the fitted models for each outcome.

Conclusion

Our analysis has highlighted socio-demographic and health care access factors that affect not only beginning but completing the vaccination series in Nigeria. Other factors not measured by the DHS such as health service quality and community attitudes should also be investigated and addressed to tackle inequities in coverage.

Who gets vaccinated in a measles-rubella campaign in Nepal?: results from a post-campaign coverage survey

BACKGROUND

Following the 2015 earthquake, a measles-rubella (MR) supplementary immunization activity (SIA), in four phases, was implemented in Nepal in 2015-2016. A post-campaign coverage survey (PCCS) was then conducted in 2017 to assess SIA performance and explore factors that were associated with vaccine uptake.

METHODS

A household survey using stratified multi-stage probability sampling was conducted to assess coverage for a MR dose in the 2015-2016 SIA in Nepal. Logistic regression was then used to identify factors related to vaccine uptake.

RESULTS

Eleven thousand two hundred fifty-three households, with 4870 eligible children provided information on vaccination during the 2015-2016 MR SIA. Overall coverage of measles-rubella vaccine was 84.7% (95% CI: 82.0-87.0), but varied between 77.5% (95% CI: 72.0, 82.2) in phase-3, of 21 districts vaccinated in Feb-Mar 2016, to 97.7% (CI: 95.4, 98.9) in phase-4, of the last seven mountainous districts vaccinated in Mar-Apr 2016. Coverage in rural areas was higher at 85.6% (CI: 81.9, 88.8) than in urban areas at 79.0% (CI: 75.5, 82.1). Of the 4223 children whose caregivers knew about the SIA, 96.5% received the MR dose and of the 647 children whose caregivers had not heard about the campaign, only 1.8% received the MR dose.

CONCLUSIONS

The coverage in the 2015-2016 MR SIA in Nepal varied by geographical region with rural areas achieving higher coverage than urban areas. The single most important predictor of vaccination was the caregiver being informed in advance about the vaccination campaign. Enhanced efforts on social mobilization for vaccination have been used in Nepal since this survey, notably for the most recent 2020 MR campaign.

Using Household Surveys to Assess Missed Opportunities for Simultaneous Vaccination: Longitudinal Examples from Colombia and Nigeria

One important strategy to increase vaccination coverage is to minimize missed opportunities for vaccination. Missed opportunities for simultaneous vaccination (MOSV) occur when a child receives one or more vaccines but not all those for which they are eligible at a given visit. Household surveys that record children’s vaccination dates can be used to quantify occurrence of MOSVs and their impact on achievable vaccination coverage. We recently automated some MOSV analyses in the World Health Organization’s freely available software: Vaccination Coverage Quality Indicators (VCQI) making it straightforward to study MOSVs for any Demographic & Health Survey (DHS), Multi-Indicator Cluster Survey (MICS), or Expanded Programme on Immunization (EPI) survey. This paper uses VCQI to analyze MOSVs for basic vaccine doses among children aged 12–23 months in four rounds of DHS in Colombia (1995, 2000, 2005, and 2010) and five rounds of DHS in Nigeria (1999, 2003, 2008, 2013, and 2018). Outcomes include percent of vaccination visits MOSVs occurred, percent of children who experienced MOSVs, percent of MOSVs that remained uncorrected (that is, the missed vaccine had still not been received at the time of the survey), and the distribution of time-to-correction for children who received the MOSV dose at a later visit.