Inequalities In Vaccination Coverage Research Articles

Geospatial Analyses of Recent Household Surveys to Assess Changes in the Distribution of Zero-Dose Children and Their Associated Factors before and during the COVID-19 Pandemic in Nigeria.

The persistence of geographic inequities in vaccination coverage often evidences the presence of zero-dose and missed communities and their vulnerabilities to vaccine-preventable diseases. These inequities were exacerbated in many places during the coronavirus disease 2019 (COVID-19) pandemic, due to severe disruptions to vaccination services. Understanding changes in zero-dose prevalence and its associated risk factors in the context of the COVID-19 pandemic is, therefore, critical to designing effective strategies to reach vulnerable populations. Using data from nationally representative household surveys conducted before the COVID-19 pandemic, in 2018, and during the pandemic, in 2021, in Nigeria, we fitted Bayesian geostatistical models to map the distribution of three vaccination coverage indicators: receipt of the first dose of diphtheria-tetanus-pertussis-containing vaccine (DTP1), the first dose of measles-containing vaccine (MCV1), and any of the four basic vaccines (bacilli Calmette-Guerin (BCG), oral polio vaccine (OPV0), DTP1, and MCV1), and the corresponding zero-dose estimates independently at a 1 × 1 km resolution and the district level during both time periods. We also explored changes in the factors associated with non-vaccination at the national and regional levels using multilevel logistic regression models. Our results revealed no increases in zero-dose prevalence due to the pandemic at the national level, although considerable increases were observed in a few districts. We found substantial subnational heterogeneities in vaccination coverage and zero-dose prevalence both before and during the pandemic, showing broadly similar patterns in both time periods. Areas with relatively higher zero-dose prevalence occurred mostly in the north and a few places in the south in both time periods. We also found consistent areas of low coverage and high zero-dose prevalence using all three zero-dose indicators, revealing the areas in greatest need. At the national level, risk factors related to socioeconomic/demographic status (e.g., maternal education), maternal access to and utilization of health services, and remoteness were strongly associated with the odds of being zero dose in both time periods, while those related to communication were mostly relevant before the pandemic. These associations were also supported at the regional level, but we additionally identified risk factors specific to zero-dose children in each region; for example, communication and cross-border migration in the northwest. Our findings can help guide tailored strategies to reduce zero-dose prevalence and boost coverage levels in Nigeria.

Performance of predictive algorithms in estimating the risk of being a zero-dose child in India, Mali and Nigeria

IntroductionMany children in low-income and middle-income countries fail to receive any routine vaccinations. There is little evidence on how to effectively and efficiently identify and target such ‘zero-dose’ (ZD) children.MethodsWe...

Immunisation status of children receiving care and support in Wales: a national data linkage study.

In the UK, a robust childhood immunisation programme ensures children are offered protection against serious infections; identifying inequalities in vaccination coverage is essential. This is one of the first data linkage studies to examine coverage of primary, as well as pre-school booster and second dose of MMR vaccines, in children receiving support from social care services across Wales. By accessing records held within the Secure Anonymised Information Linkage (SAIL) Databank, vaccination status of children receiving social care and support between April 2016 and March 2021 (n = 24,540) was ascertained. This was achieved through linkage of the Children Receiving Care and Support (CRCS) Census and National Community Child Health Database which holds vaccination records for all children in Wales registered for NHS care. This sample was split into three groups - those children who had never been recorded on the Child Protection Register (CPR) or as 'Looked After' but in CRCS (n = 12,480), children ever on the CPR (n = 6,225) and those ever recorded as 'Looked After' but who were never on the CPR (n = 5,840). The comparison group of children and young people (CYP) never receiving welfare support consisted of 624,905 children. Children receiving care or support were more likely to be up-to-date with all six vaccines (no recorded vaccines: 0.6-6.3%) compared to children in the comparison group (no recorded vaccines: 3-10.3%). However, of those who were vaccinated, they were less likely to be vaccinated in a timely manner; both early (5.2% vs. 22.2%; margin of error [ME] = 0.52, 95% CI [confidence interval] = -0.18 - -0.17, p < 0.001) and delayed vaccinations were more common (62.7% vs. 71.3%; ME = 0.58, 95% CI = 0.08-0.09, p < 0.001). Validation of the CRCS immunisation flag showed moderate levels of accuracy. Around 70% of immunisation flags were correct across all three groups. Findings suggest a positive association between receiving services under a care and support plan and being up-to-date with immunisations; children receiving support under a care and support plan were more likely to have experienced early or late vaccinations, demonstrating that there is still more inter-disciplinary co-ordination and planning needed to improve these outcomes. Thus, identifying inequalities in vaccination coverage is essential to target interventions and to prioritise geographic areas for catch-up.

Adapting SARS-CoV-2 vaccination delivery in England to population needs: a thematic analysis of providers and commissioner’s perceptions

BackgroundA national SARS-CoV-2 vaccination programme was implemented in England from 8th December 2020, adopting a series of local level service delivery models to maximise rollout. The evidence base informing service design programme at inception was limited. We examined the real-world implementation of the programme through an assessment of sub-national providers’ and commissioners’ perspectives on the service delivery models used, to strengthen evidence on the acceptability, effectiveness and efficiency of the service delivery approaches used for SARS-CoV-2 vaccination in England or elsewhere.MethodsQualitative, cross-sectional analysis based on semi-structured interviews conducted with 87 stakeholders working in SARS-CoV-2 vaccination delivery across four regions in England. Localities were selected according to geography and population socio-economic status. Participants were purposively sampled from health service providers, commissioners and other relevant bodies. Interviews were conducted between February and October 2021, and transcripts were thematically analysed using inductive and deductive approaches.ResultsVarious service delivery models were implemented over the course of the programme, beginning with hospital hubs and mass vaccination sites, before expanding to incorporate primary care-led services, mobile and other outreach services. Each had advantages and drawbacks but primary care-led models, and to some extent pharmacies, were perceived to offer a better combination of efficiency and community reach for equitable delivery. Common factors for success included availability of a motivated workforce, predictability in vaccine supply chains and strong community engagement. However, interviewees noted a lack of coordination between service providers in the vaccination programme, linked to differing financial incentives and fragmentated information systems, among other factors.ConclusionA range of delivery models are needed to enable vaccine rollout at pace and scale, and to mitigate effects on routine care provision. However, primary care-led services offer a tried-and-trusted framework for vaccine delivery at scale and pace and should be central to planning for future pandemic responses. Mass vaccination sites can offer delivery at scale but may exacerbate inequalities in vaccination coverage and are unlikely to offer value for money. Policymakers in England should prioritise measures to improve collaboration between service providers, including better alignment of IT systems.

Socioeconomic and residence‐based related inequality in childhood vaccination in Sub‐Saharan Africa: Evidence from Benin

Childhood vaccination remains a cost-effective strategy that has expedited the control and elimination of numerous diseases. Although coverage of new vaccines in low- and middle-income countries increased exponentially in the last two decades, progress on expanding routine vaccination services to reach all children remains low, and coverage levels in many countries remains inadequate. This study aimed to examine the pattern of wealth and residence-based related inequality in vaccination coverage through an equity lens. We used data from the 2017-2018 Benin Demographic and Health Survey. Statistical and econometrics modeling were used to investigate factors associated with childhood vaccination. The Wagstaff decomposition analysis was used to disentangle the concentration index. A total of 1993 children were included, with 17% in the wealthiest quintile and 63% were living in rural areas. Findings showed that wealth is positively and significantly associated with vaccination coverage, particularly, for middle-wealth households. A secondary or higher education level of women and partners increased the odds of vaccination compared to no education (p < 0.05). Women with more antenatal care visits, with multiple births, attending postnatal care and delivery in a health facility had increased vaccination coverage (p < 0.01). Inequalities in vaccination coverage are more prominent in rural areas; and are explained by wealth, education, and antenatal care visits. Inequality in child vaccination varies according to socioeconomic and sociodemographic characteristics and is of interest to health policy. To mitigate inequalities in child vaccination coverage, policymakers should strengthen the availability and accessibility of vaccination and implement educational programs dedicated to vulnerable groups in rural areas.

Multivariate assessment of vaccine equity in Nigeria: A VERSE tool case study using demographic and health survey 2018

Nigeria experiences wide heterogeneity in vaccination rates by vaccine and region. However, inequities in vaccination status extend beyond just geographic covariates. Traditionally, inequity is represented by a single metric pertaining to socioeconomic status. A growing body of literature suggests that this view is limiting, and a multi-factor approach is necessary to comprehensively evaluate relative disadvantage between individuals.The Vaccine Economics Research for Sustainability and Equity (VERSE) tool produces a composite equity metric, which accounts for multiple factors influencing inequity in vaccination coverage. We apply the VERSE tool to Nigeria’s 2018 Demographic and Health Survey (DHS) to cross-sectionally evaluate equity in vaccination status for national immunization program (NIP) vaccines over the following contributing covariates: age of child, sex of child, maternal education level, socioeconomic status, health insurance status, state of residence, and urban or rural designation. We also assess equity for zero-dose, fully immunized for age, and completion of NIP.Results show that socioeconomic status contributes substantially to variation vaccination coverage, but it is not the most substantial factor. For all vaccination statuses, except for NIP completion, maternal education level is the greatest contributor towards a child’s immunization status among model variables. We highlight the outputs for zero-dose, fully immunized at infancy, MCV1 and PENTA1. The percentage point gap in vaccination status between the top and bottom quintiles of disadvantage, as ranked by the composite indicator is 31.1 (29.5–32.7) for zero-dose status, 53.1 (51.3–54.9) for full immunization status, 48.9 (46.9–50.9) for MCV1, and 67.6 (66.0–69.2) for PENTA1. Though concentration indices indicate inequity for all statuses, full immunization coverage is very low at 31.5% suggesting significant gaps in reaching children after initial doses for routine immunizations. Applying the VERSE tool to future Nigeria DHS surveys can allow decisionmakers to track changes in vaccination coverage equity, in a standardized manner, over time.

Comparing Multivariate with Wealth-Based Inequity in Vaccination Coverage in 56 Countries: Toward a Better Measure of Equity in Vaccination Coverage.

Following a call from the World Health Organization in 2017 for a methodology to monitor immunization coverage equity in line with the 2030 Agenda for Sustainable Development, this study applies the Vaccine Economics Research for Sustainability and Equity (VERSE) vaccination equity toolkit to measure national-level inequity in immunization coverage using a multidimensional ranking procedure and compares this with traditional wealth-quintile based ranking methods for assessing inequity. The analysis covers 56 countries with a most recent Demographic & Health Survey (DHS) between 2010 and 2022. The vaccines examined include Bacillus Calmette-Guerin (BCG), Diphtheria-Tetanus-Pertussis-containing vaccine doses 1 through 3 (DTP1-3), polio vaccine doses 1-3 (Polio1-3), the measles-containing vaccine first dose (MCV1), and an indicator for being fully immunized for age with each of these vaccines. The VERSE equity toolkit is applied to 56 DHS surveys to rank individuals by multiple disadvantages in vaccination coverage, incorporating place of residence (urban/rural), geographic region, maternal education, household wealth, sex of the child, and health insurance coverage. This rank is used to estimate a concentration index and absolute equity coverage gap (AEG) between the top and bottom quintiles, ranked by multiple disadvantages. The multivariate concentration index and AEG are then compared with traditional concentration index and AEG measures, which use household wealth as the sole criterion for ranking individuals and determining quintiles. We find significant differences between the two sets of measures in almost all settings. For fully-immunized for age status, the inequities captured using the multivariate metric are between 32% and 324% larger than what would be captured examining inequities using traditional metrics. This results in a missed coverage gap of between 1.1 and 46.4 percentage points between the most and least advantaged. The VERSE equity toolkit demonstrated that wealth-based inequity measures systematically underestimate the gap between the most and least advantaged in fully-immunized for age coverage, correlated with maternal education, geography, and sex by 1.1-46.4 percentage points, globally. Closing the coverage gap between the bottom and top wealth quintiles is unlikely to eliminate persistent socio-demographic inequities in either coverage or access to vaccines. The results suggest that pro-poor interventions and programs utilizing needs-based targeting, which reflects poverty only, should expand their targeting criteria to include other dimensions to reduce systemic inequalities, holistically. Additionally, a multivariate metric should be considered when setting targets and measuring progress toward reducing inequities in healthcare coverage.

ASSESSING NONSAMPLING BIAS ERROR AMONG SEXUAL MINORITY OLDER ADULTS IN THE CENSUS' HOUSEHOLD PULSE SURVEY

Abstract Previous research shows data quality and nonsampling bias error reduce accuracy of COVID-19 vaccination coverage in the Census' Household Pulse Survey. However, it is unclear how these issues relate to older sexual minority populations. Moreover, previous research has shown that sexual minority older adults survey nonparticipation rates are similar to their heterosexual older adult peers. Yet, it is less clear whether racial/ethnic variability in nonparticipation rates and patterns of missingness among sexual minority older adults exist. The current investigation utilizes repeated pooled data from the Census' Household Pulse Survey (N=329,078) to fill these gaps. Findings reveal nonsampling bias error contributing to inflated racial/ethnic inequities in vaccination coverage among older sexual minorities, with distinct racial/ethnic variability in missingness patterns among sexual minority older adults. The paper concludes with recommendations for improving survey-based research and details suggestions to improve recruitment strategies that minimize nonsampling bias.

Estimates of the number and distribution of zero-dose and under-immunised children across remote-rural, urban, and conflict-affected settings in low and middle-income countries.

While there has been great success in increasing the coverage of new childhood vaccines globally, expanding routine immunization to reliably reach all children and communities has proven more challenging in many low- and middle-income countries. Achieving this requires vaccination strategies and interventions that identify and target those unvaccinated, guided by the most current and detailed data regarding their size and spatial distribution. Through the integration and harmonisation of a range of geospatial data sets, including population, vaccination coverage, travel-time, settlement type, and conflict locations. We estimated the numbers of children un- or under-vaccinated for measles and diphtheria-tetanus-pertussis, within remote-rural, urban, and conflict-affected locations. We explored how these numbers vary both nationally and sub-nationally, and assessed what proportions of children these categories captured, for 99 lower- and middle-income countries, for which data was available. We found that substantial heterogeneities exist both between and within countries. Of the total 14,030,486 children unvaccinated for DTP1, over 11% (1,656,757) of un- or under-vaccinated children were in remote-rural areas, more than 28% (2,849,671 and 1,129,915) in urban and peri-urban areas, and up to 60% in other settings, with nearly 40% found to be within 1-hour of the nearest town or city (though outside of urban/peri-urban areas). Of the total number of those unvaccinated, we estimated between 6% and 15% (826,976 to 2,068,785) to be in conflict-affected locations, based on either broad or narrow definitions of conflict. Our estimates provide insights into the inequalities in vaccination coverage, with the distributions of those unvaccinated varying significantly by country, region, and district. We demonstrate the need for further inquiry and characterisation of those unvaccinated, the thresholds used to define these, and for more country-specific and targeted approaches to defining such populations in the strategies and interventions used to reach them.

Measles seroprevalence in persons over one year of age in Chandigarh, India

ABSTRACT Measles continues to result in focal outbreaks in India, despite over three decades of universal infant vaccination. The aims of this study were to examine measles immunity in the population of Chandigarh, India, and to compare immunity by vaccination vs. natural infection. In a cross-sectional study of individuals 1–60 years selected from 30 communities within Chandigarh during 2017–2018, measles immunity was assessed using serological surveys. Seropositivity was compared across demographic groups, and by prior history of vaccination and natural history of infection. Among those 1–20 years old, measles seropositivity, and histories of measles vaccination or prior measles diagnosis were separately assessed as outcomes in logistic regression models, with demographic factors as independent variables. Among 1690 participants, 94% were seropositive, and 6% had borderline or negative antibody levels. Of those positive, 30% had prior vaccination, 16% had a history of natural infection, and 54% had an unknown history. Over 50% of individuals among those >20 years old, had unknown history of immunity. In the multivariable regression models, vaccination was more common in younger ages (P < .0001), and in males compared to females (P = .0220), and in those with more education (P < .0001). The majority of the population was seropositive, and seropositivity increased with age. Older age groups were more likely to be protected because of previous natural infection, whereas younger age groups were protected by vaccination. There was inequity in vaccination coverage by gender, and maternal education status.

Does a pay-for-performance health service model improve overall and rural–urban inequity in vaccination rates? A difference-in-differences analysis from the Gambia

ObjectiveTo assess whether the implementation of a results-based financing (RBF) project in The Gambia resulted in (1) improved national vaccination coverage (2) higher coverage in intervention than non-intervention areas, and (3) improvement in rural–urban coverage inequality. MethodsThe study used a difference-in-differences design, based on repeated cross-sectional data from The Gambian Demographic and Health Surveys 2013 (N = 1650) and 2020 (N = 1456). Full vaccination (receipt of one BCG, 3 OPV, 3 DTP, and 1 measles-containing vaccine doses) and rural–urban vaccination inequality were our outcome variables. The intervention, RBF, was implemented in 5 of the 7 health regions. Covariates controlled for included child’s sex, child’s birth order number, socioeconomic status, ethnicity, distance from health facility, maternal education, mother’s age group, mother’s marital status, and mother’s work status. Poisson regression with robust variance was used to estimate whether coverage changed, and difference-in-differences and difference-in-differences-in-differences were used to ‘assess differences in vaccination coverage change and change in inequalities, respectively. ResultsTotal crude full vaccination coverage in The Gambia was 76% in 2013 and 84.6% in 2020. Overall vaccination significantly increased by 16% (95% CI: 9% to 24%) in 2020 compared to 2013, but with a smaller increase in intervention relative to non-intervention areas [PRR 0.88 (CI: 0.78–0.99)]. Rural-urban inequality in vaccination coverage decreased more – by 13% [0.87 (0.78–0.98)] – in RBF than non-RBF regions. ConclusionVaccination coverage improved over the study period though we have no evidence to ascribe the coverage gains to the RBF intervention. However, our study suggests that the RBF project has contributed to reducing rural–urban inequalities in the regions it was implemented.

Coverage and Drivers to Reaching the Last Child With Vaccination in Urban Settings: A Mixed-Methods Study in Kampala, Uganda.

Limited evidence exists regarding the drivers of vaccination coverage and equity in Kampala city, despite frequent measles outbreaks, inequities in vaccination coverage, and the decline in vaccination coverage rates. This study was designed to determine vaccine coverage among children aged 12-36 months and to understand its demand-side drivers. We utilized a mixed-methods parallel convergent study design. A household survey was conducted to quantify the drivers of vaccine coverage among households with children aged 12-36 months. We employed a multistage sampling approach to select households, using a primary sampling unit of an enumeration area. We conducted 30 key informant interviews, 7 focus group discussions, and 6 in-depth interviews with representatives from the immunization program, health workers, and parents residing in areas with low vaccine coverage. Of the 590 enrolled children, 340 (57.6%) were partially vaccinated, 244 (41.4%) were fully vaccinated and had received all the recommended vaccinations, and 6 (1.0%) had never received any vaccine. Of the 244 with all recommended vaccinations, only 65 (26.6%) received their vaccines on time. Access to vaccination services was high (first dose of diphtheria, pertussis, and tetanus [DPT1] coverage of 96%), but utilization decreased over time, as shown by a dropout rate of 17.3% from the first to third dose of DPT. The main driver of complete vaccination was the parents' appreciation of the benefits of vaccination. Among partially vaccinated children, the barriers to vaccination were inadequate information about vaccination (its benefits and schedule), vaccine stock-outs, long waiting times to receive vaccination services, and hidden vaccination costs. Vaccination needs to be targeted to all children irrespective of whether they reside in slum areas or nonslum areas, as most are under-vaccinated. Social mobilization and communication efforts should be tailored to the complexities of urban settings characterized by transient and diverse populations with different cultures.

Association of Zip Code Vaccination Rate With COVID-19 Mortality in Chicago, Illinois

There has been large geographic inequity in vaccination coverage across Chicago, Illinois, with higher vaccination rates in zip codes with residents who predominantly have high incomes and are White. To determine the association between inequitable zip code-level vaccination coverage and COVID-19 mortality in Chicago. This retrospective cohort study used Chicago Department of Public Health vaccination and mortality data and Cook County Medical Examiner mortality data from March 1, 2020, through November 6, 2021, to assess the association of COVID-19 mortality with zip code-level vaccination rates. Data were analyzed from June 1, 2021, to April 13, 2022. Zip code-level first-dose vaccination rates before the Alpha and Delta waves of COVID-19. The primary outcome was deaths from COVID-19 during the Alpha and Delta waves. The association of a marginal increase in zip code-level vaccination rate with weekly mortality rates was estimated with a mixed-effects Poisson regression model, and the total number of preventable deaths in the least vaccinated quartile of zip codes was estimated with a linear difference-in-difference design. The study population was 2 686 355 Chicago residents in 52 zip codes (median [IQR] age 34 [32-38] years; 1 378 658 [51%] women; 773 938 Hispanic residents [29%]; 783 916 non-Hispanic Black residents [29%]; 894 555 non-Hispanic White residents [33%]). Among residents in the least vaccinated quartile, 80% were non-Hispanic Black, compared with 8% of residents identifying as non-Hispanic Black in the most vaccinated quartile (P < .001). After controlling for age distribution and recovery from COVID-19, a 10-percentage point increase in zip code-level vaccination 6 weeks before the peak of the Alpha wave was associated with a 39% lower relative risk of death from COVID-19 (incidence rate ratio [IRR], 0.61 [95% CI, 0.52-0.72]). A 10-percentage point increase in zip code vaccination rate 6 weeks before the peak of the Delta wave was associated with a 24% lower relative risk of death (IRR, 0.76 [95% CI, 0.66-0.87]). The difference-in-difference estimate was that 119 Alpha wave deaths (72% [95% CI, 63%-81%]) and 108 Delta wave deaths (75% [95% CI, 66%-84%]) might have been prevented in the least vaccinated quartile of zip codes if it had had the vaccination coverage of the most vaccinated quartile. These findings suggest that low zip code-level vaccination rates in Chicago were associated with more deaths during the Alpha and Delta waves of COVID-19 and that inequitable vaccination coverage exacerbated existing racial and ethnic disparities in COVID-19 deaths.

COVID-19 vaccination coverage in deprived populations living in segregated colonies: A nationwide cross-sectional study in Hungary.

The segregated colonies (SCs) in Hungary are populated mainly but not exclusively by Roma. Their health care use is restricted in many respects. It has not been studied yet, whether fair COVID-19 vaccination coverage achieved in Hungary is accompanied with fair effectiveness in SCs. Using census data, the vaccination coverage in SCs and the complementary areas (CAs) in the same settlements of the country was determined. To describe the settlement level differences, the vaccination coverage (until June 30, 2021) in SCs were compared to those in CAs by age, sex, and eligibility for exemption certificate standardized measures. Aggregating settlement level data, the level of geographic discrimination in Hungary was also determined. According to nationwide aggregates, crude vaccination coverage was significantly lower in SCs (40.05%, 95% CI 39.87%-40.23%) than in CAs (65.42%, 95% CI 65.37%-65.46%). The relative standardized vaccination coverage was 0.643 (95% CI 0.639-0.647) in SCs. A total of 437 of the 938 investigated settlements showed significant local vaccination disparities. Hungarian citizens living in SCs, mainly of Roma ethnicity, are a distinct high-risk group. Special intervention adapted to SCs is needed to mitigate inequality in vaccination coverage and further consequences of the pandemic.

Multi-level policy responses to tackle socioeconomic inequalities in the incidence of COVID-19 in a European urban area

BackgroundSpain has been hit hard by COVID-19 since March 2020, especially in its metropolitan areas. We share experiences from Barcelona in measuring socioeconomic inequalities in the incidence of COVID-19 in the different waves, and in implementing coordinated and equity-oriented public health policy responses.MethodsWe collected daily data on confirmed COVID-19 cases, geocoded the address of residence to assign each case to one of the 73 neighborhoods and 1068 census tracts, and calculated the cumulative incidence of COVID-19 by neighborhood and five income groups (quintiles of census tracts) by sex across four waves of the pandemic. We adjusted hierarchical Bayesian spatial models to obtain the relative risk (RR) of cumulative incidences in each quintile compared with the richest areas. A variety of public health policies implemented to tackle the pandemic and especially these inequalities in COVID-19 incidence and vaccination are selected and described.ResultsArea-level income inequalities in the incidence of COVID-19 were present at different degree in all four waves. In the second wave (10/1/2020 to 12/6/2020), RR for the poorest income quintile census tracts compared with the richest was 1.43 (95% credible interval-CI-: 1.22–1.67) for men and 1.58 (95% CI: 1.35–1.83) for women. Later, inequalities in vaccination coverage also arose. Equity-oriented policy responses included: “health hotels” or home delivery of basic products for individuals with COVID-19 and without adequate conditions for isolation; new emergency facilities for homeless people, including those with active drug use; mass screening in high incidence areas; contingency plans for nursing homes and schools; adapting community health programs for their early reactivation; digital self-appointment support points and community vaccination days.ConclusionCOVID-19 hit Barcelona neighborhoods unequally, with variations between waves. The rapid availability of geolocalized data and by socioeconomic level helped public authorities to implement targeted policies and collaborative interventions for the most vulnerable populations. Further studies would be needed to evaluate their impact.

Unmet need for COVID-19 vaccination coverage in Kenya

COVID-19 has impacted the health and livelihoods of billions of people since it emerged in 2019. Vaccination for COVID-19 is a critical intervention that is being rolled out globally to end the pandemic. Understanding the spatial inequalities in vaccination coverage and access to vaccination centres is important for planning this intervention nationally. Here, COVID-19 vaccination data, representing the number of people given at least one dose of vaccine, a list of the approved vaccination sites, population data and ancillary GIS data were used to assess vaccination coverage, using Kenya as an example. Firstly, physical access was modelled using travel time to estimate the proportion of population within 1 hour of a vaccination site. Secondly, a Bayesian conditional autoregressive (CAR) model was used to estimate the COVID-19 vaccination coverage and the same framework used to forecast coverage rates for the first quarter of 2022. Nationally, the average travel time to a designated COVID-19 vaccination site (n = 622) was 75.5 min (Range: 62.9 – 94.5 min) and over 87% of the population >18 years reside within 1 hour to a vaccination site. The COVID-19 vaccination coverage in December 2021 was 16.70% (95% CI: 16.66 – 16.74) – 4.4 million people and was forecasted to be 30.75% (95% CI: 25.04 – 36.96) – 8.1 million people by the end of March 2022. Approximately 21 million adults were still unvaccinated in December 2021 and, in the absence of accelerated vaccine uptake, over 17.2 million adults may not be vaccinated by end March 2022 nationally. Our results highlight geographic inequalities at sub-national level and are important in targeting and improving vaccination coverage in hard-to-reach populations. Similar mapping efforts could help other countries identify and increase vaccination coverage for such populations.

Vaccine supply chains in resource-limited settings: Mitigating the impact of rainy season disruptions

Immunization is widely recognized as one of the most successful and cost-effective health interventions, preventing two to three million deaths from vaccine-preventable diseases each year. Although progress has been made in recent years, substantial operational challenges persist in resource-limited settings with frequent stock-outs contributing to sub-optimal immunization coverage and inequality in vaccine access. In this paper, we investigate the role of rainy season induced supply chain disruptions on vaccination coverage and inequalities. We develop a modeling framework combining spatial modeling—to predict flood disruptions in road networks—and a discrete-event simulation of a multi-tiered vaccine supply chain (VSC). Our models are fitted using data from the Malagasy VSC network and validated to the best extent possible with scarce data. Our baseline simulation predicts the national vaccination coverage with good accuracy and suggests that 67% of regions with low reported immunization coverage are affected by rainy season disruptions or operational inefficiencies, causing significant geographical inequalities in vaccine access. We investigate various mitigation strategies to increase the resiliency of VSCs and find that, by strategically placing buffer inventory at targeted facilities prior to the rainy season, the proportion of children receiving all basic vaccines in these areas is increased by 8% and the geographical inequality in vaccination coverage between areas affected and not affected by the rainy season is reduced by 11%. By also increasing the replenishment frequency from every third month to every month, the national vaccination coverage improves by 41%. Our results contribute to achieving the UN Sustainable Development Goals (SDGs) by providing actionable insights for improving vaccination coverage (SDG 3) and investigating the resiliency of the VSC to increased flooding due to climate change (SDG 13).

Decomposing socio-economic inequality in vaccination coverage among Pakistani children: A population-based cross-sectional study.

There is scarce knowledge about factors contributing to underlying inequalities in vaccination coverage among Pakistani children. Therefore, the main objective of this study is to measure and decompose socioeconomic inequalities in childhood vaccination coverage. Pakistan Demographic and Health Survey, version 2017-18, data were used for analysis. Bivariate association was checked through Chi-square test and concentration curve (CC) and concentration index (CI) were used to assess the existence and nature of inequality. Finally, decomposition analysis was performed to measure the contribution of different factors to the observed inequality. Our findings suggested that vaccination coverage is more concentrated among children of educated mothers (CI=0.296) and decomposition results suggest that a substantial proportion of the inequality is explained by maternal education, wealth status, paternal education and improved sanitation (34%, 19%, 14% and 21% respectively). Also, differences are observed between regions regarding vaccination coverage. There is need of female-targeted interventions to increase maternal role in the society through better education and decision-making autonomy. Also, the policies to improve the household's wealth status should be considered.

Effects of geographic and economic heterogeneity on the burden of rotavirus diarrhea and the impact and cost-effectiveness of vaccination in Nigeria.

Child mortality from rotavirus gastroenteritis remains high in Nigeria, representing 14% of all rotavirus deaths worldwide. Here, we examine the potential impact and cost-effectiveness of national rotavirus vaccine introduction in geographic and economic subpopulations of Nigeria. We projected the health and economic outcomes of rotavirus vaccination in children over the first five years of life using a spreadsheet-based model. We modeled child populations using national survey data on rotavirus mortality risk factors and vaccination coverage to predict burden and impact across regional and wealth quintile subpopulations within Nigeria. Our base case considered introduction of a general rotavirus vaccine, modeled to encompass characteristics of existing vaccines, versus no vaccine. Base case costs were estimated from the government perspective, assuming Gavi subsidies, over the first five years. We also present estimates from the cost of vaccination from the perspective of Gavi. We explored uncertainty in model parameters through probabilistic uncertainty, one-way sensitivity, and scenario analyses. According to our estimates, rotavirus enteritis was responsible for 47,898 [95% Uncertainty Limits: 35,361; 63,703] child deaths per year, with approximately 80% of the national burden concentrated in the three northern regions of Nigeria. Rotavirus vaccination was estimated to prevent 6,454 [3,960; 9,721] deaths, 13% [9%; 18%] of the national annual RV burden. National ICERs for rotavirus vaccination from the Nigerian government and Gavi perspectives were US$47 [$18; $105] and $62 [$29; $130] per DALY averted, respectively. General rotavirus vaccination was projected to reduce rotavirus mortality by only 6% [4%; 9%] in the North West region compared to 35% [24%; 47%] in the South East region. Base case ICERs ranged from US$25 [10; 56] per DALY averted in North West to US$64 [18; 157] per DALY averted in South South. Gavi perspective ICERs ranged from US$33 [$15; $68] in North West to US$88 [35; 191] per DALY averted in South South. According to one-way sensitivity analyses, ICERs were most sensitive to vaccine efficacy, followed by estimated administrative costs and rotavirus mortality. Disparities in mortality reduction were largely driven by inequality in vaccination coverage across regions and between socioeconomic subpopulations. Due to high, persistent, and inequitable burden of rotavirus in Nigeria, routine vaccination with any of these rotavirus vaccines would be an high impact and cost-effective strategy in reducing child mortality.

Vaccine Supply Chains in Resource-Limited Settings: Mitigating Rainy Season Disruptions

Immunization is widely recognized as one of the most successful and cost-effective health interventions, preventing two to three million deaths from vaccine-preventable diseases each year. Although progress has been made in recent years, substantial operational challenges persist in resource-limited settings with frequent stock-outs contributing to sub-optimal immunization coverage and inequality in vaccine access. In this paper, we investigate the role of rainy season induced supply chain disruptions on vaccination coverage and inequalities. We develop a modeling framework combining spatial modeling — to predict flood disruptions in road networks — and a discrete-event simulation of a multi-tiered vaccine supply chain (VSC). Our models are fitted and validated using data from the Malagasy VSC network. Our baseline simulation predicts the national vaccination coverage with good accuracy and suggests that 67% of regions with low reported immunization coverage are affected by rainy season disruptions or operational inefficiencies, causing significant geographical inequalities in vaccine access. We investigate various mitigation strategies to increase the resiliency of VSCs and find that by strategically placing buffer inventory at targeted facilities prior to the rainy season the proportion of children receiving all basic vaccines in these areas is increased by 7% and the geographical inequality in vaccination coverage is reduced by 11%. By also increasing the replenishment frequency from every third month to every month, the national vaccination coverage improves by 37%. Our results contribute to achieving the UN Sustainable Development Goals (SDGs) by providing actionable insights for improving vaccination coverage (SDG 3) and investigating the resiliency of the VSC to increased flooding due to climate change (SDG 13).