Routine Immunization Coverage Research Articles

Study protocol for a cluster-randomised controlled trial of hybrid parents and health workers adaptive intervention for optimal routine childhood immunisation coverage in the communities of Ebonyi state, Nigeria: the AGINTOPIC trial protocol

IntroductionVaccine-preventable infectious diseases (VPDs) are major causes of morbidity/mortality among children under 5 years of age worldwide and in Nigeria/Ebonyi state. Routine childhood immunisation is an invaluable prevention strategy for...

Progress Toward Rubella Elimination - World Health Organization South-East Asia Region, 2013-2021.

During 2013, the 11 countries of the World Health Organization (WHO) South-East Asia Region* (SEAR) adopted the goals of measles elimination and rubella and congenital rubella syndrome (CRS) control† by 2020. During 2019, SEAR countries declared a broader goal for eliminating both measles and rubella§ by 2023 (1). Before 2013, only five SEAR countries had introduced rubella-containing vaccine (RCV). This report updates a previous report and describes progress toward rubella elimination in SEAR during 2013-2021 (2). During 2013-2021, six SEAR countries introduced RCV; all countries in the Region now use RCV in routine immunization. Routine immunization coverage with the first dose of a rubella-containing vaccine (RCV1) increased >600%, from 12% during 2013 to 86% during 2021, and an estimated 515 million persons were vaccinated via RCV supplementary immunization activities (SIAs)¶ during 2013-2021. During this time, annual reported rubella incidence declined by 80%, from 5.5 to 1.1 cases per million population. Maldives and Sri Lanka are verified as having achieved rubella elimination; Bhutan, North Korea, and Timor-Leste have halted endemic transmission of rubella virus for >36 months. SEAR has made substantial progress toward rubella elimination; however, intensified measures are needed to achieve elimination.

Halting vaccine-derived poliovirus circulation: the novel type 2 oral vaccine might not be enough

Halting vaccine-derived poliovirus circulation: the novel type 2 oral vaccine might not be enough

Update on Vaccine-Derived Poliovirus Outbreaks - Worldwide, January 2021-December 2022.

Circulating vaccine-derived poliovirus (cVDPV) outbreaks* can occur when oral poliovirus vaccine (OPV, containing one or more Sabin-strain serotypes 1, 2, and 3) strains undergo prolonged circulation in under-vaccinated populations, resulting in genetically reverted neurovirulent virus (1,2). Following declaration of the eradication of wild poliovirus type 2 in 2015 and the global synchronized switch from trivalent OPV (tOPV, containing Sabin-strain types 1, 2, and 3) to bivalent OPV (bOPV, containing types 1 and 3 only) for routine immunization activities† in April 2016 (3), cVDPV type 2 (cVDPV2) outbreaks have been reported worldwide (4). During 2016-2020, immunization responses to cVDPV2 outbreaks required use of Sabin-strain monovalent OPV2, but new VDPV2 emergences could occur if campaigns did not reach a sufficiently high proportion of children. Novel oral poliovirus vaccine type 2 (nOPV2), a more genetically stable vaccine than Sabin OPV2, was developed to address the risk for reversion to neurovirulence and became available in 2021. Because of the predominant use of nOPV2 during the reporting period, supply replenishment has frequently been insufficient for prompt response campaigns (5). This report describes global cVDPV outbreaks during January 2021-December 2022 (as of February 14, 2023) and updates previous reports (4). During 2021-2022, there were 88 active cVDPV outbreaks, including 76 (86%) caused by cVDPV2. cVDPV outbreaks affected 46 countries, 17 (37%) of which reported their first post-switch cVDPV2 outbreak. The total number of paralytic cVDPV cases during 2020-2022 decreased by 36%, from 1,117 to 715; however, the proportion of all cVDPV cases that were caused by cVDPV type 1 (cVDPV1) increased from 3% in 2020 to 18% in 2022, including the occurrence of cocirculating cVDPV1 and cVDPV2 outbreaks in two countries. The increased proportion of cVDPV1 cases follows a substantial decrease in global routine immunization coverage and suspension of preventive immunization campaigns during the COVID-19 pandemic (2020-2022) (6); outbreak responses in some countries were also suboptimal. Improving routine immunization coverage, strengthening poliovirus surveillance, and conducting timely and high-quality supplementary immunization activities (SIAs) in response to cVDPV outbreaks are needed to interrupt cVDPV transmission and reach the goal of no cVDPV isolations in 2024.

Addressing Determinants of Immunization Inequities Requires Objective Tools to Devise Local Solutions.

Universal immunization substantially reduces morbidity and mortality from vaccine-preventable diseases. In recent years, routine immunization coverage has varied considerably among countries across the WHO European Region, and among different populations and districts within countries. It has even declined in some countries. Sub-optimal immunization coverage contributes to accumulations of susceptible individuals and can lead to outbreaks of vaccine-preventable diseases. The European Immunization Agenda 2030 (EIA2030) seeks to build better health in the WHO European Region by ensuring equity in immunization and supporting immunization stakeholders in devising local solutions to local challenges. The factors that influence routine immunization uptake are context specific and multifactorial; addressing immunization inequities will require overcoming or removing barriers to vaccination for underserved individuals or populations. Local level immunization stakeholders must first identify the underlying causes of inequities, and based on this information, tailor resources, or service provision to the local context, as per the organization and characteristics of the health care system in their countries. To do this, in addition to using the tools already available to broadly identify immunization inequities at the national and regional levels, they will need new pragmatic guidance and tools to address the identified local challenges. It is time to develop the necessary guidance and tools and support immunization stakeholders at all levels, especially those at the subnational or local health centre levels, to make the vision of EIA2030 a reality.

Critical success factors for high routine immunization performance: A case study of Senegal

BackgroundThe essential components of a vaccine delivery system are well-documented, but robust evidence is lacking on how policies and implementation strategies are operationalized to drive catalytic improvements in coverage. To address this gap, we identified success factors that supported improvements in routine immunization coverage in Senegal, especially from 2000 to 2019. MethodsWe identified Senegal as an exemplar in the delivery of childhood vaccines through analysis of DTP1 and DTP3 coverage data. Through interviews and focus group discussions at the national, regional, district, health facility, and community-level, we investigated factors that contributed to high and sustained vaccination coverage. We conducted a thematic analysis through application of implementation science frameworks to determine critical success factors. We triangulated these findings with quantitative analyses using publicly available data. ResultsThe following success factors emerged: 1) Strong political will and prioritization of resources for immunization programming supported urgent allocation of funding and supplies; 2) Collaboration between the Ministry of Health and Social Action and external partners fostered innovation, capacity building, and efficiency; 3) Improved surveillance, monitoring, and evaluation allowed for timely and evidence-based decision making; 4) Community ownership of vaccine service delivery supported tailored programming and response to local needs; and 5) Community health workers spearheaded vaccine promotion and demand generation for vaccines. ConclusionThe vaccination program in Senegal was supported by evidence-based decision making at the national-level, alignment of priorities between governmental entities and external partners, and strong community engagement initiatives that fostered local ownership of vaccine delivery and uptake. High routine immunization coverage was likely driven by prioritization of immunization programming, improved surveillance systems, a mature and reliable community health worker program, and tailored strategies for addressing geographical, social, and cultural barriers.

Real-time prediction model of cVDPV2 outbreaks to aid outbreak response vaccination strategies.

Circulating vaccine-derived poliovirus outbreaks are spreading more widely than anticipated, which has generated a crisis for the global polio eradication initiative. Effectively responding with vaccination activities requires a rapid risk assessment. This assessment is made difficult by the low case-to-infection ratio of type 2 poliovirus, variable transmissibility, changing population immunity, surveillance delays, and limited vaccine supply from the global stockpile. The geographical extent of responses have been highly variable between countries. We develop a statistical spatio-temporal model of short-term, district-level poliovirus spread that incorporates known risk factors, including historical wild poliovirus transmission risk, routine immunization coverage, population immunity, and exposure to the outbreak virus. We find that proximity to recent cVDPV2 cases is the strongest risk factor for spread of an outbreak, and find significant associations between population immunity, historical risk, routine immunization, and environmental surveillance (p<0.05). We examine the fit of the model to type 2 vaccine derived poliovirus spread since 2016 and find that our model predicts the location of cVDPV2 cases well (AUC=0.96). We demonstrate use of the model to estimate appropriate scope of outbreak response activities to current outbreaks. As type 2 immunity continues to decline following the cessation of tOPV in 2016, outbreak responses to new cVDPV2 detections will need to be faster and larger in scope. We provide a framework that can be used to support decisions on the appropriate size of a vaccination response when new detections are identified. While the model does not account for all relevant local factors that must be considered in the overall vaccination response, it enables a quantitative basis for outbreak response size.

The Hidden Impact of the COVID-19 Pandemic on Routine Childhood Immunization Coverage in Cameroon.

Background: The third round of the global pulse survey demonstrated that the abrupt and rapid progression of the COVID-19 pandemic significantly disrupted childhood immunization in many countries. Although Cameroon has reported over 120,000 COVID-19 cases, the reported national childhood vaccination coverage during the pandemic seems to have increased compared to that during the pre-COVID-19 period. Indeed, the first dose of the diphtheria, tetanus, and pertussis-containing vaccine (DTP-1) coverage increased from 85.4% in 2019 to 87.7% in 2020, and DTP-3 coverage increased from 79.5% in 2019 to 81.2% in 2020. The paucity of literature on the impact of COVID-19 on childhood vaccination in COVID-19 hotspot regions poses a challenge in developing a context-specific immunization recovery plan, hence the need to conduct this study. Methodology: We conducted a cross-sectional study using 2019 (pre-pandemic period) and 2020 (pandemic period) district childhood immunization data from the DHIS-2 database, weighted using completeness for each data entry against regional data completeness in 2020. Based on COVID-19 incidence, two hotspot regions were selected, with all districts (56/56) included in the final analysis. The Chi-square test was used to compare DTP-1 and DTP-3 coverage during the pre-pandemic and pandemic periods. Results: In the two hotspot regions, 8247 children missed DTP-1, and 12,896 children did not receive DTP-3 vaccines in the pandemic period compared to the results from the pre-pandemic period. Indeed, there was a significant drop in DTP-1 and DTP-3 coverage of 0.8% (p = 0.0002) and 3.1% (p = 0.0003), respectively, in the Littoral Region. Moreover, the Centre Region reported a 5.7% (p < 0.0001) and 7.6% (p < 0.0001) drop in DTP-1 and DTP-3 coverage, respectively. Most districts in the hotspot regions reported a decline in childhood immunization access (62.5%) and utilization (71.4%). Indeed, in the Littoral Region, 46% (11/24) and 58% (14/24) of districts experienced decreased vaccination access and utilization, respectively. Meanwhile, 75% (24/32) and 81% (26/32) of districts in the Centre Region experienced a drop in vaccination access and utilization, respectively. Conclusion: This study reported a situation where the national immunization indicators mask the impact of COVID-19 on childhood immunization in heavily hit regions. Therefore, this study presents valuable information for ensuring continuous vaccination service delivery during public health emergencies. The findings could also contribute to developing an immunization recovery plan and informing policy on future pandemic preparedness and response.

Studying Vaccination Coverage and Design of Short Message Service Based Reminder to Improve Children Vaccination Coverage in Hawassa; Sidama Region; Ethiopia

A vaccine is a kind of remedy that trains the body’s protection system so that it can combat an infection. The national routine immunization coverage in Ethiopia is low. Among the main reason for defaulting children vaccinations are disremembering the appointment date, communication gap between service providers and the community, knowhow about vaccination and etc. This work is to investigate vaccination coverage in Hawassa city and main reasons of vaccination drop out, and then provide a solution for that main reason. Data was collected from 360 children whose age is between 1 to 2 years who live in Hawassa city. The data analysis result showed that only 51% of the children are fully vaccinated; and the main reason for vaccination dropout which weighs 57% was found to be disremembering the appointment date. Providing a solution to not only one of the main reasons but also for the one which weighs the most in the city of this study will improve the vaccination coverage. As the main reason is found to be disremembering the vaccination appointment date, this work provides a Short Message Service (SMS) based automatic reminding system. The design part uses database, OzekiNG network gateway and global system for mobile communication modem with active subscriber identity module. In this system the health extension workers will register the clients’ detailed information including appointment dates during the birth of baby that will be accessed periodically by the OzekiNG to send the reminder SMS to the mothers one day a head to the day of vaccination. After automatic reminding mechanism was developed and implemented, coverage of fully vaccinated children increases from 51% to 71% and the problem of forgetting appointment date decreases from 57% to 14%. The efficiency of the developed system is found to be 85%. From the above-mentioned results and the current available communication mechanisms, it can be concluded that the reminding system can be simply implemented to improve the child vaccination coverage by bridging the gap due to disremembering the vaccination appointment date.

Studying Vaccination Coverage and Design of Short Message Service Based Reminder to Improve Children Vaccination Coverage in Hawassa; Sidama Region; Ethiopia

A vaccine is a kind of remedy that trains the body’s protection system so that it can combat an infection. The national routine immunization coverage in Ethiopia is low. Among the main reason for defaulting children vaccinations are disremembering the appointment date, communication gap between service providers and the community, knowhow about vaccination and etc. This work is to investigate vaccination coverage in Hawassa city and main reasons of vaccination drop out, and then provide a solution for that main reason. Data was collected from 360 children whose age is between 1 to 2 years who live in Hawassa city. The data analysis result showed that only 51% of the children are fully vaccinated; and the main reason for vaccination dropout which weighs 57% was found to be disremembering the appointment date. Providing a solution to not only one of the main reasons but also for the one which weighs the most in the city of this study will improve the vaccination coverage. As the main reason is found to be disremembering the vaccination appointment date, this work provides a Short Message Service (SMS) based automatic reminding system. The design part uses database, OzekiNG network gateway and global system for mobile communication modem with active subscriber identity module. In this system the health extension workers will register the clients’ detailed information including appointment dates during the birth of baby that will be accessed periodically by the OzekiNG to send the reminder SMS to the mothers one day a head to the day of vaccination. After automatic reminding mechanism was developed and implemented, coverage of fully vaccinated children increases from 51% to 71% and the problem of forgetting appointment date decreases from 57% to 14%. The efficiency of the developed system is found to be 85%. From the above-mentioned results and the current available communication mechanisms, it can be concluded that the reminding system can be simply implemented to improve the child vaccination coverage by bridging the gap due to disremembering the vaccination appointment date.

Studying Vaccination Coverage and Design of Short Message Service Based Reminder to Improve Children Vaccination Coverage in Hawassa; Sidama Region; Ethiopia

A vaccine is a kind of remedy that trains the body’s protection system so that it can combat an infection. The national routine immunization coverage in Ethiopia is low. Among the main reason for defaulting children vaccinations are disremembering the appointment date, communication gap between service providers and the community, knowhow about vaccination and etc. This work is to investigate vaccination coverage in Hawassa city and main reasons of vaccination drop out, and then provide a solution for that main reason. Data was collected from 360 children whose age is between 1 to 2 years who live in Hawassa city. The data analysis result showed that only 51% of the children are fully vaccinated; and the main reason for vaccination dropout which weighs 57% was found to be disremembering the appointment date. Providing a solution to not only one of the main reasons but also for the one which weighs the most in the city of this study will improve the vaccination coverage. As the main reason is found to be disremembering the vaccination appointment date, this work provides a Short Message Service (SMS) based automatic reminding system. The design part uses database, OzekiNG network gateway and global system for mobile communication modem with active subscriber identity module. In this system the health extension workers will register the clients’ detailed information including appointment dates during the birth of baby that will be accessed periodically by the OzekiNG to send the reminder SMS to the mothers one day a head to the day of vaccination. After automatic reminding mechanism was developed and implemented, coverage of fully vaccinated children increases from 51% to 71% and the problem of forgetting appointment date decreases from 57% to 14%. The efficiency of the developed system is found to be 85%. From the above mentioned results and the current available communication mechanisms, it can be concluded that the reminding system can be simply implemented to improve the child vaccination coverage by bridging the gap due to disremembering the vaccination appointment date.

Is the maternal health voucher scheme associated with increasing routine immunization coverage? Experience from Bangladesh.

Bangladesh initiated the Maternal Health Voucher Scheme (MHVS) in 2007 to improve maternal and child health practices and bring equity to the mainstream of health systems by reducing financial and institutional barriers. In this study, we investigated whether the MHVS has an association with immunization coverage in a rural area of Bangladesh. Between 30 October 2016 and 15 June 2017, we carried out a cross-sectional survey in two low performing areas in terms of immunization coverage- Chattogram (erstwhile Chittagong division) and Sylhet division of Bangladesh. We calculated the coverage of fully immunized children (FIC) for 1151 children aged 12-23 months of age. We compared the coverage of FIC between children whose mothers enrolled in MHVS and children whose mother did not. We analyzed immunization coverage using crude odds ratio (OR) and adjusted OR (aOR) from binary logistic regression models. The overall coverage of FIC was 86%. Ninety-three percent children whose mothers were MHVS members were fully immunized whereas the percentage was 84% for the children of mothers who were not enrolled in MHVS. Multivariate analysis also shows that FIC coverage was higher for children whose mothers enrolled in MHVS compared to those children whose mothers did not; the aOR was 2.03 (95% confidence interval 1.11-3.71). MHVS provides a window for non-targeted benefits of childhood vaccination. Providing health education to pregnant mothers during prenatal care may motivate them to immunize their children. Programmes targeted for mothers during pregnancy, childbirth and post-natal may further increase utilization of priority health services such as childhood immunization.

Reasons for reductions in routine childhood immunisation uptake during the COVID-19 pandemic in low- and middle-income countries: A systematic review.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in a substantial decline in routine immunisation coverage in children globally, especially in low- and middle-income countries (LMICs). This study summarises the reasons for disruptions to routine child immunisations in LMICs. A systematic review (PROSPERO CRD42021286386) was conducted following PRISMA 2020 guidelines. Six databases were searched: MEDLINE, Embase, Global Health, CINAHL, Scopus and MedRxiv, on 11/02/2022. Observational and qualitative studies published from January 2020 onwards were included if exploring reasons for missed immunisations during the COVID-19 pandemic in LMICs. Study appraisal used National Heart, Lung, and Blood Institute and Critical Appraisal Skills Programme tools. Reasons for disruption were defined with descriptive codes; cross-sectional (quantitative) data were summarised as mean percentages of responses weighted by study population, and qualitative data were summarised narratively. A total of thirteen studies were included describing reasons behind disruptions; 7 cross-sectional (quantitative), 5 qualitative and 1 mixed methods. Seventeen reasons for disruptions were identified. In quantitative studies (total respondents = 2,853), the most common reasons identified were fear of COVID-19 and consequential avoidance of health centres (41.2%, SD ±13.3%), followed by transport challenges preventing both families and healthcare professionals from reaching vaccination services (11.1% SD ±16.6%). Most reasons stemmed from reduced healthcare-seeking (83.4%), as opposed to healthcare-delivery issues (15.2%). Qualitative studies showed a more even balance of healthcare-seeking (49.5%) and healthcare-delivery issues (50.5%), with fear of COVID-19 remaining a major identified issue (total respondents = 92). The most common reasons for disruption were parental fear of COVID-19 and avoidance of health services. Health systems must therefore prioritise public health messaging to encourage vaccine uptake and recovery of missed immunisations.

Meningococcal A conjugate vaccine coverage in the meningitis belt of Africa from 2010 to 2021: a modelling study

As of the end of 2021, twenty-four countries in the African meningitis belt have rolled out mass campaigns of MenAfriVac®, a meningococcal A conjugate vaccine (MACV) first introduced in 2010. Twelve have completed introduction of MACV into routine immunisation (RI) schedules. Although select post-campaign coverage data are published, no study currently comprehensively estimates MACV coverage from both routine and campaign sources in the meningitis belt across age, country, and time. In this modelling study, we assembled campaign data from the twenty-four countries that had introduced any immunisation activity during or before the year 2021 (Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Côte d'Ivoire, Democratic Republic of the Congo, Ethiopia, Eritrea, the Gambia, Ghana, Guinea, Guinea Bissau, Kenya, Mali, Mauritania, Niger, Nigeria, Senegal, South Sudan, Sudan, Togo and Uganda) via WHO reports and RI data via systematic review. Next, we modelled RI coverage using Spatiotemporal Gaussian Process Regression. Then, we synthesized these estimates with campaign data into a cohort model, tracking coverage for each age cohort from age 1 to 29 years over time for each country. Coverage in high-risk locations amongst children aged 1-4 in 2021 was estimated to be highest in Togo with 96.0% (95% uncertainty interval [UI] 92.0-99.0), followed by Niger with 87.2% (95% UI 85.3-89.0) and Burkina Faso, with 86.4% (95% UI 85.1-87.6). These countries had high coverage values driven by an initial successful mass immunisation campaign, followed by a catch-up campaign, followed by introduction of RI. Due to the influence of older mass vaccination campaigns, coverage proportions skewed higher in the 1-29 age group than the 1-4 group, with a median coverage of 82.9% in 2021 in the broader age group compared to 45.6% in the narrower age group. These estimates highlight where gaps in immunisation remain and emphasise the need for broader efforts to strengthen RI systems. This methodological framework can be applied to estimate coverage for any vaccine that has been delivered in both routine and supplemental immunisation activities. Bill and Melinda Gates Foundation.

Routine Immunization Coverage and Immunization Card Retention in Pakistan: Results From a Cross-sectional National Survey.

Immunization is one of the most successful public health interventions available, saving millions of lives from death and disability each year. Therefore, improving immunization coverage is a high priority for the Government of Pakistan and essential to progress toward universal health coverage. This survey reports the national and provincial/regional coverage and determinants of fully, partially, and not-vaccinated children 12-23 months of age, antigen-wise coverage, percentage of home-based vaccination records (HBR) retention, and reasons for nonretention; dropout, timeliness, and prevalence of missed opportunities for simultaneous vaccination (MOSV). The survey was a descriptive cross-sectional national household survey carried out across Pakistan. The survey included 110,790 children 12-23 months old and their caregivers. A World Health Organization (WHO)-Expanded Program on Immunization (EPI) Survey questionnaire was adapted to collect information. Data were analyzed using the WHO Vaccination Coverage Quality Indicators (VCQI) software and Stata version 17. Nationally excluding Azad Jammu and Kashmir (AJK) and Gilgit Baltistan (GB), the coverage of fully vaccinated children was 76.5%. The likelihood of being fully vaccinated was higher among children of educated parents who belonged to higher wealth quintiles and resided in any province/region other than Balochistan. The main reasons for unimmunization were no faith in immunization, rumors about vaccines, and distance to the facility. About two-thirds (66.2%) of the children had their HBR available, and the main reasons for not having a card were never visiting a health facility and having no awareness about the importance of a card. Dropout was discernible for later doses of vaccines compared with earlier ones. Higher proportions of children received the last doses late by more than two months. Of the 218,002 vaccination visits documented on HBR in the provinces, MOSVs occurred in 17.6% of the visits. The immunization coverage rates provide a direction to strategize the progress to improve the vaccination rates in Pakistan. The country needs to outline the immediate and long-term actions to combat vaccine-preventable diseases, such as escalating integrated immunization campaigns and outreach activities, provision of mobility support, and deploying behavioral interventions as a cross-cutting strategy to improve awareness and reduce misconceptions.

Declining trends in vaccine confidence across sub-Saharan Africa: A large-scale cross-sectional modeling study

ABSTRACT Current WHO/UNICEF estimates of routine childhood immunization coverage reveal the largest sustained decline in uptake in three decades with pronounced setbacks across Africa. Although the COVID-19 pandemic has induced significant supply and delivery disruptions, the impact of the pandemic on vaccine confidence is less understood. We here examine trends in vaccine confidence across eight sub-Saharan countries between 2020 and 2022 via a total of 17,187 individual interviews, conducted via a multi-stage probability sampling approach and cross-sectional design and evaluated using Bayesian methods. Multilevel regression combined with poststratification weighting using local demographic information yields national and sub-national estimates of vaccine confidence in 2020 and 2022 as well as its socio-demographic associations. We identify declines in perceptions toward the importance of vaccines for children across all eight countries, with mixed trends in perceptions toward vaccine safety and effectiveness. We find that COVID-19 vaccines are perceived to be less important and safe in 2022 than in 2020 in six of the eight countries, with the only increases in COVID-19 vaccine confidence detected in Ivory Coast. There are substantial declines in vaccine confidence in the Democratic Republic of Congo and South Africa, notably in Eastern Cape, KwaZulu-Natal, Limpopo, and Northern Cape (South Africa) and Bandundu, Maniema, Kasaï-Oriental, Kongo-Central, and Sud-Kivu (DRC). While over 60-year-olds in 2022 have higher vaccine confidence in vaccines generally than younger age groups, we do not detect other individual-level socio-demographic associations with vaccine confidence at the sample sizes studied, including sex, age, education, employment status, and religious affiliation. Understanding the role of the COVID-19 pandemic and associated policies on wider vaccine confidence can inform post-COVID vaccination strategies and help rebuild immunization system resilience.

China has the momentum to eliminate measles

China has the momentum to eliminate measles

Mapping the distribution of zero-dose children to assess the performance of vaccine delivery strategies and their relationships with measles incidence in Nigeria.

Geographically precise identification and targeting of populations at risk of vaccine-preventable diseases has gained renewed attention within the global health community over the last few years. District level estimates of vaccination coverage and corresponding zero-dose prevalence constitute a potentially useful evidence base to evaluate the performance of vaccination strategies. These estimates are also valuable for identifying missed communities, hence enabling targeted interventions and better resource allocation. Here, we fit Bayesian geostatistical models to map the routine coverage of the first doses of diphtheria-tetanus-pertussis vaccine (DTP1) and measles-containing vaccine (MCV1) and corresponding zero-dose estimates in Nigeria at 1x1 km resolution and the district level using geospatial data sets. We also map MCV1 coverage before and after the 2019 measles vaccination campaign in the northern states to further explore variations in routine vaccine coverage and to evaluate the effectiveness of both routine immunization (RI) and campaigns in reaching zero-dose children. Additionally, we map the spatial distributions of reported measles cases during 2018 to 2020 and explore their relationships with MCV zero-dose prevalence to highlight the public health implications of varying performance of vaccination strategies across the country. Our analysis revealed strong similarities between the spatial distributions of DTP and MCV zero dose prevalence, with districts with the highest prevalence concentrated mostly in the northwest and the northeast, but also in other areas such as Lagos state and the Federal Capital Territory. Although the 2019 campaign reduced MCV zero-dose prevalence substantially in the north, pockets of vulnerabilities remained in areas that had among the highest prevalence prior to the campaign. Importantly, we found strong correlations between measles case counts and MCV RI zero-dose estimates, which provides a strong indication that measles incidence in the country is mostly affected by RI coverage. Our analyses reveal an urgent and highly significant need to strengthen the country's RI program as a longer-term measure for disease control, whilst ensuring effective campaigns in the short term.

Immunization of Children in Africa: Strides and Challenges

Abstract Background: The African continent is behind by a wide margin in the childhood vaccination race which contributes significantly to the high childhood morbidity and mortality rate from vaccine-preventable diseases in the continent. Some African countries are still struggling to achieve routine immunization coverage for all recommended expanded program on immunization vaccines. Aim: In this study, we aimed to identify the barriers hindering childhood immunization in Africa and to identify the remarkable progress made so far. Materials and Methods: Peer-reviewed articles published in English that focused on the barriers to childhood immunization in Africa and the progress made so far was reviewed. This was achieved by searching relevant search terms in PubMed, Google Scholar, Wiley Online Library, and CINAHL databases dating back from January 2000 to June 2022. Result: A total of 30 papers were reviewed. The barriers include parents’ education status, economic status, and gender/age; place of birth and place of residence; cultural beliefs and religious affiliations; fear of contracting diseases and lack of trust in health public institutions; vaccine awareness and delivery; and dose-specific delays. The achievements include international support and oriented actions, plans for technological integration and its implementation, and domestic immunization-oriented actions and research work. Conclusion: Childhood immunization is still low in Africa with the majority of the countries yet to realize the global immunization targets. Technologies and immunization-related interventions have been implemented to support Africa but more concerted effort and aid are required to reduce vaccine-preventable deaths to the bare minimum.

Seroprevalence of poliovirus antibodies in Nigeria: refining strategies to sustain the eradication effort.

in 2016, a switch from trivalent oral poliovirus vaccine (OPV) (containing serotypes 1,2,3) to bivalent OPV (types 1,3) was implemented globally. We assessed the seroprevalence of poliovirus antibody levels in selected Nigerian states, before and after the switch, documented poliovirus type2 outbreak responses conducted and ascertained factors associated with immunity gaps based on seroprevalence rates. we conducted a secondary analysis of stored serum samples from the 2018 Nigeria National HIV/AIDS Indicator and Impact Survey. Serum from 1,185 children aged 0-119 months residing in one southern and four northern states were tested for serotype-specific PV neutralizing antibodies; seropositivity was a reciprocal titer ≥8. We conducted regression analysis to determine sociodemographic risk factors associated with low seroprevalence using SAS 9.4. children aged 24-119 months (pre-switch cohort) had seroprevalence against PV1, PV2, and PV3, of 97.3% (95% CI:96.4-98.2), 93.8% (95% CI:92.2-95.5), and 91.3% (95% CI:89.2-93.4), while children aged <24 months (post-switch) had seroprevalence of 86.0% (95% CI:81.2-90.8), 55.6% (95% CI: 47.7-63.4), and 77.2% (95% CI:71.0-83.4) respectively. Regression analysis showed age <24 months was associated with lower seroprevalence against all PV serotypes, (p<0.0001); females had lower seroprevalence against PV1 (p=0.0184) and PV2 (p=0.0354); northern states lower seroprevalence against PV1 (p=0.0039), while well-water source lower seroprevalence against PV3 (p=0.0288). this study showed high seroprevalence rates against PV 1, 2, and 3 in pre-switch children (aged 24-119 months). However, post-switch children (<24 months) had low immunity against PV2 despite outbreak responses. Strategies to increase routine immunization coverage and high-quality polio campaigns can increase immunity against polio virus.