Comparison of Wealth-Related Inequality in Tetanus Vaccination Coverage before and during Pregnancy: A Cross-Sectional Analysis of 72 Low- and Middle-Income Countries

Immunization of pregnant women against tetanus is a key strategy for reducing tetanus morbidity and mortality while also achieving the goal of maternal and neonatal tetanus elimination. Despite substantial progress in improving newborn protection from tetanus at birth through maternal immunization, umbilical cord practices and sterilized and safe deliveries, inequitable gaps in protection remain. Notably, an infant's tetanus protection at birth is comprised of immunization received by the mother during and before the pregnancy (e.g., through childhood vaccination, booster doses, mass vaccination campaigns, or during prior pregnancies). In this work, we examine wealth-related inequalities in maternal tetanus toxoid containing vaccination coverage before pregnancy, during pregnancy, and at birth for 72 low- and middle-income countries with a recent Demographic and Health Survey or Multiple Indicator Cluster Survey (between 2013 and 2022). We summarize coverage levels and absolute and relative inequalities at each time point; compare the relative contributions of inequalities before and during pregnancy to inequalities at birth; and examine associations between inequalities and coverage levels. We present the findings for countries individually and on aggregate, by World Bank country income grouping, as well as by maternal and neonatal tetanus elimination status, finding that most of the inequality in tetanus immunization coverage at birth is introduced during pregnancy. Inequalities in coverage during pregnancy are most pronounced in low- and lower-middle-income countries, and even more so in countries which have not achieved maternal and neonatal tetanus elimination. These findings suggest that pregnancy is a key time of opportunity for equity-oriented interventions to improve maternal tetanus immunization coverage.

A Practical Guide to Pilot Testing Community-Based Vaccination Coverage Surveys

Pilot testing is crucial when preparing any community-based vaccination coverage survey. In this paper, we use the term pilot test to mean informative work conducted before a survey protocol has been finalized for the purpose of guiding decisions about how the work will be conducted. We summarize findings from seven pilot tests and provide practical guidance for piloting similar studies. We selected these particular pilots because they are excellent models of preliminary efforts that informed the refinement of data collection protocols and instruments. We recommend survey coordinators devote time and budget to identify aspects of the protocol where testing could mitigate project risk and ensure timely assessment yields, credible estimates of vaccination coverage and related indicators. We list specific items that may benefit from pilot work and provide guidance on how to prioritize what to pilot test when resources are limited.

Routine Vaccination Coverage - Worldwide, 2022

In 2020, the World Health Assembly endorsed the Immunization Agenda 2030 (IA2030), the 2021-2030 global strategy that envisions a world where everyone, everywhere, at every age, fully benefits from vaccines. This report reviews trends in World Health Organization and UNICEF immunization coverage estimates at global, regional, and national levels through 2022 and documents progress toward improving coverage with respect to the IA2030 strategy, which aims to reduce the number of children who have not received the first dose of a diphtheria-tetanus-pertussis-containing vaccine (DTPcv1) worldwide by 50% and to increase coverage with 3 diphtheria-tetanus-pertussis-containing vaccine doses (DTPcv3) to 90%. Worldwide, coverage ≥1 dose of DTPcv1 increased from 86% in 2021 to 89% in 2022 but remained below the 90% coverage achieved in 2019. Estimated DTPcv3 coverage increased from 81% in 2021 to 84% in 2022 but also remained below the 2019 coverage of 86%. Worldwide in 2022, 14.3 million children were not vaccinated with DTPcv1, a 21% decrease from 18.1 million in 2021, but an 11% increase from 12.9 million in 2019. Most children (84%) who did not receive DTPcv1 in 2022 lived in low- and lower-middle-income countries. COVID-19 pandemic-associated immunization recovery occurred in 2022 at the global level, but progress was unevenly distributed, especially among low-income countries. Urgent action is needed to provide incompletely vaccinated children with catch-up vaccinations that were missed during the pandemic, restore national vaccination coverage to prepandemic levels, strengthen immunization programs to build resiliency to withstand future unforeseen public health events, and further improve coverage to protect children from vaccine-preventable diseases.

Reasons for Being "Zero-Dose and Under-Vaccinated" among Children Aged 12-23 Months in the Democratic Republic of the Congo

(1) Introduction: The Democratic Republic of the Congo (DRC) has one of the largest cohorts of un- and under-vaccinated children worldwide. This study aimed to identify and compare the main reasons for there being zero-dose (ZD) or under-vaccinated children in the DRC. (2) Methods: This is a secondary analysis derived from a province-level vaccination coverage survey conducted between November 2021 and February 2022; this survey included questions about the reasons for not receiving one or more vaccines. A zero-dose child (ZD) was a person aged 12-23 months not having received any pentavalent vaccine (diphtheria-tetanus-pertussis-Hemophilus influenzae type b (Hib)-Hepatitis B) as per card or caregiver recall and an under-vaccinated child was one who had not received the third dose of the pentavalent vaccine. The proportions of the reasons for non-vaccination were first presented using the WHO-endorsed behavioral and social drivers for vaccination (BeSD) conceptual framework and then compared across the groups of ZD and under-vaccinated children using the Rao-Scott chi-square test; analyses were conducted at province and national level, and accounting for the sample approach. (3) Results: Of the 51,054 children aged 12-23 m in the survey sample, 19,676 ZD and under-vaccinated children were included in the study. For the ZD children, reasons related to people's thinking and feelings were cited as 64.03% and those related to social reasons as 31.13%; both proportions were higher than for under-vaccinated children (44.7% and 26.2%, respectively, p < 0.001). Regarding intentions to vaccinate their children, 82.15% of the parents/guardians of the ZD children said they wanted their children to receive "none" of the recommended vaccines, which was significantly higher than for the under-vaccinated children. In contrast, "practical issues" were cited for 35.60% of the ZD children, compared to 55.60% for the under-vaccinated children (p < 0.001). The distribution of reasons varied between provinces, e.g., 12 of the 26 provinces had a proportion of reasons for the ZD children relating to practical issues that was higher than the national level. (4) Conclusions: reasons provided for non-vaccination among the ZD children in the DRC were largely related to lack of parental/guardian motivation to have their children vaccinated, while reasons among under-vaccinated children were mostly related to practical issues. These results can help inform decision-makers to direct vaccination interventions.

Inequality in Immunization: Holding on to Equity as We 'Catch Up'

Immunization, hailed as one of the most successful public health interventions in the world, has contributed to major advancements in health as well as social and economic development [...].

"Zero Dose" Children in the Democratic Republic of the Congo: How Many and Who Are They?

(1) Background: The Democratic Republic of the Congo (DRC) is one of the countries with the highest number of never vaccinated or "zero-dose" (ZD) children in the world. This study was conducted to examine the proportion of ZD children and associated factors in the DRC. (2) Methods: Child and household data from a provincial-level vaccination coverage survey conducted between November 2021-February 2021 and 2022 were used. ZD was defined as a child aged 12 to 23 months who had not received any dose of pentavalent (diphtheria-tetanus-pertussis-Haemophilus influenzae type b (Hib)-Hepatitis B) vaccine (by card or recall). The proportion of ZD children was calculated and associated factors were explored using logistic regression, taking into account the complex sampling approach. (3) Results: The study included 51,054 children. The proportion of ZD children was 19.1% (95%CI: 19.0-19.2%); ZD ranged from 62.4% in Tshopo to 2.4% in Haut Lomami. After adjustment, being ZD was associated with low level of maternal education and having a young mother/guardian (aged ≤ 19 years); religious affiliation (willful failure to disclose religious affiliation as the highest associated factor compared to being Catholic, followed by Muslims, revival/independent church, Kimbanguist, Protestant); proxies for wealth such as not having a telephone or a radio; having to pay for a vaccination card or for another immunization-related service; not being able to name any vaccine-preventable disease. A child's lack of civil registration was also associated with being ZD. (4) Conclusions: In 2021, one in five children aged 12-23 months in DRC had never been vaccinated. The factors associated with being a ZD child suggest inequalities in vaccination that must be further explored to better target appropriate interventions.

Inequalities in Immunization against Maternal and Neonatal Tetanus: A Cross-Sectional Analysis of Protection at Birth Coverage Using Household Health Survey Data from 76 Countries

Substantial progress in maternal and neonatal tetanus elimination has been made in the past 40 years, with dramatic reductions in neonatal tetanus incidence and mortality. However, twelve countries have still not achieved maternal and neonatal tetanus elimination, and many countries that have achieved elimination do not meet key sustainability thresholds to ensure long-lasting elimination. As maternal and neonatal tetanus is a vaccine-preventable disease (with coverage of the infant conferred by maternal immunization during and prior to pregnancy), maternal tetanus immunization coverage is a key metric for monitoring progress towards, equity in, and sustainability of tetanus elimination. In this study, we examine inequalities in tetanus protection at birth, a measure of maternal immunization coverage, across 76 countries and four dimensions of inequality via disaggregated data and summary measures of inequality. We find that substantial inequalities in coverage exist for wealth (with lower coverage among poorer wealth quintiles), maternal age (with lower coverage among younger mothers), maternal education (with lower coverage among less educated mothers), and place of residence (with lower coverage in rural areas). Inequalities existed for all dimensions across low- and lower-middle-income countries, and across maternal education and place of residence across upper-middle-income countries. Though global coverage changed little over the time period 2001-2020, this obscured substantial heterogeneity across countries. Notably, several countries had substantial increases in coverage accompanied by decreases in inequality, highlighting the need for equity considerations in maternal and neonatal tetanus elimination and sustainability efforts.

Routine Vaccination Coverage - Worldwide, 2021

In 2020, the World Health Assembly endorsed the Immunization Agenda 2030, an ambitious global immunization strategy to reduce morbidity and mortality from vaccine-preventable diseases (1). This report updates a 2020 report (2) with global, regional,* and national vaccination coverage estimates and trends through 2021. Global estimates of coverage with 3 doses of diphtheria-tetanus-pertussis-containing vaccine (DTPcv3) decreased from an average of 86% during 2015-2019 to 83% in 2020 and 81% in 2021. Worldwide in 2021, 25.0 million infants (19% of the target population) were not vaccinated with DTPcv3, 2.1 million more than in 2020 and 5.9 million more than in 2019. In 2021, the number of infants who did not receive any DTPcv dose by age 12 months (18.2 million) was 37% higher than in 2019 (13.3 million). Coverage with the first dose of measles-containing vaccine (MCV1) decreased from an average of 85% during 2015-2019 to 84% in 2020 and 81% in 2021. These are the lowest coverage levels for DTPcv3 and MCV1 since 2008. ​Global coverage estimates were also lower in 2021 than in 2020 and 2019 for bacillus Calmette-Guérin vaccine (BCG) as well as for the completed series of Haemophilus influenzae type b vaccine (Hib), hepatitis B vaccine (HepB), polio vaccine (Pol), and rubella-containing vaccine (RCV). The COVID-19 pandemic has resulted in disruptions to routine immunization services worldwide. Full recovery to immunization programs will require context-specific strategies to address immunization gaps by catching up missed children, prioritizing essential health services, and strengthening immunization programs to prevent outbreaks (3).

Association between childhood immunisation coverage and proximity to health facilities in rural settings: a cross-sectional analysis of Service Provision Assessment 2013-2014 facility data and Demographic and Health Survey 2015-2016 individual data in Malawi

OBJECTIVES

Despite significant progress in childhood vaccination coverage globally, substantial inequality remains. Remote rural populations are recognised as a priority group for immunisation service equity. We aimed to link facility and individual data to examine the relationship between distance to services and immunisation coverage empirically, specifically using a rural population.

DESIGN AND SETTING

Retrospective cross-sectional analysis of facility data from the 2013-2014 Malawi Service Provision Assessment and individual data from the 2015-2016 Malawi Demographic and Health Survey, linking children to facilities within a 5 km radius. We examined associations between proximity to health facilities and vaccination receipt via bivariate comparisons and logistic regression models.

PARTICIPANTS

2740 children aged 12-23 months living in rural areas.

OUTCOME MEASURES

Immunisation coverage for the six vaccines included in the Malawi Expanded Programme on Immunization schedule for children under 1 year at time of study, as well as two composite vaccination indicators (receipt of basic vaccines and receipt of all recommended vaccines), zero-dose pentavalent coverage, and pentavalent dropout.

FINDINGS

72% (706/977) of facilities offered childhood vaccination services. Among children in rural areas, 61% were proximal to (within 5 km of) a vaccine-providing facility. Proximity to a vaccine-providing health facility was associated with increased likelihood of having received the rotavirus vaccine (93% vs 88%, p=0.004) and measles vaccine (93% vs 89%, p=0.01) in bivariate tests. In adjusted comparisons, how close a child was to a health facility remained meaningfully associated with how likely they were to have received rotavirus vaccine (adjusted OR (AOR) 1.63, 95% CI 1.13 to 2.33) and measles vaccine (AOR 1.62, 95% CI 1.11 to 2.37).

CONCLUSION

Proximity to health facilities was significantly associated with likelihood of receipt for some, but not all, vaccines. Our findings reiterate the vulnerability of children residing far from static vaccination services; efforts that specifically target remote rural populations living far from health facilities are warranted to ensure equitable vaccination coverage.

Economic-Related Inequalities in Zero-Dose Children: A Study of Non-Receipt of Diphtheria-Tetanus-Pertussis Immunization Using Household Health Survey Data from 89 Low- and Middle-Income Countries

Despite advances in scaling up new vaccines in low- and middle-income countries, the global number of unvaccinated children has remained high over the past decade. We used 2000–2019 household survey data from 154 surveys representing 89 low- and middle-income countries to assess within-country, economic-related inequality in the prevalence of one-year-old children with zero doses of diphtheria–tetanus–pertussis (DTP) vaccine. Zero-dose DTP prevalence data were disaggregated by household wealth quintile. Difference, ratio, slope index of inequality, concentration index, and excess change measures were calculated to assess the latest situation and change over time, by country income grouping for 17 countries with high zero-dose DTP numbers and prevalence. Across 89 countries, the median prevalence of zero-dose DTP was 7.6%. Within-country inequalities mostly favored the richest quintile, with 19 of 89 countries reporting a rich–poor gap of ≥20.0 percentage points. Low-income countries had higher inequality than lower–middle-income countries and upper–middle-income countries (difference between the median prevalence in the poorest and richest quintiles: 14.4, 8.9, and 2.7 percentage points, respectively). Zero-dose DTP prevalence among the poorest households of low-income countries declined between 2000 and 2009 and between 2010 and 2019, yet economic-related inequality remained high in many countries. Widespread economic-related inequalities in zero-dose DTP prevalence are particularly pronounced in low-income countries and have remained high over the previous decade.

Impact of the SARS-CoV-2 pandemic on vaccine-preventable disease campaigns

BACKGROUND

The COVID-19 pandemic has contributed to the widespread disruption of immunization services, including the postponement of mass vaccination campaigns.

METHODS

In May 2020, the World Health Organization (WHO) and partners started monitoring COVID-19-related disruptions to mass vaccination campaigns against cholera, measles, meningitis A, polio, tetanus-diphtheria, typhoid and yellow fever through the Immunization Repository Campaign Delay Tracker. The authors reviewed the number and target population of reported preventive and outbreak response vaccination campaigns scheduled, postponed, canceled and reinstated, at four time-points: May 2020, December 2020, May 2021 and December 2021.

FINDINGS

Mass vaccination campaigns across all vaccines were disrupted heavily by COVID-19. In May 2020, 105 of 183 (57%) campaigns were postponed or canceled in 57 countries due to COVID-19, with an estimated 796 million postponed or missed vaccine doses. Campaign resumption was observed beginning in July 2020. In December 2021, 77 of 472 (16%) campaigns in 54 countries, mainly in the African Region, were still postponed or canceled due to COVID-19, with about 382 million postponed or missed vaccine doses.

INTERPRETATION

There is likely high risk of vaccine-preventable disease outbreaks due to an increased number of susceptible persons resulting from the large-scale mass vaccination campaign postponement caused by COVID-19 across all regions.

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.

Impact of the SARS-CoV-2 pandemic on routine immunisation services: evidence of disruption and recovery from 170 countries and territories

Background

The SARS-CoV-2 pandemic has revealed the vulnerability of immunisation systems worldwide, although the scale of these disruptions has not been described at a global level. This study aims to assess the impact of COVID-19 on routine immunisation using triangulated data from global, country-based, and individual-reported sources obtained during the pandemic period.

Methods

This report synthesised data from 170 countries and territories. Data sources included administered vaccine-dose data from January to December, 2019, and January to December, 2020, WHO regional office reports, and a WHO-led pulse survey administered in April, 2020, and June, 2020. Results were expressed as frequencies and proportions of respondents or reporting countries. Data on vaccine doses administered were weighted by the population of surviving infants per country.

Findings

A decline in the number of administered doses of diphtheria–pertussis–tetanus-containing vaccine (DTP3) and first dose of measles-containing vaccine (MCV1) in the first half of 2020 was noted. The lowest number of vaccine doses administered was observed in April, 2020, when 33% fewer DTP3 doses were administered globally, ranging from 9% in the WHO African region to 57% in the South-East Asia region. Recovery of vaccinations began by June, 2020, and continued into late 2020. WHO regional offices reported substantial disruption to routine vaccination sessions in April, 2020, related to interrupted vaccination demand and supply, including reduced availability of the health workforce. Pulse survey analysis revealed that 45 (69%) of 65 countries showed disruption in outreach services compared with 27 (44%) of 62 countries with disrupted fixed-post immunisation services.

Interpretation

The marked magnitude and global scale of immunisation disruption evokes the dangers of vaccine-preventable disease outbreaks in the future. Trends indicating partial resumption of services highlight the urgent need for ongoing assessment of recovery, catch-up vaccination strategy implementation for vulnerable populations, and ensuring vaccine coverage equity and health system resilience.

Funding

US Agency for International Development.

Data quality of reported child immunization coverage in 194 countries between 2000 and 2019

Analyzing immunization coverage data is crucial to guide decision-making in national immunization programs and monitor global initiatives such as the Immunization Agenda 2030. We aimed to assess the quality of reported child immunization coverage data for 194 countries over 20 years. We analyzed child immunization coverage as reported to the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) between 2000-2019 by all WHO Member States for Bacillus Calmette-Guérin (BCG) vaccine birth dose, first and third doses of diphtheria-tetanus-pertussis-containing vaccine (DTP1, DTP3), and first dose of measles-containing vaccine (MCV1). We assessed completeness, consistency, integrity, and congruence and assigned data quality flags in case anomalies were detected. Generalized linear mixed-effects models were used to estimate the probability of flags worldwide and for different country groups over time. The probability of data quality flags was 18.2% globally (95% confidence interval [CI] 14.8-22.3). The lowest probability was seen in South-East Asia (6.3%, 3.3-11.8, p = 0.002), the highest in the Americas (29.7%, 22.7-37.9, p < 0.001). The probability of data quality flags declined by 5.1% per year globally (3.2-7.0, p < 0.001). The steepest decline was seen in Africa (-9.6%, -13.0 to -5.8, p < 0.001), followed by Europe (-5.4%, -9.2 to -1.6, p = 0.0055), and the Americas (-4.9%, -9.2 to -0.6, p = 0.026). Most country groups showed a statistically significant decline, and none had a statistically significant increase. Over the past two decades, the quality of global immunization coverage data appears to have improved. However, progress has not been universal. The results highlight the need for joint efforts so that all countries collect, report, and use high-quality data for action in immunization.

Subnational inequalities in diphtheria-tetanus-pertussis immunization in 24 countries in the African Region

OBJECTIVE

To analyse subnational inequality in diphtheria-tetanus-pertussis (DTP) immunization dropout in 24 African countries using administrative data on receipt of the first and third vaccine doses (DTP1 and DTP3, respectively) collected by the Joint Reporting Process of the World Health Organization and the United Nations Children's Fund.

METHODS

Districts in each country were grouped into quintiles according to the proportion of children who dropped out between DTP1 and DTP3 (i.e. the dropout rate). We used six summary measures to quantify inequalities in dropout rates between districts and compared rates with national dropout rates and DTP1 and DTP3 immunization coverage.

FINDINGS

The median dropout rate across countries was 2.4% in quintiles with the lowest rate and 14.6% in quintiles with the highest rate. In eight countries, the difference between the highest and lowest quintiles was 14.9 percentage points or more. In most countries, underperforming districts in the quintile with the highest rate tended to lag disproportionately behind the others. This divergence was not evident from looking only at national dropout rates. Countries with the largest inequalities in absolute subnational dropout rate tended to have lower estimated national DTP1 and DTP3 immunization coverage.

CONCLUSION

There were marked inequalities in DTP immunization dropout rates between districts in most countries studied. Monitoring dropout at the subnational level could help guide immunization interventions that address inequalities in underserved areas, thereby improving overall DTP3 coverage. The quality of administrative data should be improved to ensure accurate and timely assessment of geographical inequalities in immunization.

Estimating global and regional disruptions to routine childhood vaccine coverage during the COVID-19 pandemic in 2020: a modelling study

BACKGROUND

The COVID-19 pandemic and efforts to reduce SARS-CoV-2 transmission substantially affected health services worldwide. To better understand the impact of the pandemic on childhood routine immunisation, we estimated disruptions in vaccine coverage associated with the pandemic in 2020, globally and by Global Burden of Disease (GBD) super-region.

METHODS

For this analysis we used a two-step hierarchical random spline modelling approach to estimate global and regional disruptions to routine immunisation using administrative data and reports from electronic immunisation systems, with mobility data as a model input. Paired with estimates of vaccine coverage expected in the absence of COVID-19, which were derived from vaccine coverage models from GBD 2020, Release 1 (GBD 2020 R1), we estimated the number of children who missed routinely delivered doses of the third-dose diphtheria-tetanus-pertussis (DTP3) vaccine and first-dose measles-containing vaccine (MCV1) in 2020.

FINDINGS

Globally, in 2020, estimated vaccine coverage was 76·7% (95% uncertainty interval 74·3-78·6) for DTP3 and 78·9% (74·8-81·9) for MCV1, representing relative reductions of 7·7% (6·0-10·1) for DTP3 and 7·9% (5·2-11·7) for MCV1, compared to expected doses delivered in the absence of the COVID-19 pandemic. From January to December, 2020, we estimated that 30·0 million (27·6-33·1) children missed doses of DTP3 and 27·2 million (23·4-32·5) children missed MCV1 doses. Compared to expected gaps in coverage for eligible children in 2020, these estimates represented an additional 8·5 million (6·5-11·6) children not routinely vaccinated with DTP3 and an additional 8·9 million (5·7-13·7) children not routinely vaccinated with MCV1 attributable to the COVID-19 pandemic. Globally, monthly disruptions were highest in April, 2020, across all GBD super-regions, with 4·6 million (4·0-5·4) children missing doses of DTP3 and 4·4 million (3·7-5·2) children missing doses of MCV1. Every GBD super-region saw reductions in vaccine coverage in March and April, with the most severe annual impacts in north Africa and the Middle East, south Asia, and Latin America and the Caribbean. We estimated the lowest annual reductions in vaccine delivery in sub-Saharan Africa, where disruptions remained minimal throughout the year. For some super-regions, including southeast Asia, east Asia, and Oceania for both DTP3 and MCV1, the high-income super-region for DTP3, and south Asia for MCV1, estimates suggest that monthly doses were delivered at or above expected levels during the second half of 2020.

INTERPRETATION

Routine immunisation services faced stark challenges in 2020, with the COVID-19 pandemic causing the most widespread and largest global disruption in recent history. Although the latest coverage trajectories point towards recovery in some regions, a combination of lagging catch-up immunisation services, continued SARS-CoV-2 transmission, and persistent gaps in vaccine coverage before the pandemic still left millions of children under-vaccinated or unvaccinated against preventable diseases at the end of 2020, and these gaps are likely to extend throughout 2021. Strengthening routine immunisation data systems and efforts to target resources and outreach will be essential to minimise the risk of vaccine-preventable disease outbreaks, reach children who missed routine vaccine doses during the pandemic, and accelerate progress towards higher and more equitable vaccination coverage over the next decade.

FUNDING

Bill & Melinda Gates Foundation.

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.

Compliance of WHO and UNICEF estimates of national immunization coverage (WUENIC) with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) criteria

Background: The objective of the study was to assess compliance of the WHO and UNICEF estimates of national immunization coverage (WUENIC) against the 18 criteria of the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) that define and promote good practice in reporting of global health estimates. Methods: We conducted a desk review of the WUENIC estimation and reporting process vis-à-vis each of the 18 GATHER criteria to complete a self-assessment of compliance with GATHER. Results: Overall, WUENIC estimates are fully compliant with 17 of the GATHER criteria and partially compliant with one criterion-criterion 11, which is related to candidate model evaluation and final model selection. Conclusion: The GATHER criteria provide a useful framework for documenting WUENIC's compliance with contemporary reporting requirements. Given the role of vaccination coverage estimates in global monitoring and guiding disease control efforts, WHO and UNICEF strive to produce and publish robust estimates of vaccination coverage through a transparent process that emphasizes country involvement.

Pairs of independent nationally representative vaccination coverage surveys conducted within one year of each other: A global overview covering 2000-2019

Background

Population-based surveys play an important role in measuring vaccination coverage. Surveys measuring vaccination coverage may be commissioned by the Expanded Programme on Immunization (EPI surveys) or part of multi-domain non-EPI surveys such as Demographic and Health Surveys (DHS) or Multiple Indicator Cluster Surveys (MICS). Surveys conducted too close in time to each other may not only be an inefficient use of resources but may also create problems for programme staff when results suggest inconsistent patterns of programme performance for similar time periods.

Objective

To summarize the occurrence of vaccination coverage surveys conducted close in time during 2000–2019 and compare results of EPI and non-EPI coverage surveys when the surveys were conducted within one year of each other.

Methods

Using a database of published national-level vaccination coverage survey results compiled by the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF), the authors abstracted information on survey field work dates, sample size, percentage of children with documented history of vaccination and the percent coverage, as well as published uncertainty intervals from DHS and MICS, for the first and third doses of diphtheria-tetanus toxoid-pertussis containing vaccine (DTP1, DTP3) and first dose of measles containing vaccine (MCV1). Survey results of EPI and non-EPI surveys were compared.

Results

The authors identified 646 surveys with final reports and estimates of national-level vaccination coverage for DTP1, DTP3, or MCV1 from a total of 687 surveys with data collection start date from 2000 to 2019. Of the 140 countries with at least one vaccination coverage survey, a median of four surveys was observed. Most countries were Gavi-eligible and located in the WHO Africa Region. Sixty-six survey dyads were identified where an EPI survey occurred within one year of a non-EPI survey. For the 66 dyads, in 49 of 59 with information available, EPI surveys reported higher proportion of documented evidence of vaccination and EPI survey results tended to suggest higher levels of vaccination coverage compared to the non-EPI surveys; quite often, differences were substantial. Surveys that found higher proportions of children with documented vaccination evidence tended to also find higher proportions of children who had been vaccinated.

Summary

Opportunities exist to improve overall planning of vaccination coverage measurement in population-based household surveys so that both EPI and non-EPI surveys are more comparable and survey coverage estimates are more appropriately spaced in time. When surveys occur too close in time, careful attention is warranted to ensure comparability and assess sources of documented evidence of vaccination and related coverage differences.

Characterization of immunization secondary analyses using demographic and health surveys (DHS) and multiple indicator cluster surveys (MICS), 2006-2018

BACKGROUND

Infant immunization coverage worldwide has plateaued at about 85%. Using existing survey data to conduct analyses beyond estimating coverage may help immunization programmes better tailor strategies to reach un- and under-immunized children. The Demographic and Health Survey (DHS) and the Multiple Indicators Cluster Survey (MICS), routinely conducted in low and middle-income countries (LMICs), collect immunization data, yet vaccination coverage is often the only indicator reported and used. We conducted a review of published immunization-related analyses to characterize and quantify immunization secondary analyses done using DHS and MICS databases.

METHODS

We conducted a systematic search of the literature, of immunization-related secondary analyses from DHS or MICS published between 2006 and August 2018. We searched 15 electronic databases without language restrictions. For the articles included, relevant information was extracted and analyzed to summarize the characteristics of immunization-related secondary analyses. Results are presented following the PRISMA guidelines.

RESULTS

Among 1411 papers identified, 115 met our eligibility criteria; additionally, one article was supplemented by the Pan American Health Organization. The majority were published since 2012 (77.6%), and most (68.9%) had a first or corresponding author affiliated with institutions in high-income countries (as opposed to LMICs where these surveys are conducted). The median delay between survey implementation and publication of the secondary analysis was 5.4 years, with papers with authors affiliated to institutions in LMIC having a longer median publication delay (p < 0.001). Over 80% of the published analyses looked at factors associated with a specific vaccine or with full immunization. Quality proxies, such as reporting percent of immunization data from cards vs recall; occurrence and handling of missing data; whether survey analyses were weighted; and listing of potential biases or limitations of the original survey or analyses, were infrequently mentioned.

CONCLUSION

Our review suggests that more needs to be done to increase the increase the utilization of existing DHS and MICS datasets and improve the quality of the analyses to inform immunization programmes. This would include increasing the proportion of analyses done in LMICs, reducing the time lag between survey implementation and publication of additional analyses, and including more qualitative information about the survey in the publications to better interpret the results.

Combining cluster surveys to estimate vaccination coverage: Experiences from Nigeria's multiple indicator cluster survey / national immunization coverage survey (MICS/NICS), 2016-17

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Nigeria's immunization stakeholders cooperated on the 2016–17 MICS/NICS survey.

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Extra survey clusters were added in 20 states to improve outcome precision.

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Data from MICS & supplementary clusters were pooled after passing a statistical test.

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Combined results were used to guide policy, but not as precise as originally hoped.

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We explore organizational aspects of cooperation & technical aspects of pooled data.

In 2015 immunization stakeholders in Nigeria were proceeding with plans that would have fielded two nationally representative surveys to estimate vaccination coverage at the same time. Rather than duplicate efforts and generate either conflicting or redundant results, the stakeholders collaborated to conduct a combined Multiple Indicator Cluster Survey (MICS) / National Immunization Coverage Survey (NICS) with MICS focusing on core sampling clusters and NICS adding supplementary clusters in 20 states, to improve precision of outcomes there. This paper describes the organizational and technical aspects of that collaboration, including details on design of the sample supplement and analysis of the pooled dataset. While complicated, the collaboration was successful; it yielded a unified set of relevant coverage estimates and fostered some novel sub-national results dissemination work.

Factors limiting data quality in the expanded programme on immunization in low and middle-income countries: A scoping review

Few public health interventions can match the immense achievements of immunization in terms of mortality and morbidity reduction. However, progress in reaching global coverage goals and achieving universal immunization coverage have stalled; with key stakeholders concerned about the accuracy of reported coverage figures. Incomplete and incorrect data has made it challenging to obtain an accurate overview of immunization coverage, particularly in low- and middle-income countries (LMIC). To date, only one literature review concerning immunization data quality exists. However, it only included articles from Gavi-eligible countries, did not go deep into the characteristics of the data quality problems, and used a narrow 'data quality' definition. This scoping review builds upon that work; exploring the "state of data quality" in LMIC, factors affecting data quality in these settings and potential means to improve it. Only a small volume of literature addressing immunization data quality in LMIC was found and definitions of 'data quality' varied widely. Data quality was, on the whole, considered poor in the articles included. Coverage numerators were seen to be inflated for official reports and denominators were inaccurate and infrequently adjusted. Numerous factors related to these deficiencies were reported, including health information system fragmentation, overreliance on targets and poor data management processes. Factors associated with health workers were noted most frequently. Authors suggested that data quality could be improved by ensuring proper data collection tools, increasing workers' capacities and motivation through training and supervision, whilst also ensuring adequate and timely feedback on the data collected. The findings of this scoping review can serve as the basis to identify and address barriers to good quality immunization data in LMICs. Overcoming said barriers is essential if immunization's historic successes are to continue.

A systematic review of the agreement of recall, home-based records, facility records, BCG scar, and serology for ascertaining vaccination status in low and middle-income countries

Background: Household survey data are frequently used to estimate vaccination coverage - a key indicator for monitoring and guiding immunization programs - in low and middle-income countries. Surveys typically rely on documented evidence from home-based records (HBR) and/or maternal recall to determine a child's vaccination history, and may also include health facility sources, BCG scars, and/or serological data. However, there is no gold standard source for vaccination history and the accuracy of existing sources has been called into question. Methods and Findings: We conducted a systematic review of literature published January 1, 1975 through December 11, 2017 that compared vaccination status at the child-level from at least two sources of vaccination history. 27 articles met inclusion criteria. The percentage point difference in coverage estimates varied substantially when comparing caregiver recall to HBRs (median: +1, range: -43 to +17), to health facility records (median: +5, range: -29 to +34) and to serology (median: -20, range: -32 to +2). Ranges were also wide comparing HBRs to facility-based records (median: +17, range: -61 to +21) and to serology (median: +2, range: -38 to +36). Across 10 studies comparing recall to HBRs, Kappa values exceeded 0.60 in 45% of comparisons; across 7 studies comparing recall to facility-based records, Kappa never reached 0.60. Agreement varied depending on study setting, coverage level, antigen type, number of doses, and child age. Conclusions: Recall and HBR provide relatively concordant vaccination histories in some settings, but both have poor agreement with facility-based records and serology. Long-term, improving clinical decision making and vaccination coverage estimates will depend on strengthening administrative systems and record keeping practices. Short-term, there must be greater recognition of imperfections across available vaccination history sources and explicit clarity regarding survey goals and the level of precision, potential biases, and associated resources needed to achieve these goals.

Geospatial variation in measles vaccine coverage through routine and campaign strategies in Nigeria: Analysis of recent household surveys

Measles vaccination campaigns are conducted regularly in many low- and middle-income countries to boost measles control efforts and accelerate progress towards elimination. National and sometimes first-level administrative division campaign coverage may be estimated through post-campaign coverage surveys (PCCS). However, these large-area estimates mask significant geographic inequities in coverage at more granular levels. Here, we undertake a geospatial analysis of the Nigeria 2017-18 PCCS data to produce coverage estimates at 1 × 1 km resolution and the district level using binomial spatial regression models built on a suite of geospatial covariates and implemented in a Bayesian framework via the INLA-SPDE approach. We investigate the individual and combined performance of the campaign and routine immunization (RI) by mapping various indicators of coverage for children aged 9-59 months. Additionally, we compare estimated coverage before the campaign at 1 × 1 km and the district level with predicted coverage maps produced using other surveys conducted in 2013 and 2016-17. Coverage during the campaign was generally higher and more homogeneous than RI coverage but geospatial differences in the campaign's reach of previously unvaccinated children are shown. Persistent areas of low coverage highlight the need for improved RI performance. The results can help to guide the conduct of future campaigns, improve vaccination monitoring and measles elimination efforts. Moreover, the approaches used here can be readily extended to other countries.

A systematic review of the agreement of recall, home-based records, facility records, BCG scar, and serology for ascertaining vaccination status in low and middle-income countries

Background: Household survey data are frequently used to estimate vaccination coverage - a key indicator for monitoring and guiding immunization programs - in low and middle-income countries. Surveys typically rely on documented evidence from home-based records (HBR) and/or maternal recall to determine a child’s vaccination history, and may also include health facility sources, BCG scars, and/or serological data. However, there is no gold standard source for vaccination history and the accuracy of existing sources has been called into question.

Methods and Findings: We conducted a systematic review of literature published January 1, 1975 through December 11, 2017 that compared vaccination status at the child-level from at least two sources of vaccination history. 27 articles met inclusion criteria. The percentage point difference in coverage estimates varied substantially when comparing caregiver recall to HBRs (median: +1, range: -43 to +17), to health facility records (median: +5, range: -29 to +34) and to serology (median: -20, range: -32 to +2). Ranges were also wide comparing HBRs to facility-based records (median: +17, range: -61 to +21) and to serology (median: +2, range: -38 to +36). Across 10 studies comparing recall to HBRs, Kappa values exceeded 0.60 in 45% of comparisons; across 7 studies comparing recall to facility-based records, Kappa never reached 0.60. Agreement varied depending on study setting, coverage level, antigen type, number of doses, and child age.

Conclusions: Recall and HBR provide relatively concordant vaccination histories in some settings, but both have poor agreement with facility-based records and serology. Long-term, improving clinical decision making and vaccination coverage estimates will depend on strengthening administrative systems and record keeping practices. Short-term, there must be greater recognition of imperfections across available vaccination history sources and explicit clarity regarding survey goals and the level of precision, potential biases, and associated resources needed to achieve these goals.

Delayed second dose of oral cholera vaccine administered before high-risk period for cholera transmission: Cholera control strategy in Lusaka, 2016

BACKGROUND

In April 2016, an emergency vaccination campaign using one dose of Oral Cholera Vaccine (OCV) was organized in response to a cholera outbreak that started in Lusaka in February 2016. In December 2016, a second round of vaccination was conducted, with the objective of increasing the duration of protection, before the high-risk period for cholera transmission. We assessed vaccination coverage for the first and second rounds of the OCV campaign.

METHODS

Vaccination coverage was estimated after each round from a sample selected from targeted-areas for vaccination using a cross-sectional survey in to establish the vaccination status of the individuals recruited. The study population included all individuals older than 12 months residing in the areas targeted for vaccination. We interviewed 505 randomly selected individuals after the first round and 442 after the second round. Vaccination status was ascertained either by vaccination card or verbal reporting. Households were selected using spatial random sampling.

RESULTS

The vaccination coverage with two doses was 58.1% (25/43; 95%CI: 42.1-72.9) in children 1-5 years old, 59.5% (69/116; 95%CI: 49.9-68.5) in children 5-15 years old and 19.9% (56/281; 95%CI: 15.4-25.1) in adults above 15 years old. The overall dropout rate was 10.9% (95%CI: 8.1-14.1). Overall, 69.9% (n = 309/442; 95%CI: 65.4-74.1) reported to have received at least one OCV dose.

CONCLUSIONS

The areas at highest risk of suffering cholera outbreaks were targeted for vaccination obtaining relatively high vaccine coverage after each round. However, the long delay between doses in areas subject to considerable population movement resulted in many individuals receiving only one OCV dose. Additional vaccination campaigns may be required to sustain protection over time in case of persistence of risk. Further evidence is needed to establish a maximum optimal interval time of a delayed second dose and variations in different settings.

Assessing the quality and accuracy of national immunization program reported target population estimates from 2000 to 2016

Background

A common means of vaccination coverage measurement is the administrative method, done by dividing the aggregated number of doses administered over a set period (numerator) by the target population (denominator). To assess the quality of national target populations, we defined nine potential denominator data inconsistencies or flags that would warrant further exploration and examination of data reported by Member States to the World Health Organization (WHO) and UNICEF between 2000 and 2016.

Methods and findings

We used the denominator reported to calculate national coverage for BCG, a tuberculosis vaccine, and for the third dose of diphtheria-tetanus-pertussis-containing (DTP3) vaccines, usually live births (LB) and surviving infants (SI), respectively. Out of 2,565 possible reporting events (data points for countries using administrative coverage with the vaccine in the schedule and year) for BCG and 2,939 possible reporting events for DTP3, 194 and 274 reporting events were missing, respectively. Reported coverage exceeding 100% was seen in 11% of all reporting events for BCG and in 6% for DTP3. Of all year-to-year percent differences in reported denominators, 12% and 11% exceeded 10% for reported LB and SI, respectively. The implied infant mortality rate, based on the country’s reported LB and SI, would be negative in 9% of all reporting events i.e., the country reported more SI than LB for the same year. Overall, reported LB and SI tended to be lower than the UN Population Division 2017 estimates, which would lead to overestimation of coverage, but this difference seems to be decreasing over time. Other inconsistencies were identified using the nine proposed criteria.

Conclusions

Applying a set of criteria to assess reported target populations used to estimate administrative vaccination coverage can flag potential quality issues related to the national denominators and may be useful to help monitor ongoing efforts to improve the quality of vaccination coverage estimates.

Home-based records' quality and validity of caregivers' recall of children's vaccination in Lebanon

INTRODUCTION

Home-based records (HBRs) (also known as vaccination cards) and caregivers' recall are the main means to ascertain vaccination status; however, data on the quality of HBRs and the validity of recall vaccination data compared to HBRs is scarce. This manuscript presents results from two analyses related to HBRs, one on HBR pictures taken during a vaccination coverage survey, including an assessment of the HBR quality and legibility, and an evaluation of the agreement between caregivers' recall and the vaccination information in the HBRs.

METHODS

Using pictures from 500 randomly selected HBRs collected during the 2016 district-based immunization coverage evaluation survey in Lebanon, two independent researchers assessed the quality of the picture and then of the HBR itself against a pre-defined set of criteria. HBRs were classified into three types: private, public and all others. In addition, caregivers' recall was compared to data found in vaccination HBRs to assess measures of vaccination status agreement for 5713 children for whom both sources of data were available.

RESULTS

Over 90% of the 500 HBR pictures reviewed were considered adequate to assess the HBR quality. In the sample, most cards were type 1 (41%), followed by type 2 (34%). Most HBRs met the set criteria for quality in terms of physical condition and legibility, while, among the 28 different types of cards, vaccination cards' content and design met a moderate level of quality. Concordance, sensitivity, specificity, positive and negative predictive values, and the Kappa statistic showed diverse levels of agreement for vaccination status per vaccine dose between caregivers' recall and vaccination HBRs.

CONCLUSION

This study illustrates that taking pictures of HBRs in a coverage survey is feasible and useful to conduct secondary analyses related to HBRs, such as assessing their quality and comparing recall with HBRs when both sources of data are available.

MMR2 vaccination coverage and timeliness among children born in 2004 - 2009: a national survey in Saint Lucia, 2015

Objectives

To more accurately determine coverage and timeliness of the second dose of measles-mumps-rubella vaccine (MMR2), while identifying factors associated with low MMR2 vaccination uptake among children in Saint Lucia.

Methods

A survey was conducted in October - November 2015 targeting children born in 2004 - 2009. At 86 preschools and primary schools, two children from each grade were randomly selected, yielding an effective sample of 836 children. Health records were reviewed to assess vaccination coverage and timeliness. Parents and/or guardians and principals of all 86 schools were interviewed regarding knowledge, attitudes, and practices related to vaccination.

Results

Of 767 children included, 75% were vaccinated with MMR2 (n = 572); 46.7% were vaccinated in a timely manner, i.e., by 5 years of age. Cohorts born in 2004, 2005, and 2008 reported the lowest proportion. 'Mothers as caregivers' was positively associated with timely MMR2 vaccination. Although 97% of principals surveyed considered vaccination important, 48.8% were not aware of national legislation requiring complete vaccination prior to school entry. Survey results concurred with the low MMR2 administrative coverage rates reported by Saint Lucia, much lower than the recommended 95%.

Conclusions

Based on the results of this survey, Saint Lucia's national immunization program has lowered the age of MMR2 to 18 months in 2016, increased advocacy with schools to enforce the school-entry law, and is working to vaccinate the cohorts of children who have not received timely MMR2.

Assessing electronic immunization registries: the Pan American Health Organization experience

Objective.

To develop a methodology to assess electronic immunization registries (EIRs) in low- and middle-income countries (LMICs) in Latin America and the Caribbean.

Methods.

A team from the Immunization Unit at the Pan American Health Organization (PAHO) reviewed existing methodologies to evaluate health information systems, particularly the Performance of Routine Information System Management (PRISM) framework and methodologies used to assess information systems. In 2014, the PAHO team convened a small working group to develop an evaluation approach to be added to the existing World Health Organization immunization data quality self-assessment (DQS) tool. The resulting DQS with an added EIR component was named “DQS Plus.” The DQS Plus methodology was used in Panama in May 2014 and in Honduras in November 2015.

Results.

The DQS Plus tool proved feasible and easy to implement in Panama and Honduras, including by not adding much time or resources to those needed for a usual DQS. The information obtained from the DQS Plus assessment was practical and helped provide health authorities with recommendations to update and improve their EIR, strengthen the use of the registry, and enhance the data the assessment produced, at all levels of the health system. These recommendations are currently being implemented in the two countries.

Conclusions.

The DQS Plus proved to be a practical and useful approach for assessing an EIR in an LMIC and generating actionable recommendations. Further work on defining operational and related EIR functional standards in LMICs will help develop an improved EIR assessment tool for Latin America and the Caribbean, and potentially elsewhere.

Vaccination coverage in Lebanon following the Syrian crisis: results from the district-based immunization coverage evaluation survey 2016

Background

Following the Syrian crisis, a substantial influx of Syrian refugees into Lebanon posed new challenges to optimal vaccination coverage for all children residing in the country. In 2016, the district-based immunization coverage evaluation survey (CES) assessed routine immunization coverage at the district level in Lebanon among children aged 12–59 months.

Methods

A cross-sectional multistage cluster survey was conducted in all of Lebanon (with the exception of the Nabatieh district) using the World Health Organization (WHO) recommended Expanded Programme on Immunization (EPI) methodology adapted to the local context. A survey questionnaire consisting of closed and open-ended questions concerning demographic information and the child’s immunization status was administered to collect immunization status information.

Results

Among surveyed children aged 12–59 months, irrespective of nationality, vaccination coverage at the national level for any recommended last dose was below the targeted 95%. Generally, vaccination coverage levels increased with age and were higher among Lebanese than Syrian children. However, large variations were revealed when coverage rates were analyzed at the district level. Vaccination was significantly associated with nationality, age, mother’s educational status and the place of vaccination. Common reasons for undervaccination included the child’s illness at the time of vaccine administration, vaccination fees, lack of awareness or a doctor’s advice not to vaccinate during campaigns.

Conclusions

Substantial variability exists in vaccination coverage among children aged 12–59 months residing in different districts in Lebanon. Immunization coverage reached 90% or above only for the first doses of polio and pentavalent vaccines. A considerable dropout rate from the first dose of any vaccine is observed. Efforts to optimize coverage levels should include increased vaccination initiatives targeting both refugee children and children from vulnerable host communities, increased cooperation between public and private vaccine providers, improved training for vaccine providers to adhere to complete vaccine administration recommendations, and increased awareness among caregivers.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6418-9) contains supplementary material, which is available to authorized users.

Factors affecting age-appropriate timeliness of vaccination coverage among children in Lebanon

Background: The effect of immunization does not only depend on its completeness, but also on its timely administration. Routine childhood vaccinations schedules recommend that children receive the vaccine doses at specific ages. This article attempts to assess timeliness of routine vaccination coverage among a sub-sample of children from a survey conducted in 2016. Methods: This analysis was based on data from a cross-sectional multistage cluster survey conducted between December 2015 and June 2016 among caregivers of children aged 12-59 months in all of Lebanon using a structured survey questionnaire. The analysis used Kaplan-Meier curves and logistic regression to identify the predictors of age-appropriate immunization. Results: Among the 493 randomly selected children, timely administration of the third dose of polio vaccine, diphtheria-tetanus-pertussis (DTP)-containing vaccine and hepatitis B (HepB) vaccine occurred in about one-quarter of children. About two-thirds of children received the second dose of a measles-containing vaccine (MCV) within the age interval recommended by the Expanded Programme on Immunization (EPI). Several factors including socio-demographic, knowledge, beliefs and practices were found to be associated with age-appropriate vaccination; however, this association differed between the types and doses of vaccine. Important factors associated with timely vaccination included being Lebanese as opposed to Syrian and being born in a hospital for hepatitis B birth dose; believing that vaccination status was up-to-date was related to untimely vaccination. Conclusions: The results suggest that there is reason for concern over the timeliness of vaccination in Lebanon. Special efforts need to be directed towards the inclusion of timeliness of vaccination as another indicator of the performance of the EPI in Lebanon.

Improving immunization data quality in Peru and Mexico: Two case studies highlighting challenges and lessons learned

INTRODUCTION

The Global Vaccine Action Plan and the Regional Immunization Action Plan of the Americas call for countries to improve immunization data quality. Immunization information systems, particularly electronic immunization registries (EIRs), can help to facilitate program management and increase coverage. However, little is known about efforts to develop and implement such systems in low- and middle-income countries. We present the experiences of Mexico and Peru in implementing EIRs.

METHODS

We conducted case studies of an EIR in Mexico and of a population registry in Peru. Information was gathered from technical documents, stakeholder focus groups, site visits, and semi-structured interviews of national stakeholders. We organized findings into narratives that emphasized challenges and lessons learned.

RESULTS

Mexico built one of the world's first EIRs, incorporating novel features such as local-level tracking of patients; however, insufficient resources and poor data registration practices led to the system's discontinuation. Peru created an information system to improve affiliation to social programs, including the immunization program and quality of demographic data. Mexico's experience highlights lessons in failed sustainability of an EIR and a laudable effort to reform a country's information system. Peru's demonstrates that attempts to improve health and other data may strengthen health systems, including immunization data. Major challenges in information system implementation and sustainability in Peru and Mexico related to funding, clear governance structures, and resistance among health workers.

DISCUSSION

These case studies reinforce the need for countries to ensure adequate funding, plans for sustainability, and health worker capacity-building activities before implementing EIRs. They also suggest new approaches to implementation, including economic incentives for sub-national administrative levels and opportunities to link efforts to improve immunization data with other health and political priorities. More information on best practices is needed to ensure the successful adoption and sustainability of immunization registries in low- and middle-income countries.

Collecting and using reliable vaccination coverage survey estimates: Summary and recommendations from the "Meeting to share lessons learnt from the roll-out of the updated WHO Vaccination Coverage Cluster Survey Reference Manual and to set an operational research agenda around vaccination coverage surveys", Geneva, 18-21 April 2017

Household surveys are frequently used as means of vaccination coverage measurement, but obtaining accurate survey estimates present several challenges. In 2015, the World Health Organization (WHO) released a working draft of its updated Vaccination Coverage Survey Reference Manual that moved well beyond the traditional Expanded Program on Immunization (EPI) survey design. In April 2017, WHO convened a four-day meeting, to review lessons learned using the updated manual and to define an agenda for operational research about vaccination coverage surveys. About 70 stakeholders, including EPI managers and participants from 10 countries that have used the updated Survey Manual, survey experts, statisticians, partners, representatives from WHO regional offices and headquarters, and providers of technical assistance discussed methodological issues from sampling to accurately ascertaining a person's vaccination status, optimizing data collection and data management and conducting appropriate analyses. Participants also discussed data sharing and how to best survey data for immunization decision-making. The lessons learned from the use of the updated WHO Survey Manual related mainly to operational issues to implement better quality vaccination coverage surveys. It resulted in a list of 23 recommendations for WHO, donors and partners, immunization programs, and household surveys that collect immunization data. Similarly, 14 research topics, categorized in six themes (overall survey conduction, sampling, vaccination ascertainment, data collection, data analysis and use, and inclusion of questions on knowledge, attitudes and practices) were prioritized. Top areas of further work included improving our understanding of the accuracy of caregiver recall when documented evidence of vaccination is not available, improving engagement and coordination between immunization programs and entities conducting multi-purpose household surveys such as Demographic and Health Survey and Multiple Cluster Indicator Survey, improving mechanisms for sharing vaccination survey datasets and documentation, and making better use of survey results to translate data into knowledge for decision-making. This manuscript summarizes the meeting proceedings and provides an update of actions taken by WHO since this meeting.

Global Routine Vaccination Coverage, 2015

In 1974, the World Health Organization (WHO) established the Expanded Program on Immunization* to provide protection against six vaccine-preventable diseases through routine infant immunization (1). Based on 2015 WHO and United Nations Children's Fund (UNICEF) estimates, global coverage with the third dose of diphtheria-tetanus-pertussis vaccine (DTP3), the first dose of measles-containing vaccine (MCV1) and the third dose of polio vaccine (Pol3) has remained stable (84%-86%) since 2010. From 2014 to 2015, estimated global coverage with the second MCV dose (MCV2) increased from 39% to 43% by the end of the second year of life and from 58% to 61% when older age groups were included. Global coverage was higher in 2015 than 2010 for newer or underused vaccines, including rotavirus vaccine, pneumococcal conjugate vaccine (PCV), rubella vaccine, Haemophilus influenzae type b (Hib) vaccine, and 3 doses of hepatitis B (HepB3) vaccine. Coverage estimates varied widely by WHO Region, country, and district; in addition, for the vaccines evaluated (MCV, DTP3, Pol3, HepB3, Hib3), wide disparities were found in coverage by country income classification. Improvements in equity of access are necessary to reach and sustain higher coverage and increase protection from vaccine-preventable diseases for all persons.

A global review of national influenza immunization policies: Analysis of the 2014 WHO/UNICEF Joint Reporting Form on immunization

Introduction

The WHO recommends annual influenza vaccination to prevent influenza illness in high-risk groups. Little is known about national influenza immunization policies globally.

Material and Methods

The 2014 WHO/UNICEF Joint Reporting Form (JRF) on Immunization was adapted to capture data on influenza immunization policies. We combined this dataset with additional JRF information on new vaccine introductions and strength of immunization programmes, as well as publicly available data on country economic status. Data from countries that did not complete the JRF were sought through additional sources. We described data on country influenza immunization policies and used bivariate analyses to identify factors associated with having such policies.

Results

Of 194 WHO Member States, 115 (59%) reported having a national influenza immunization policy in 2014. Among countries with a national policy, programmes target specific WHO-defined risk groups, including pregnant women (42%), young children (28%), adults with chronic illnesses (46%), the elderly (45%), and health care workers (47%). The Americas, Europe, and Western Pacific were the WHO regions that had the highest percentages of countries reporting that they had national influenza immunization policies. Compared to countries without policies, countries with policies were significantly more likely to have the following characteristics: to be high or upper middle income (p < 0.0001); to have introduced birth dose hepatitis B virus vaccine (p < 0.0001), pneumococcal conjugate vaccine (p = 0.032), or human papilloma virus vaccine (p = 0.002); to have achieved global goals for diphtheria-tetanus-pertussis vaccine coverage (p < 0.0001); and to have a functioning National Immunization Technical Advisory Group (p < 0.0001).

Conclusions

The 2014 revision of the JRF permitted a global assessment of national influenza immunization policies. The 59% of countries reporting that they had policies are wealthier, use more new or under-utilized vaccines, and have stronger immunization systems. Addressing disparities in public health resources and strengthening immunization systems may facilitate influenza vaccine introduction and use.

Monitoring vaccination coverage: Defining the role of surveys

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High quality community-based vaccination coverage surveys are resource-intensive.

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Other monitoring methods provide useful data for programme managers.

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Health facility-based assessments evaluate multiple aspects of service provision.

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Purposeful community samples give local health workers programmatic insights.

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To be useful, monitoring should lead to action to improve performance.

Vaccination coverage is a widely used indicator of programme performance, measured by registries, routine administrative reports or household surveys. Because the population denominator and the reported number of vaccinations used in administrative estimates are often inaccurate, survey data are often considered to be more reliable. Many countries obtain survey data on vaccination coverage every 3–5 years from large-scale multi-purpose survey programs. Additional surveys may be needed to evaluate coverage in Supplemental Immunization Activities such as measles or polio campaigns, or after major changes have occurred in the vaccination programme or its context.

When a coverage survey is undertaken, rigorous statistical principles and field protocols should be followed to avoid selection bias and information bias. This requires substantial time, expertise and resources hence the role of vaccination coverage surveys in programme monitoring needs to be carefully defined. At times, programmatic monitoring may be more appropriate and provides data to guide program improvement. Practical field methods such as health facility-based assessments can evaluate multiple aspects of service provision, costs, coverage (among clinic attendees) and data quality. Similarly, purposeful sampling or censuses of specific populations can help local health workers evaluate their own performance and understand community attitudes, without trying to claim that the results are representative of the entire population. Administrative reports enable programme managers to do real-time monitoring, investigate potential problems and take timely remedial action, thus improvement of administrative estimates is of high priority. Most importantly, investment in collecting data needs to be complemented by investment in acting on results to improve performance.

Influenza vaccination in the Americas: Progress and challenges after the 2009 A(H1N1) influenza pandemic

Background: There has been considerable uptake of seasonal influenza vaccines in the Americas compared to other regions. We describe the current influenza vaccination target groups, recent progress in vaccine uptake and in generating evidence on influenza seasonality and vaccine effectiveness for immunization programs. We also discuss persistent challenges, 5 years after the A(H1N1) 2009 influenza pandemic.

Methods: We compiled and summarized data annually reported by countries to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF joint report form on immunization, information obtained through PAHO's Revolving Fund for Vaccine Procurement and communications with managers of national Expanded Programs on Immunization (EPI).

Results: Since 2008, 25 countries/territories in the Americas have introduced new target groups for vaccination or expanded the age ranges of existing target groups. As of 2014, 40 (89%) out of 45 countries/territories have policies established for seasonal influenza vaccination. Currently, 29 (64%) countries/territories target pregnant women for vaccination, the highest priority group according to WHO´s Stategic Advisory Group of Experts and PAHO/WHO's Technical Advisory Group on Vaccine-preventable Diseases, compared to only 7 (16%) in 2008. Among 23 countries reporting coverage data, on average, 75% of adults ≥60 years, 45% of children aged 6–23 months, 32% of children aged 5–2 years, 59% of pregnant women, 78% of healthcare workers, and 90% of individuals with chronic conditions were vaccinated during the 2013–14 Northern Hemisphere or 2014 Southern Hemisphere influenza vaccination activities. Difficulties however persist in the estimation of vaccination coverage, especially for pregnant women and persons with chronic conditions. Since 2007, 6 tropical countries have changed their vaccine formulation from the Northern to the Southern Hemisphere formulation and the timing of their campaigns to April-May following the review of national evidence. LAC countries have also established an official network dedicated to evaluating influenza vaccines effectiveness and impact.

Conclusion: Following the A(H1N1)2009 influenza pandemic, countries of the Americas have continued their efforts to sustain or increase seasonal influenza vaccine uptake among high risk groups, especially among pregnant women. Countries also continued strengthening influenza surveillance, immunization platforms and information systems, indirectly improving preparedness for future pandemics. Influenza vaccination is particularly challenging compared to other vaccines included in EPI schedules, due to the need for annual, optimally timed vaccination, the wide spectrum of target groups, and the limitations of the available vaccines. Countries should continue to monitor influenza vaccination coverage, generate evidence for vaccination programs and implement social communication strategies addressing existing gaps.

Diphtheria in the Dominican Republic: reduction of cases following a large outbreak

OBJECTIVE

To describe the most recent outbreak of diphtheria in the Dominican Republic and the disease's occurrence and vaccination coverage in 2004-2013.

METHODS

Clinical data of diphtheria cases that occurred in 2004 and that met the study's case definition were reviewed along with socioeconomic and epidemiological information from the cases' families. Univariate and multivariate analyses were performed to assess risk factors for fatal diphtheria. Routine surveillance and vaccination coverage data are presented.

RESULTS

From January 2004-April 2005, a total of 145 diphtheria cases were reported; 80 (66%) of the 122 cases reported in 2004 met the case definition; 26 were fatal (case-fatality rate: 32.5%). Incidence was highest in the group 1-4 years of age at 5.3 per 100 000; 62.5% were male. Of the 80 cases, 61 (76%) where hospitalized in Hospital A, 17 in Hospital B, and 2 in two other hospitals. Earlier onset (first half of 2004), birth order, and tracheotomy were associated with fatal diphtheria (P < 0.05); cases in Hospital A were also more likely to be fatal (P = 0.066). The average annual diphtheria incidence was 4.91 cases/1 million people in 2000-2003, climbed to 8.8 cases per million in 2004-2005, and dropped to 0.38 in 2006-2014; no diphtheria cases have been reported since 2011. DTP3 vaccination coverage ranged from 72%-81% in 2000-2004 and from 81%-89% in 2005-2013.

CONCLUSIONS

The 2004-2005 diphtheria outbreak in the Dominican Republic resulted in important and avoidable morbidity and mortality. Annual cases declined and no cases have been reported in recent years. Maintaining high vaccination coverage and diligent surveillance are crucial to preventing diphtheria outbreaks and controlling the disease.