Routine Vaccination Coverage - Worldwide, 2020

Efficacy and immunogenicity of a single dose of human papillomavirus vaccine compared to multidose vaccination regimens or no vaccination: An updated systematic review of evidence from clinical trials

Objectives

This study systematically reviewed the published literature from clinical trials on the efficacy and immunogenicity of single-dose HPV vaccination compared to multidose schedules or no HPV vaccination.

Methods

Four databases were searched for relevant articles published from Jan-1999 to Feb-2023. Articles were assessed for eligibility for inclusion using pre-defined criteria. Relevant data were extracted from eligible articles and a descriptive quality assessment was performed for each study. A narrative data synthesis was conducted, examining HPV infection, other clinical outcomes and immunogenicity responses by dose schedule.

Results

Fifteen articles reporting data from six studies (all in healthy young females) were included. One article was included from each of three studies that prospectively randomised participants to receive a single HPV vaccine dose versus one or more comparator schedule(s). The other 12 articles reported data from three studies that randomised participants to receive multidose HPV vaccine (or control vaccine) schedules; in those studies, some participants failed to complete their allocated schedule, and evaluations were conducted to compare participants who actually received one, two or three doses. Across all efficacy studies, the incidence or prevalence of HPV16/18 infection was very low among HPV-vaccinated participants, regardless of the number of doses received; with no evidence for a difference between dose groups. In immunogenicity studies, HPV16/18 antibody seropositivity rates were high among all HPV-vaccinated participants. Antibody levels were significantly lower with one dose compared to two or three doses, but levels with one dose were stable and sustained to 11 years post-vaccination.

Conclusions

Results from this review support recent World Health Organization recommendations allowing either one- or two-dose HPV vaccination in healthy young females. Longer-term efficacy and immunogenicity data from ongoing studies are awaited. Randomised trials of single-dose HPV-vaccination are urgently needed in other populations, e.g. boys, older females and people with HIV.

Whole-genome analysis of human group A rotaviruses in 1980s Japan and evolutionary assessment of global Wa-like strains across half a century

Historically, the Wa-like strains of human group A rotavirus (RVA) have been major causes of gastroenteritis. However, since the 2010s, the circulation of non-Wa-like strains has been increasingly reported, indicating a shift in the molecular epidemiology of RVA. Although understanding RVA evolution requires the analysis of both current and historical strains, comprehensive pre-1980's sequencing data are scarce globally. We determined the whole-genome sequences of representative strains from six RVA gastroenteritis outbreaks observed at an infant home in Sapporo, Japan, between 1981 and 1989. These outbreaks were mainly caused by G1 or G3 Wa-like strains, resembling strains from the United States in the 1970s-1980s and from Malawi in the 1990s. Phylogenetic analysis of these infant home strains, together with Wa-like strains collected worldwide from the 1970s to 2020, revealed a notable trend: pre-2010 strains diverged into multiple lineages in many genomic segments, whereas post-2010 strains tended to converge into a single lineage. However, Bayesian skyline plot indicated near-constant effective population sizes from the 1970s to 2020, and selection pressure analysis identified positive selection only at amino acid 75 of NSP2. These results suggest that evidence supporting the influence of rotavirus vaccines, introduced globally since 2006, on Wa-like RVA molecular evolution is lacking at present, and phylogenetic analysis may simply reflect natural fluctuations in RVA molecular evolution. Evaluating the long-term impact of RV vaccines on the molecular evolution of RVA requires sustained surveillance.

Global elimination of HBV: Is it really achievable?

Hepatitis B virus (HBV) infection is a major cause of premature death worldwide. In 2016, the World Health Organization (WHO) called for HBV elimination and set up very ambitious elimination targets. The development of effective vaccines, accurate diagnostic tools and safe antiviral drugs make HBV elimination a realistic goal. However, the most constrained-resource regions, which bear the highest burden of HBV, are facing major challenges in implementing strategies to reduce HBV incidence and mortality. Developing simplified approaches adapted to resource-limited settings and scaling up interventions for the prevention and control of HBV globally are urgently needed. Whether HBV elimination will be achieved in an equitable manner and in a reasonable timeframe remains highly uncertain.

Epidemiology of HPV-associated cancers past, present and future: towards prevention and elimination

Cervical cancer is the first cancer deemed amenable to elimination through prevention, and thus lessons from the epidemiology and prevention of this cancer type can provide information on strategies to manage other cancers. Infection with the human papillomavirus (HPV) causes virtually all cervical cancers, and an important proportion of oropharyngeal, anal and genital cancers. Whereas 20th century prevention efforts were dominated by cytology-based screening, the present and future of HPV-associated cancer prevention relies mostly on HPV vaccination and molecular screening tests. In this Review, we provide an overview of the epidemiology of HPV-associated cancers, their disease burden, how past and contemporary preventive interventions have shaped their incidence and mortality, and the potential for elimination. We particularly focus on the cofactors that could have the greatest effect on prevention efforts, such as parity and human immunodeficiency virus infection, as well as on social determinants of health. Given that the incidence of and mortality from HPV-associated cancers remain strongly associated with the socioeconomic status of individuals and the human development index of countries, elimination efforts are unlikely to succeed unless prevention efforts focus on health equity, with a commitment to both primary and secondary prevention.

Factors Associated with Vaccination Coverage among 0-59-Month-Old Children: A Multilevel Analysis of the 2020 Somaliland Demographic and Health Survey

Globally, there has been little growth in vaccination coverage, with countries in the Horn of Africa having the lowest vaccination rates. This study investigated factors associated with vaccination status among children under five years old in Somaliland. The 2020 Somaliland Demographic and Health Survey surveyed women aged 15-49 years from randomly selected households. This multilevel analysis included 2673 primary caregivers of children under five. Only 34% of children were ever vaccinated. Childhood vaccination coverage was positively associated with high-budget regions, high healthcare facility density, and children older than 23 months. Vaccination coverage was greater for urban and rural residents than for nomadic people. Children whose mothers could read part of one sentence or one complete sentence were more likely to be vaccinated than illiterate mothers. Children whose mothers received antenatal care (ANC) once, two to three times, or four times or more were more likely to be vaccinated than those whose mothers received no ANC. Childhood vaccination coverage in Somaliland is low. Promoting maternal ANC visits and increasing women's literacy may enhance vaccination coverage. Funds should be allocated to areas with low resources, particularly for nomadic people, to boost vaccination uptake.

Measles Vaccine Coverage and Disease Outbreaks: A Systematic Review of the Early Impact of COVID-19 in Low and Lower-Middle Income Countries

Objectives: We aimed to evaluate changes to measles-containing vaccine (MCV) provision and subsequent measles disease cases in low- and lower-middle income countries (LICs, LMICs) in relation to the COVID-19 pandemic. Methods: A systematic search was conducted of MEDLINE, OVID EMBASE and PubMed records. Primary quantitative and qualitative research studies published from January 2020 were included if they reported on COVID-19 impact on MCV provision and/or measles outbreak rates within LICs and LMICs. Results: 45 studies were included. The change in MCV1 vaccination coverage in national and international regions ranged -13% to +44.4% from pre-COVID time periods. In local regions, the median MCV1 and overall EPI rate changed by -23.3% and -28.5% respectively. Median MCV2 rate was disproportionally impacted in local areas during COVID-interruption time-periods (-48.2%) with ongoing disruption in early-recovery time-periods (-17.7%). 8.9% of studies reported on vaccination status of confirmed measles cases; from these, 71%-91% had received no MCV dose. Conclusion: MCV vaccination coverage experienced ongoing disruption during the recovery periods after initial COVID-19 disruption. Vaccination in local area datasets notably experienced longer-term disruption compared to nationally reported figures.

Evidence for Immunity against Tetanus, Diphtheria, and Pertussis through Natural Infection or Vaccination in Adult Solid Organ Transplant Recipients: A Systematic Review

(1) Background: We aim to systematically review the current evidence on immunity against tetanus, diphtheria, and pertussis in adult solid organ transplantation (SOT) recipients, either through natural infection or vaccination. (2) Methods: This systematic review was conducted per PRISMA guidelines. We assessed the risk of bias using the Cochrane RoB 2 and ROBINS-I and summarized the findings narratively due to the heterogeneity of the studies. (3) Results: Of the 315 screened articles, 11 were included. Tetanus immunity varied between 55% and 86%, diphtheria immunity from 23% to 75%, and pertussis immunity was between 46% and 82%. Post-vaccination immunity showed variation across the studies, with some indicating reductions and others no change, with antibody responses influenced by transplanted organs, gender, age, and immunosuppressive regimens. The single randomized study exhibited a low risk of bias, while of the ten non-randomized studies, six showed moderate and four serious risks of bias, necessitating cautious interpretation of results. (4) Conclusions: SOT recipients exhibit considerable immunity against tetanus and diphtheria at transplantation, but this immunity decreases over time. Although vaccination can enhance this immunity, the response may be suboptimal, and the increased antibody levels may not persist, underscoring the need for tailored vaccination strategies in this vulnerable population.

The Association between Parental Child Vaccination Refusal Rate and the Impact of Mass Vaccination against COVID-19 in Kazakhstan: An Interrupted Time Series Analysis with Predictive Modelling of Nationwide Data Sources from 2013 to 2022

Despite well-established evidence supporting vaccination efficacy in reducing morbidity and mortality among infants and children, there is a global challenge with an increasing number of childhood vaccination refusals. This issue has intensified, especially during the COVID-19 pandemic. Our study aims to forecast mandatory childhood vaccination refusal trends in Kazakhstan until 2030, assessing the impact of mass COVID-19 vaccination on these rates. Utilizing annual official statistical data from 2013 to 2022 provided by the Ministry of Health of Kazakhstan, the study reveals a significant surge in refusals during the pandemic and post-pandemic periods, reaching record levels of 42,282 cases in 2021 and 44,180 cases in 2022. Notably, refusal rates sharply rose in specific regions, like Aktobe (13.9 times increase) and Atyrau (4.29 times increase), emphasizing the need for increased public healthcare attention in these areas. However, despite a decade of data, our forecasting analysis indicates a lack of volatility in childhood vaccine refusal trends for all vaccine types up to 2030, highlighting the statistical significance of the obtained results. The increasing trend in vaccine refusals underscores the necessity to enhance crisis response and support health initiatives, particularly in regions where a substantial rise in refusals has been observed in recent years.

Strategies for expanding childhood vaccination in the Americas following the COVID-19 pandemic

Objective

To provide an overview of the status of the childhood vaccination schedule in the Americas, outline program structures, and identify updated implementation strategies to improve vaccination coverage following the COVID-19 pandemic.

Methods

A group of experts in pediatrics, epidemiology, vaccines, and global and public health discussed the current status of the childhood vaccination schedule in the Americas, describing the program structure and identifying new implementation strategies that have the potential to improve vaccination coverage in the post-pandemic context, after the challenges COVID-19 presented for more than two years.

Results

The Americas currently face a high risk of resurgence of diseases that were previously controlled or eliminated. Therefore, it is important to find new strategies to educate citizens on the risks associated with lower vaccination rates, especially in children.

Conclusions

New strategies along with strong mobilization of the population and advocacy by citizens are necessary to prevent antivaccination groups from gaining a stronger presence in the region and jeopardizing the credibility of the Expanded Program on Immunization.

Estimating the health effects of COVID-19-related immunisation disruptions in 112 countries during 2020-30: a modelling study

BACKGROUND

There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered.

METHODS

For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up.

FINDINGS

We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]).

INTERPRETATION

Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption.

FUNDING

The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation.

TRANSLATIONS

For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.

Exploring blood lipids-immunity associations following HBV vaccination: evidence from a large cross-sectional study

Introduction

Serological responses following hepatitis B vaccination are crucial for preventing hepatitis B (HBV). However, the potential relationship between serum lipid levels and immunity from HBV vaccination remains poorly understood.

Methods

In this study, we conducted an analysis of the National Health and Nutrition Examination Survey (NHANES) data spanning from 2003 to 2016. Multivariable weighted logistic regression models, generalized linear analysis, stratified models, smooth curve fitting, segmentation effect analysis and sensitivity analysis were utilized to assess the relationships.

Results

After adjusting for relevant covariates, we observed that low levels of high-density lipoprotein cholesterol (HDL) were independently linked to a significantly lower seroprotective rate. Compared to HDL levels of ≥ 60 mg/dL, the odds ratios (ORs) for individuals with borderline levels (40-59 mg/dL for men, 50-59 mg/dL for women) and low levels (< 40 mg/dL for men, < 50 mg/dL for women) were 0.83 (95% CI 0.69-0.99) and 0.65 (95% CI 0.56-0.78), respectively. This association was particularly pronounced in individuals aged 40 or older. Conversely, higher levels of the triglyceride to HDL (TG/HDL) ratio (OR, 0.90; 95% CI, 0.84-0.98), total cholesterol to HDL (Chol/HDL) ratio (OR, 0.77; 95% CI, 0.64-0.92), and low-density lipoprotein to HDL (LDL/HDL) ratio (OR, 0.85; 95% CI, 0.76-0.96) were associated with a decreased likelihood of seroprotection.

Conclusion

This study suggests that lipid levels may play a role in modulating the immune response following HBV vaccination.

Using the AS04C-adjuvanted hepatitis B vaccine in patients classified as non-responders

BACKGROUND

Chronic hepatitis B (HB) remains a significant global health concern, despite the widespread availability of the HB vaccine. While the standard vaccine demonstrates an impressive serological response rate exceeding 90%, a subset of individuals exhibit suboptimal immunity. This study aims to elucidate the efficacy of the AS04C-adjuvanted HB vaccine in addressing non-responsiveness.

METHODS

Conducted at the Preventive Medicine Service of the University Albacete Hospital in Spain from 2017 to 2021, this single-center observational study enrolled 195 patients. Among them, 126 (65%) were classified as non-responders following one or two complete standard vaccination courses.

RESULTS

After the administration of a complete four-dose regimen of the AS04C-adjuvanted vaccine, 73.81% of non-responder patients exhibited antibody titers indicative of robust immunity (anti-HBs >10).

CONCLUSIONS

These findings underscore the pivotal role of the AS04C-adjuvanted HB vaccine in addressing non-responsiveness, emphasizing its potential as a crucial tool in augmenting immunization strategies for various populations. This includes non-responders to standard vaccination, individuals with chronic kidney disease, those requiring seroprotection due to factors like immunosuppression or occupational hazards, as well as patients for whom conventional revaccination strategies have proven futile. Additional research is needed to expand on the promising results obtained through our protocol.

Impact of the COVID-19 pandemic on routine vaccination coverage under varying prevalence Conditions: A cohort study in Beijing, China

BACKGROUND

The COVID-19 pandemic has experienced various phases including outbreaks, a global health crisis, and eventual de-escalation from a public health emergency of international concern, significantly affecting the delivery and utilization of healthcare services. This study aimed to evaluate the impact of the COVID-19 pandemic on the coverage rate of routine immunization in children under varying prevalence conditions.

METHODS

We conducted a retrospective, population-based cohort study in Beijing, China, utilizing stratified random sampling by birthdate to obtain a sample of 29,811 participants. Subjects were categorized into four cohorts based on when they became eligible for vaccination: the Pre-COVID Period cohort, the COVID-19 Low Epidemic Period cohort, the COVID-19 Surging Period cohort, and the COVID-19 Slowing Down Period cohort. A one-month follow-up was conducted. Cox proportional hazards model was employed to examine associations between the COVID-19 epidemic status and timely vaccination.

RESULTS

Participants age-eligible for vaccination during the COVID-19 Low Epidemic Period demonstrated higher rates of timely vaccination (HR 1.18, 95% CI 1.15-1.22) compared to those eligible during the Pre-COVID Period. Conversely, those eligible during the COVID-19 Surging Period displayed lower rates (HR 0.73, 95% CI 0.66-0.82). No significant difference in vaccination timeliness was observed for those eligible during the COVID-19 Slowing Down Period in comparison to the Pre-COVID Period (HR 0.99, 95% CI 0.91-1.09). By the end of May 2023, DTP3 rate among eligible children during the COVID-19 Surging Period had surpassed 90%.

CONCLUSIONS

Significantly declining rates of timely vaccination were observed during the COVID-19 Surging Period, which lasted two months, but not during the nearly three-year-long COVID-19 Low Epidemic Period. An upward trend in vaccination timeliness followed, culminating in a return to baseline levels over the subsequent 3-4 months. Our findings suggested that the pandemic exerted a decreasing and recoverable impact on the coverage rate of routine immunizations in China.

Emerging pneumococcal serotypes in Iraq: scope for improved vaccine development

Pneumococcal disease is a global public health concern as it affects the young, aged and the immunocompromised. The development of pneumococcal vaccines and their incorporation in the immunization programs has helped to reduce the global burden of disease. However, serotype replacement and the emergence of non-vaccine serotypes as well as the persistence of a few vaccine serotypes underscores the need for development of new and effective vaccines against such pneumococcal serotypes. In the Middle East, places of religious mass gatherings are a hotspot for disease transmission in addition to the global risk factors. Therefore, the periodic surveillance of pneumococcal serotypes circulating in the region to determine the effectiveness of existing prevention strategies and develop improved vaccines is warranted. Currently, there is a lack of serotype prevalence data for Iraq due to inadequate surveillance in the region. Thus, this review aims to determine the pneumococcal serotypes circulating in Iraq which may help in the development and introduction of improved pneumococcal vaccines in the country.

Access to DTP-Based Combination Vaccines in Asia-Pacific Countries between 2019 and 2022

The Asia-Pacific countries are highly diverse in health and economic conditions that may impact vaccine access and uptake. Our study aimed to characterize patterns of health access to DTP-based combination vaccines in 10 countries from 2019 to 2022 using the IQVIA-MIDAS database. The availability, affordability, and accessibility were compared across countries by national health and economic performance indicators using Spearman's rank correlation coefficient. Our findings showed that the three aspects of access to DTP-based vaccines varied substantially in the Asia-Pacific region, with higher levels in countries with better health and economic performance. Affected by the COVID-19 pandemic, vaccine accessibility fluctuates significantly in lower-income countries, with DTP coverage rates falling by more than 14% in the Philippines and Indonesia between 2019 and 2021. For availability and affordability, Singapore and Malaysia from high-income groups were largely affected, which may be related to health expenditure as a percentage of gross domestic product (Coefficient = 0.39, p = 0.03). Our study indicates that greater attention needs to be paid to national health expenditure and routine immunization services to improve vaccine disparities and increase the robustness and resilience of the vaccine supply chain during public health emergencies.

Routine pediatric vaccinations during the COVID-19 pandemic: A review of the global impact

The coronavirus disease 2019 (COVID-19) pandemic has put standard, routine childhood vaccinations at risk worldwide. The disruption in vaccine coverage has resulted in a negative impact on the health of children, with some races, ethnicities, age groups, areas of settlement, and parts of the world affected more than others. This literature review studied and examined the impact of COVID-19 on infant, child, and adolescent vaccinations. Retrospectively, the analysis showed a decline, delays, or interruptions in the coverage of vaccines during the pan-demic and a decline in some countries' pre-pandemic and post-pandemic eras. Necessary attempts and efforts should be made for these delayed and missed vaccinations, as failure to do so could put children's health at risk. Thus, priority should be directed at instituting catch-up programs to support vaccine uptake and decrease the probability of acquiring vaccine-preventable diseases.

Analysis of global routine immunisation coverage shows disruption and stagnation during the first two-years of the COVID-19 pandemic with tentative recovery in 2022

Whilst it is now widely recognised that routine immunisation (RI) was disrupted by the COVID-19 pandemic in 2020, and further so in 2021, the extent of continued interruptions in 2022 and/or rebounds to previous trends remains unclear. We modelled country-specific RI trends using validated estimates of national coverage from the World Health Organisation and United Nation Children's Fund for 182 countries (accounting for > 97% of children globally), to project expected diphtheria, tetanus, and pertussis-containing vaccine first-dose (DTP1), third-dose (DTP3) and measles-containing vaccine first-dose (MCV1) coverage for 2020-2022 based on pre-pandemic trends (from 2000 to 2019). We provide further evidence of peak pandemic immunisation disruption in 2021, followed by tentative recovery in 2022. We report a 3.4% (95 %CI: [2.5%; 4.4%]) decline in global DTP3 coverage in 2021 compared to 2000-2019 trends, from an expected 89.8% to reported 86.4%. This coverage gap reduced to a 2.7% (95 %CI: [1.8%; 3.6%]) decline in 2022, with reported coverage rising to 87.2%. Similar results were seen for DTP1 and MCV1. Whilst partial rebounds are encouraging, global coverage decline translates to a 17-year setback in RI to 2005 levels, and the majority of countries retain coverage at or lower than pre-pandemic levels. The Americas, Africa, and Asia were the most impacted regions; and low- and middle-income countries the most affected income groups. The number of annual Zero Dose (ZD) children - indicating those receiving no immunisations - increased from 12.1 million (M) globally in 2019 to a peak of 16.7 M in 2021, then reduced to 13.1 M in 2022. Overall, we estimate an excess of 8.8 M ZD children cumulatively in 2020-2022 compared to pre-pandemic levels. This work can be used as an objective baseline to inform future interventions to prioritise and target interventions, and facilitate catch-up of growing populations of under- and un-immunised children.

Health system barriers to timely routine measles vaccinations in rural southwest China: a qualitative study on the perspectives of township vaccination professionals and village doctors

OBJECTIVES

A well-functioning health system ensures timely routine measles vaccinations for age-appropriate children, minimising measles risk. However, there is limited knowledge about the impact of the performance of immunisation programmes in health systems on the timeliness of measles vaccination. This study aimed to identify health system barriers to timely routine measles vaccination in rural southwest China, integrating the perspectives of township vaccination professionals and village doctors.

DESIGN, SETTING AND PARTICIPANTS

Qualitative study among township vaccination professionals and village doctors in rural Guangxi, southwest China.

METHODS

20 focus group discussions (FGDs) at township level and 120 in-depth interviews (IDIs) at village level, based on a four-theme framework. We used convenience sampling to recruit 60 township vaccination professionals and 120 village doctors in 2015. Instruments used were a semistructured questionnaire and interview outlines. We collected township and village-level data focusing on themes of health resources allocation, pattern of vaccination services, management and supervision of vaccination services, and perceptions of vaccination policy. The FGDs and IDIs were audio-recorded and transcribed. Braun and Clarke's thematic analysis approach was adopted to synthesise findings into meaningful subthemes, narrative text and illustrative quotations.

RESULTS

The health system barriers to timely routine vaccinations were explored across four themes. Barriers in the health resources allocation theme comprised (1) inadequacy of vaccination-related human resources (eg, lack of township vaccination professionals and lack of young village doctors), and (2) incompatible and non-identical information system of vaccination services across regions. Barriers in the pattern of vaccination services theme included inflexible vaccination services models, for example, routine vaccination services being offered monthly on fixed vaccination days, limited numbers of vaccination days per month, vaccination days being set on non-local market days, vaccination days being clustered into a specific period and absence of formal vaccination appointments. Ineffective economic incentive mechanism was identified as a barrier in the management and supervision of vaccination services theme. Low-degree participation of village doctors in routine vaccination services was identified as a barrier in the perceptions of vaccination policy theme.

CONCLUSIONS

We encourage policymakers and stakeholders to apply these findings to improve the timeliness of routine vaccination. Barriers to timely routine vaccination include inadequate allocation of vaccination-related resources and inflexible vaccination service delivery models. Financial and non-financial incentives should be used to retain and recruit vaccination professionals and village doctors. Strengthening information systems with unified data standards enables cross-regional data exchange. Optimising immunisation services and rationalising vaccination days could eliminate health system barriers and improve vaccination timeliness in rural China.

Temporal trend of the dropout rate and vaccination coverage of the triple viral vaccine in Brazil, 2014-2021

MAIN RESULTS

Annual vaccination coverage was below 95% in Brazil. The second dose of the vaccine showed stationary and decreasing trends in the country's Federative Units. The dropout rate varied greatly throughout the study period.

IMPLICATIONS FOR SERVICES

The results found regarding the trends serve to inform and point to the urgency of planning actions aimed at improving coverage of the triple viral vaccine nationally in Brazil.

PERSPECTIVES

Investments in enhanced training of epidemiological surveillance professionals and enhanced computerized systems are necessary, with a view to continuous monitoring, to support actions to promote better and timely vaccine coverage.

OBJECTIVE

to analyze the temporal trend of coverage and dropout rate for triple viral vaccine in Brazil, according to the country's Federative Units and Macro-Regions, between 2014 and 2021.

METHODS

this was an ecological time series study, using data from the National Immunization Program Information System and the Live Birth Information System; joinpoint regression models were used.

RESULTS

in Brazil as a whole annual vaccination coverage was below 95% and ranged from 92.3% (2015) to 54.4% (2021); the second dose of the vaccine showed a decreasing temporal trend in the period (average change over the period = -5.8; 95%CI -10.5;-0.8); the temporal trends were stationary and decreasing in the country's Federative Units; the dropout rate ranged from 22.2% (2014) to 37.4% (2021).

CONCLUSION

there was a downward trend in vaccination coverage and an increase in the dropout rate in Brazil as a whole and in the country's Federative Units.

Parental attitudes, beliefs and behaviors toward childhood and COVID-19 vaccines: A countrywide survey conducted in Kazakhstan examining vaccine refusal and hesitancy

BACKGROUND

Vaccination rates worldwide have declined in recent years. This decrease is primarily driven by vaccine hesitancy, which remains understudied in Central Asia, including Kazakhstan. Furthermore, there is great concern about parental hesitancy toward COVID-19 vaccines, as previous studies have focused on adult vaccine hesitancy. The current study was conducted by UNICEF and funded by USAID to explore the drivers of routine and COVID-19 immunization behaviors among parents and caregivers in Kazakhstan.

METHODS

Using a cross-sectional methodology, researchers conducted 3081 face-to-face interviews with parents and caregivers of children aged 0-17 years across cities and villages in Kazakhstan. A tablet-based questionnaire (CAPI) was utilized, collecting participants' data on sociodemographic characteristics, childhood and COVID-19 vaccination behaviors, and potential drivers.

RESULTS

Total of 239 participants (7.8%) were found to previously refuse vaccination due to their own beliefs. Stronger belief that vaccines are efficacious (AdjOR = 0.47), stronger belief that childhood vaccines are safe and danger of vaccine-preventable diseases is high (AdjOR = 0.73), firmer trust in societal factors (AdjOR = 0.77) and positive attitudes of family members toward immunization (AdjOR = 0.6) were significantly associated with parental refusal of childhood vaccines. The large proportion of respondents (N = 2,634, 85.6%) missed the COVID-19 vaccination of their child or were unwilling to get vaccinated. Stronger belief that COVID-19 vaccines are safe and efficacious (AdjsOR = 0.18), lacking important information about COVID-19 vaccines (AdjOR = 1.25) and parents being unvaccinated against COVID-19 (AdjOR = 2.3) were significant predictors of vaccine hesitancy.

CONCLUSION

This study revealed numerous socio-demographic and behavioral factors significantly associated with parental refusal of childhood vaccines and hesitancy toward COVID-19 vaccines. Many parents not refusing vaccination possessed negative attitudes towards vaccines. Potential changes in their attitudes and beliefs of parents were observed compared to findings from pre-COVID era. Continuous monitoring of parental hesitancy, proper interventions and education of healthcare workers are suggested to reduce parental vaccine hesitancy.

The Impact of Social Media on Vaccination: A Narrative Review

Vaccine hesitancy poses a significant global health challenge, fueled by misinformation and anti-vaccination campaigns on social media platforms (SMPs). This study examines the influence of social media on coronavirus disease 2019 (COVID-19) and non-COVID-19 vaccination in Asia during the peri-pandemic period. Through a comprehensive analysis of available literature, we aim to elucidate the role of SMPs in shaping vaccination attitudes and behaviors. The findings highlight the detrimental impact of social media on vaccination efforts and provide insights into addressing vaccine hesitancy during this critical period. A narrative review was conducted by searching the PubMed, Scopus, and Google Scholar databases from inception to May 26, 2022. Only English-language articles involving human participants from Asian countries were included in this review. Out of the 228 articles identified through the database search, 14 articles were included in the final analysis. The prevalence of COVID-19 vaccine hesitancy or negative attitudes towards COVID-19 vaccines in Asian countries was found to be high, ranging from 20% to 55% across countries. Notably, reliance on SMPs for vaccine-related information was associated with a higher likelihood of COVID-19 vaccine hesitancy. This trend coincided with the proliferation of misinformation and conspiracy theories that portrayed COVID-19 vaccines as harmful during the pandemic. Similar patterns were observed for other types of vaccines, including polio, measles mumps and rubella, and diphtheria-tetanus-pertussis vaccines. The use of SMPs was also found to be associated with increased fear among caregivers in Asian countries, as well as a 3-4 times higher likelihood of delayed immunization. SMPs negatively impact vaccine intent in Asia due to misinformation and anti-vaccination campaigns during the pandemic. However, they can be a powerful tool for healthcare providers and policymakers to promote informed decision-making. Efforts should focus on leveraging SMPs to disseminate reliable information and combat hesitancy, fostering a well-informed and vaccinated population in Asia.

Interventions to Vaccinate Zero-Dose Children: A Narrative Review and Synthesis

Zero-dose children, or children who have not received any routine vaccination, are a priority population for global health policy makers as these children are at high risk of mortality from vaccine-preventable illnesses. We conducted a narrative review to identify potential interventions, both within and outside of the health sector, to reach zero-dose children. We reviewed the peer-reviewed and grey literature and identified 27 relevant resources. Additionally, we interviewed six key informants to enhance the synthesis of our findings. Data were organized into three priority settings: (1) urban slums, (2) remote or rural communities, and (3) conflict settings. We found that zero-dose children in the three priority settings face differing barriers to vaccination and, therefore, require context-specific interventions, such as leveraging slum health committees for urban slums or integrating with existing humanitarian response services for conflict settings. Three predominant themes emerged for grouping the various interventions: (1) community engagement, (2) health systems' strengthening and integration, and (3) technological innovations. The barriers to reaching zero-dose children are multifaceted and nuanced to each setting, therefore, no one intervention is enough. Technological interventions especially must be coupled with community engagement and health systems' strengthening efforts. Evaluations of the suggested interventions are needed to guide scale-up, as the evidence base around these interventions is relatively small.

Does Early Childhood BCG Vaccination Improve Survival to Midlife in a Population With a Low Tuberculosis Prevalence? Quasi-experimental Evidence on Nonspecific Effects From 32 Swedish Birth Cohorts

The Bacillus Calmette-Guérin (BCG) vaccine for tuberculosis (TB) is widely used globally. Many high-income countries discontinued nationwide vaccination policies starting in the 1980s as the TB prevalence decreased. However, there is continued scientific interest in whether the general childhood immunity boost conferred by the BCG vaccination impacts adult health and mortality in low-TB contexts (known as nonspecific effects). While recent studies have found evidence of an association between BCG vaccination and survival to ages 34-45, it is unclear whether these associations are causal or driven by the unobserved characteristics of those who chose to voluntarily vaccinate. We use the abrupt discontinuation of mandatory BCG vaccination in Sweden in 1975 as a natural experiment to estimate the causal nonspecific effect of the BCG vaccine on cohort survival to midlife. Applying two complementary study designs, we find no evidence that survival to age 40 was affected by the discontinuation of childhood BCG vaccination. The results are consistent among both males and females and are robust to several sensitivity tests. Overall, despite prior correlational studies suggesting large nonspecific effects, we do not find any population-level evidence for a nonspecific effect of the BCG vaccine discontinuation on survival to age 40 in Sweden.

Predictors for Uptake of Vaccines Offered during the Second Year of Life: Second Dose of Measles-Containing Vaccine and Meningococcal Serogroup A-Containing Vaccine, Ghana, 2020

BACKGROUND

Understanding the drivers of coverage for vaccines offered in the second year of life (2YL) is a critical focus area for Ghana's life course approach to vaccination. This study characterizes the predictors of vaccine receipt for 2YL vaccines-meningococcal serogroup A conjugate vaccine (MACV) and the second dose of measles-containing vaccine (MCV2)-in Ghana.

METHODS

1522 children aged 18-35 months were randomly sampled through household surveys in the Greater Accra Region (GAR), Northern Region (NR), and Volta Region (VR). The association between predictors and vaccination status was modeled using logistic regression with backwards elimination procedures. Predictors included child, caregiver, and household characteristics.

RESULTS

Coverage was high for infant vaccines (>85%) but lower for 2YL vaccines (ranging from 60.2% for MACV in GAR to 82.8% for MCV2 in VR). Predictors of vaccination status varied by region. Generally, older, first-born children, those living in rural settlements and those who received their recommended infant vaccines by their first birthday were the most likely to have received 2YL vaccines. Uptake was higher among those with older mothers and children whose caregivers were aware of the vaccination schedule.

CONCLUSIONS

Improving infant immunization uptake through increased community awareness and targeted strategies, such as parental reminders about vaccination visits, may improve 2YL vaccination coverage.

Strategies and Trends in COVID-19 Vaccination Delivery: What We Learn and What We May Use for the Future

Vaccination has been the most effective way to control the outbreak of the COVID-19 pandemic. The numbers and types of vaccines have reached considerable proportions, even if the question of vaccine procedures and frequency still needs to be resolved. We have come to learn the necessity of defining vaccination distribution strategies with regard to COVID-19 that could be used for any future pandemics of similar gravity. In fact, vaccine monitoring implies the existence of a strategy that should be measurable in terms of input and output, based on a mathematical model, including death rates, the spread of infections, symptoms, hospitalization, and so on. This paper addresses the issue of vaccine diffusion and strategies for monitoring the pandemic. It provides a description of the importance and take up of vaccines and the links between procedures and the containment of COVID-19 variants, as well as the long-term effects. Finally, the paper focuses on the global scenario in a world undergoing profound social and political change, with particular attention on current and future health provision. This contribution would represent an example of vaccination experiences, which can be useful in other pandemic or epidemiological contexts.

Clinical and Epidemiologic Profile of Invasive Pneumococcal Disease in Australian Children Following the Relaxation of Nonpharmaceutical Interventions Against SARS-COV-2

A global resurgence of invasive pneumococcal disease (IPD) has been noted in children. We provide a detailed clinical and epidemiological analysis of IPD in Australian children following relaxation of nonpharmaceutical interventions against coronavirus disease 2019, revealing significant morbidity and mortality-even in vaccinated children without known predisposing risk factors. Almost half of the IPD cases were caused by serotypes not covered by the 13-valent pneumococcal conjugate vaccine.

Estimating Vaccine Hesitancy in Colorado by Using Immunization Information System Data

OBJECTIVES

Vaccine hesitancy is a complex issue that threatens global health. We used data from the Colorado Immunization Information System (CIIS) to quantify vaccine hesitancy.

METHODS

We examined immunization records from CIIS for patients age 2 up to 9 months to estimate vaccine hesitancy by tabulating the number of doses received per visit and comparing it with the number of expected doses based on recommendations of the Advisory Committee on Immunization Practices. We calculated the percentage of patients in each vaccine hesitancy group who were up to date on the 7-antigen series by age 35 months. We examined the distribution of vaccine-hesitant populations among vaccination providers who report to CIIS to estimate the difference in vaccine-hesitant patient populations among vaccination providers in Colorado.

RESULTS

Of 201 450 patients, 5147 (2.6%) consistently limited the number of shots received at each visit as compared with recommendations from the Advisory Committee on Immunization Practices; 166 927 (82.9%) patients did not limit the number of shots received; 5693 (2.8%) limited the number of shots received at >1 visit but not all visits; and 23 683 (11.8%) limited the number of shots received at only 1 visit. We found differences in vaccine hesitancy distributions among certain Colorado vaccination providers.

CONCLUSIONS

Immunization information system data, although sometimes incomplete, offer an opportunity to investigate state-level vaccine hesitancy. Areas of future research include performing similar analyses over time and determining geographic and socioeconomic factors that contribute to vaccine hesitancy.

Evaluating Country Performance After Transitioning From Gavi Assistance: An Applied Synthetic Control Analysis

INTRODUCTION

Over the past decade, international development assistance for health has slowed. As donors seek to increase domestic cofinancing and ultimately transition countries from donor aid dependence, COVID-19 has severely constrained public budgets. The evaluation of sustainability and longer-term impacts of donor withdrawal is increasingly important. We assess vaccination coverage and post-neonatal mortality to estimate country performance of these outcomes among countries that no longer received assistance from Gavi, the Vaccine Alliance (Gavi) between 2000 and 2018.

METHODS

Using data from all countries receiving Gavi support between 2000 and 2020, we employed a synthetic control method to generate a pre-transition counterfactual with the same characteristics as the observation of interest to predict a future that empirically never existed. The synthetic unit is constructed from the weighted average of other units with good fit to the unit of interest before transition but did not transition.

RESULTS

We found substantial heterogeneity after transitioning from Gavi assistance. China, Guyana, and Turkmenistan overperformed their expected coverage rates; Albania, Bhutan, China, Guyana, and Turkmenistan maintained coverage over 90%; and Bosnia and Herzegovina and Ukraine reported precipitous drop-offs that fell well below their synthetic controls. We also observed a vaccination coverage decline in 2020 for several countries after transitioning and most synthetic controls, which we attribute to COVID-19-related service disruptions.

CONCLUSIONS

We recommend that Gavi adjust its transition model to systematically assess contextual externalities and risk. In addition, countries that no longer receive Gavi assistance can leverage technical assistance and communities of practice to mutually assist each other and other countries advancing toward transition. This could also foster intracountry accountability after transition. We also recommend that Gavi systematize post-transition assessments and evaluations that leverage the expertise and experience of graduated countries to encourage cross-learning.

Vaccination Utilization and Subnational Inequities during the COVID-19 Pandemic: An Interrupted Time-Series Analysis of Administrative Data across 12 Low- and Middle-Income Countries

BACKGROUND

During and after the SARS-CoV-2 (COVID-19) pandemic, many countries experienced declines in immunization that have not fully recovered to pre-pandemic levels. This study uses routine health facility immunization data to estimate variability between and within countries in post-pandemic immunization service recovery for BCG, DPT1, and DPT3.

METHODS

After adjusting for data reporting completeness and outliers, interrupted time series regression was used to estimate the expected immunization service volume for each subnational unit, using an interruption point of March 2020. We assessed and compared the percent deviation of observed immunizations from the expected service volume for March 2020 between and within countries.

RESULTS

Six countries experienced significant service volume declines for at least one vaccine as of October 2022. The shortfall in BCG service volume was ~6% (95% CI -1.2%, -9.8%) in Guinea and ~19% (95% CI -16%, 22%) in Liberia. Significant cumulative shortfalls in DPT1 service volume are observed in Afghanistan (-4%, 95% CI -1%, -7%), Ghana (-3%, 95% CI -1%, -5%), Haiti (-7%, 95% CI -1%, -12%), and Kenya (-3%, 95% CI -1%, -4%). Afghanistan has the highest percentage of subnational units reporting a shortfall of 5% or higher in DPT1 service volume (85% in 2021 Q1 and 79% in 2020 Q4), followed by Bangladesh (2020 Q1, 83%), Haiti (80% in 2020 Q2), and Ghana (2022 Q2, 75%). All subnational units in Bangladesh experienced a 5% or higher shortfall in DPT3 service volume in the second quarter of 2020. In Haiti, 80% of the subnational units experienced a 5% or higher reduction in DPT3 service volume in the second quarter of 2020 and the third quarter of 2022.

CONCLUSIONS

At least one region in every country has a significantly lower-than-expected post-pandemic cumulative volume for at least one of the three vaccines. Subnational monitoring of immunization service volumes using disaggregated routine health facility information data should be conducted routinely to target the limited vaccination resources to subnational units with the highest inequities.

Building resilient cervical cancer prevention through gender-neutral HPV vaccination

The COVID-19 pandemic has disrupted HPV vaccination programmes worldwide. Using an agent-based model, EpiMetHeos, recently calibrated to Indian data, we illustrate how shifting from a girls-only (GO) to a gender-neutral (GN) vaccination strategy could improve the resilience of cervical cancer prevention against disruption of HPV vaccination. In the base case of 5-year disruption with no coverage, shifting from GO to GN strategy under 60% coverage (before disruption) would increase the resilience, in terms of cervical cancer cases still prevented in the disrupted birth cohorts per 100,000 girls born, by 2.8-fold from 107 to 302 cases, and by 2.2-fold from 209 to 464 cases under 90% coverage. Furthermore, shifting to GN vaccination helped in reaching the World Health Organization (WHO) elimination threshold. Under GO vaccination with 60% coverage, the age-standardised incidence rate of cervical cancer in India in the long term with vaccination decreased from 11.0 to 4.7 cases per 100,000 woman-years (above threshold), as compared to 2.8 cases (below threshold) under GN with 60% coverage and 2.4 cases (below threshold) under GN with 90% coverage. In conclusion, GN HPV vaccination is an effective strategy to improve the resilience to disruption of cancer prevention programmes and to enhance the progress towards cervical cancer elimination.

Protective Effect of BCG and Neutrophil-to-Lymphocyte Ratio on Latent Tuberculosis in End Stage Renal Disease

INTRODUCTION

Bacillus Calmette-Guérin (BCG) vaccination has been reported to be protective against latent tuberculosis infection (LTBI) in the general population. The aim of this study was to investigate the protective effect of BCG vaccination against LTBI in adult patients with end-stage renal disease (ESRD) and renal transplants.

METHODS

Patients aged ≥ 20 years with ESRD who received hemodialysis (HD), peritoneal dialysis (PD) or kidney transplant were enrolled from January 2012 to December 2019 at a medical center and a regional hemodialysis center. Patients with active tuberculosis (TB), previously treated TB, active immunosuppressant therapy or human immunodeficiency virus infection were excluded. LTBI status was determined by QuantiFERON-TB Gold In-tube (QFT-GIT).

RESULTS

After the exclusion of indeterminate results of QFT-GIT, 517 participants were enrolled and 97 (18.8%) were identified as having LTBI. Participants with LTBI were older (55.1 ± 11.4 vs. 48.5 ± 14.6 years, p < 0.001) and had a significantly higher proportion receiving HD than those without LTBI (70.1% vs. 56.7%, p = 0.001). The percentage with BCG scars was higher in the non-LTBI group than in the LTBI group (94.8% vs. 81.4%, p < 0.001), whereas the neutrophil-to-lymphocyte ratio (NLR) (≥ 2.68) was significantly higher in the LTBI group (62.8% vs. 45.5%, p = 0.02). By multivariate logistic regression analysis, presence of BCG scar and high NLR were independent protective factors against LTBI [adjusted OR: 0.19 (0.063-0.58, p = 0.001) and 0.50 (0.28-0.89, p = 0.02)].

CONCLUSION

The prevalence of LTBI was as high as 18.8% in patients with end-stage kidney disease or kidney transplant. BCG vaccination and high NLR might have protective effects against LTBI in patients with renal failure or transplant.

Measuring National Immunization System Performance: A Systematic Assessment of Available Resources

BACKGROUND

Vaccination coverage is widely used to assess immunization performance but, on its own, provides insufficient information to drive improvements. Assessing the performance of underlying components of immunization systems is less clear, with several monitoring and evaluation (M&E) resources available for use in different operational settings and for different purposes. We studied these resources to understand how immunization system performance is measured.

METHODS

We reviewed peer-reviewed and gray literature published since 2000 to identify M&E resources that include national-level indicators measuring the performance of immunization systems or their components (governance, financing, regulation, information systems, vaccine logistics, workforce, service delivery, and demand generation). We summarize indicators by the system components or outcomes measured and describe findings narratively.

RESULTS

We identified 20 resources to monitor immunization program objectives and guide national strategic decision-making, encompassing 631 distinct indicators. Indicators for immunization program outcomes comprised the majority (124/631 [19.7%]), largely vaccination coverage (110/124 [88.7%]). Almost all resources (19/20 [95%]) included indicators for vaccine logistics (83/631 [13.2%]), and those for regulation (19/631 [3.0%]) and demand generation (28/631 [4.4%]) were least common. There was heterogeneity in how information systems (92/563 [14.6%]) and workforce (47/631 [7.4%]) were assessed across resources. Indicators for vaccination coverage in adults, data use in decision-making, equity and diversity, effectiveness of safety surveillance, and availability of a public health workforce were notably lacking.

CONCLUSIONS

Between the resources identified in this review, we identified considerable variability and gaps in indicators assessing the performance of some immunization system components. Given the multitude of indicators, policymakers may be better served by tailoring evaluation resources to their specific context to gain useful insight into health system performance and improve data use in decision-making for immunization programs.

Protection against tuberculosis achieved by dissolving microneedle patches loaded with live Mycobacterium paragordonae in a BCG prime-boost strategy

Introduction

Skin vaccination using dissolving microneedle patch (MNP) technology for transdermal delivery is a promising vaccine delivery strategy to overcome the limitations of the existing vaccine administration strategies using syringes. To improve the traditional microneedle mold fabrication technique, we introduced droplet extension (DEN) to reduce drug loss. Tuberculosis remains a major public health problem worldwide, and BCG revaccination had failed to increase the protective efficacy against tuberculosis. We developed an MNP with live Mycobacterium paragordonae (Mpg) (Mpg-MNP) as a candidate of tuberculosis booster vaccine in a heterologous prime-boost strategy to increase the BCG vaccine efficacy.

Materials and methods

The MNPs were fabricated by the DEN method on a polyvinyl alcohol mask film and hydrocolloid-adhesive sheet with microneedles composed of a mixture of mycobacteria and hyaluronic acid. We assessed the transdermal delivery efficiency by comparing the activation of the dermal immune system with that of subcutaneous injection. A BCG prime Mpg-MNP boost regimen was administered to a mouse model to evaluate the protective efficacy against M. tuberculosis.

Results

We demonstrated the successful transdermal delivery achieved by Mpg-MNP compared with that observed with BCG-MNP or subcutaneous vaccination via an increased abundance of MHCII-expressing Langerin+ cells within the dermis that could migrate into draining lymph nodes to induce T-cell activation. In a BCG prime-boost regimen, Mpg-MNP was more protective than BCG-only immunization or BCG-MNP boost, resulting in a lower bacterial burden in the lungs of mice infected with virulent M. tuberculosis. Mpg-MNP-boosted mice showed higher serum levels of IgG than BCG-MNP-boosted mice. Furthermore, Ag85B-specific T-cells were activated after BCG priming and Mpg-MNP boost, indicating increased production of Th1-related cytokines in response to M. tuberculosis challenge, which is correlated with enhanced protective efficacy.

Discussion

The MNP fabricated by the DEN method maintained the viability of Mpg and achieved effective release in the dermis. Our data demonstrate a potential application of Mpg-MNP as a booster vaccine to enhance the efficacy of BCG vaccination against M. tuberculosis. This study produced the first MNP loaded with nontuberculous mycobacteria (NTM) to be used as a heterologous booster vaccine with verified protective efficacy against M. tuberculosis.

COVID-19 Impact on DTP Vaccination Trends in Africa: A Joinpoint Regression Analysis

BACKGROUND

Deaths due to vaccine-preventable diseases are one of the leading causes of death among African children. Vaccine coverage is an essential measure to decrease infant mortality. The COVID-19 pandemic has affected the healthcare system and may have disrupted vaccine coverage.

METHODS

DTP third doses (DTP3) Vaccine Coverage was extracted from UNICEF databases from 2012 to 2021 (the last available date). Joinpoint regression was performed to detect the point where the trend changed. The annual percentage change (APC) with 95% confidence intervals (95% CI) was calculated for Africa and the regions. We compared DTP3 vaccination coverage in 2019-2021 in each country using the Chi-square test.

RESULT

During the whole period, the vaccine coverage in Africa increased with an Annual Percent change of 1.2% (IC 95% 0.9-1.5): We detected one joinpoint in 2019. In 2019-2021, there was a decrease in DTP3 coverage with an APC of -3.5 (95% -6.0; -0,9). (p < 0.001). Vaccination rates decreased in many regions of Sub-Saharan Africa, especially in Eastern and Southern Africa. There were 26 countries (Angola, Cabo Verde, Comoros, Congo, Côte d'Ivoire, Democratic Republic of the Congo, Djibouti, Ethiopia, Eswatini, The Gambia, Guinea-Bissau, Liberia, Madagascar, Malawi, Mauritania, Mauritius, Mozambique, Rwanda, Senegal, Seychelles, Sierra Leone, Sudan, Tanzania, Togo, Tunisia, Uganda, and Zimbabwe) where the vaccine coverage during the two years decreased. There were 10 countries (Angola, Cabo Verde, Comoros, Democratic Republic of the Congo, Eswatini, The Gambia, Mozambique, Rwanda, Senegal, and Sudan) where the joinpoint regression detected a change in the trend.

CONCLUSIONS

COVID-19 has disrupted vaccine coverage, decreasing it all over Africa.

Diagnosing viral encephalitis and emerging concepts

PURPOSE OF REVIEW

This review offers a contemporary clinical approach to the diagnosis of viral encephalitis and discusses recent advances in the field. The neurologic effects of coronaviruses, including COVID-19, as well as management of encephalitis are not covered in this review.

RECENT FINDINGS

The diagnostic tools for evaluating patients with viral encephalitis are evolving quickly. Multiplex PCR panels are now in widespread use and allow for rapid pathogen detection and potentially reduce empiric antimicrobial exposure in certain patients, while metagenomic next-generation sequencing holds great promise in diagnosing challenging and rarer causes of viral encephalitis. We also review topical and emerging infections pertinent to neuroinfectious disease practice, including emerging arboviruses, monkeypox virus (mpox), and measles.

SUMMARY

Although etiological diagnosis remains challenging in viral encephalitis, recent advances may soon provide the clinician with additional tools. Environmental changes, host factors (such as ubiquitous use of immunosuppression), and societal trends (re-emergence of vaccine preventable diseases) are likely to change the landscape of neurologic infections that are considered and treated in clinical practice.

Estimating global and regional between-country inequality in routine childhood vaccine coverage in 195 countries and territories from 2019 to 2021: a longitudinal study

Background

Global routine childhood vaccine coverage has plateaued in recent years, and the COVID-19 pandemic further disrupted immunisation services. We estimated global and regional inequality of routine childhood vaccine coverage from 2019 to 2021, particularly assessing the impacts of the COVID-19 pandemic.

Methods

We used longitudinal data for 11 routine childhood vaccines from the WHO-UNICEF Estimates of National Immunization Coverage (WUENIC), including 195 countries and territories in 2019-2021. The slope index of inequality (SII) and relative index of inequality (RII) of each vaccine were calculated through linear regression to express the difference in coverage between the top and bottom 20% of countries at the global and regional levels. We also explored inequalities of routine childhood vaccine coverage by WHO regions and unvaccinated children by income groups.

Findings

Globally between January 1, 2019 and December 31, 2021, most childhood vaccines showed a declining trend in coverage, and therefore an increasing number of unvaccinated children, especially in low-income and lower-middle-income countries. Between-country inequalities existed for all 11 routine childhood vaccine coverage indicators. The SII for the third dose of diphtheria-tetanus-pertussis-containing vaccine (DTP3) coverage was 20.1 percentage points (95% confidence interval: 13.7, 26.5) in 2019, and rose to 23.6 (17.5, 30.0) in 2020 and 26.9 (20.0, 33.8) in 2021. Similar patterns were found for RII results and in other routine vaccines. In 2021, the second dose of measles-containing vaccine (MCV2) coverage had the highest global absolute inequality (31.2, [21.5-40.8]), and completed rotavirus vaccine (RotaC) coverage had the lowest (7.8, [-3.9, 19.5]). Among six WHO regions, the European Region consistently had the lowest inequalities, and the Western Pacific Region had the largest inequalities for many indicators, although both increased from 2019 to 2021.

Interpretation

Global and regional inequalities of routine childhood vaccine coverage persisted and substantially increased from 2019 to 2021. These findings reveal economic-related inequalities by vaccines, regions, and countries, and underscore the importance of reducing such inequalities. These inequalities were widened during the COVID-19 pandemic, resulting in even lower coverage and more unvaccinated children in low-income countries.

Funding

Bill & Melinda Gates Foundation.

Pneumococcal Disease: Global Disease Prevention Strategies with a Focus on the Challenges in Iraq

Pneumococcal disease is a global public health concern that significantly contributes to clinical disease burden and economic burden. Patients frequently afflicted are young children and older adults, as well as the immunocompromised population. Immunization is the most effective public health strategy to combat pneumococcal disease and several vaccine formulations have been developed in this regard. Although vaccines have had a significant global impact in reducing pneumococcal disease, there are several barriers to its success in Iraq. The war and conflict situation, increasing economic crises and poverty, poor vaccine accessibility in the public sector, and high vaccine costs are a few of the major obstacles that impede a successful immunization program. The last reported third dose pneumococcal conjugate vaccine coverage for Iraq was 37% in 2019, which is expected to reduce even further owing to the COVID-19 pandemic. Thus, strategies and policies to improve pneumococcal vaccine availability and coverage need to be strengthened to achieve maximum benefits of immunization. In the current review, we provide an overview of the existing knowledge on pneumococcal disease-prevention strategies across the globe. The main aim of this manuscript is to discuss the current status and challenges of pneumococcal vaccination in Iraq as well as the strategies to prevent pneumococcal infections.

Cost-Effectiveness Analyses of Digital Health Technology for Improving the Uptake of Vaccination Programs: Systematic Review

BACKGROUND

Vaccination is the most effective strategy to prevent infectious diseases, yet vaccination coverage has not reached the target level. To promote vaccination uptake, digital health interventions (DHIs) have been used in various vaccination programs.

OBJECTIVE

This study aimed to perform a systematic review of the cost-effectiveness analyses of DHIs for the improvement of the uptake of vaccination programs.

METHODS

A literature review was conducted in MEDLINE (Ovid), Embase (Ovid), APA PsycINFO (Ovid), Web of Science, Scopus, CINAHL Ultimate (EBSCOhost), Center for Review and Dissemination, and Institute for IEEE Xplore up to October 2022. Health economic evaluations that met the following inclusion criteria were included: (1) adult or pediatric vaccination programs; (2) interventions delivered through digital technology; (3) full-scale health economic analyses including cost-effectiveness, cost-utility, cost-benefit, or cost-consequence analyses; and (4) evaluations conducted by model-based or trial-based analyses. The quality of each included study was evaluated using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS).

RESULTS

The systematic review included 7 studies. Four of the cost-effectiveness studies were conducted by model-based analyses, and 3 were trial-based analyses. One study reported the additional cost per quality-adjusted life years (QALYs) gained, whereas 6 studies reported the additional cost per individual vaccinated (or return case). The vaccines targeted the human papillomavirus (HPV) vaccine, influenza vaccination, measles-mumps-rubella (MMR) vaccine, and children immunization at different ages. The DHIs were delivered by television campaign, web-based decision aid, SMS text message, telephone, and computer-generated recall letters. The studies were classified as very good (n=5) and good (n=2) qualities. One study concluded that the DHI was cost-saving, and 6 studies concluded that the DHI was cost-effective.

CONCLUSIONS

This study is the first systematic review on cost-effectiveness analyses of DHIs to improve vaccination uptake. All included studies have good to very good quality on study assessment and reported the DHIs to be cost-saving or cost-effective in the improvement of vaccination uptake.

Using geographic information system to track children and optimize immunization coverage and equity in Karachi, Pakistan

BACKGROUND

Despite the potential of geospatial technologies to track and monitor coverage, they are underutilized for guiding immunization program strategy and implementation, especially in low-and-middle-income countries. We conducted geospatial analysis to explore the geographic and temporal trends of immunization coverage, and examined the pattern of immunization service access (outreach and facility based) by children.

METHODOLOGY

We extracted data to analyze coverage rates across different dimensions (by enrolment year, birth year and vaccination year) from 2018 till 2020 in Karachi, Pakistan using the Sindh Electronic Immunization Registry (SEIR). We conducted geospatial analysis to assess variation in coverage rates of BCG, Pentavalent (Penta)-1, Penta-3, and Measles-1 vaccines using Government targets. We also analyzed the proportion of children receiving their routine vaccinations at fixed centers and outreach and examined whether children received vaccinations at the same or multiple immunization centers.

RESULTS

A total of 1,298,555 children were born, enrolled or vaccinated from 2018 till 2020. At the district level, analysis by enrollment and birth year showed coverage increased between 2018 and 2019 and declined in 2020, while analysis by vaccination year showed consistent increase in coverage. However, micro-geographic analysis revealed pockets where coverage persistently declined. Notably 27/168, 39/168 and 3/156 Union councils showed consistently declining coverage when analyzing by enrollment, birth and vaccination year respectively. More than half (52.2%, 678,280/1,298,555) of the children received all their vaccinations exclusively through fixed centers and, 71.7% (499,391/696,701) received all vaccinations from the same centers.

CONCLUSION

Despite overall improving vaccination coverage between 2018 and 2020, certain geographic areas have consistently declining coverage rates, which is detrimental for equity. Making immunization inequities visible through geospatial analysis is the first step to ensure resources are allocated optimally. Our study provides impetus for immunization programs to develop and invest in geospatial technologies, harnessing its potential for improved coverage and equity.

Hepatitis B

Hepatitis B virus (HBV) infection is a major public health problem, with an estimated 296 million people chronically infected and 820 000 deaths worldwide in 2019. Diagnosis of HBV infection requires serological testing for HBsAg and for acute infection additional testing for IgM hepatitis B core antibody (IgM anti-HBc, for the window period when neither HBsAg nor anti-HBs is detected). Assessment of HBV replication status to guide treatment decisions involves testing for HBV DNA, whereas assessment of liver disease activity and staging is mainly based on aminotransferases, platelet count, and elastography. Universal infant immunisation, including birth dose vaccination is the most effective means to prevent chronic HBV infection. Two vaccines with improved immunogenicity have recently been approved for adults in the USA and EU, with availability expected to expand. Current therapies, pegylated interferon, and nucleos(t)ide analogues can prevent development of cirrhosis and hepatocellular carcinoma, but do not eradicate the virus and rarely clear HBsAg. Treatment is recommended for patients with cirrhosis or with high HBV DNA levels and active or advanced liver disease. New antiviral and immunomodulatory therapies aiming to achieve functional cure (ie, clearance of HBsAg) are in clinical development. Improved vaccination coverage, increased screening, diagnosis and linkage to care, development of curative therapies, and removal of stigma are important in achieving WHO's goal of eliminating HBV infection by 2030.

Measles clinical presentation, hospitalization and vaccination status among children in a community-wide outbreak

BACKGROUND

In 2018-2019, a measles outbreak emerged in Israel (4158 notified cases). We aimed to evaluate the measles characteristics and the vaccination status among children during the outbreak.

METHODS

We performed a cross-sectional study of measles cases in children under 18 years, residing in the Jerusalem district (2254 notified measles cases, June 2018-May 2019). The variables included: clinical symptoms (fever, rash, cough, coryza, conjunctivitis), hospitalizations and child's vaccination status. The national measles vaccination schedule includes two vaccine doses (at ages 12 months and 6 years).

RESULTS

Children, under 18 years, comprised 79% (1782/2254) of the notified measles cases. The hospitalization rate was 6.6%. There was one fatality. The measles vaccination status was analyzed by age groups. Infants under 12 months (n = 425) were excluded. Children aged 1-5 years (n = 785) and 6-17 years (n = 572) were expected to receive 1 and 2 measles vaccine doses, respectively. Most (88%) children (1-17 years) were unvaccinated, 138 received 1 measles vaccine dose and 24 received 2 doses. Of children aged 1-5 years 106 (13.5%) received 1 vaccine dose and were compared to unvaccinated children. Vaccinated children showed lower rates of clinical symptoms and lower risk for hospitalization compared to unvaccinated children (Odds ratio: OR = 4.8, 95%CI 1.12-20.2). Vaccine effectiveness of 79% was estimated for one measles vaccine dose against hospitalization.

CONCLUSIONS

Data on vaccine effectiveness reflect how well vaccines protect children against infection and morbidity. We evaluated the real-world effectiveness of measles vaccine, in an outbreak setting, and showed reduced morbidity in once-vaccinated children.

Hepatitis B Virus in West African Children: Systematic Review and Meta-Analysis of HIV and Other Factors Associated with Hepatitis B Infection

While Hepatitis B virus (HBV) and the human immunodeficiency virus (HIV) are endemic in West Africa, the prevalence of HBV/HIV coinfection and their associated risk factors in children remains unclear. In this review, we sought to assess HBsAg seroprevalence among 0- to 16-year-olds with and without HIV in West African countries and the risk factors associated with HBV infection in this population. Research articles between 2000 and 2021 that reported the prevalence of HBV and associated risk factors in children in West Africa were retrieved from the literature using the Africa Journals Online (AJOL), PubMed, Google Scholar, and Web of Science databases as search tools. StatsDirect, a statistical software, was used to perform a meta-analysis of the retained studies. HBV prevalence and heterogeneity were then assessed with a 95% confidence interval (CI). Publication bias was evaluated using funnel plot asymmetry and Egger's test. Twenty-seven articles conducted across seven West African countries were included in this review. HBV prevalence among persons aged 0 to 16 years was 5%, based on the random analysis, given the great heterogeneity of the studies. By country, the highest prevalence was observed in Benin (10%), followed by Nigeria (7%), and Ivory Coast (5%), with Togo (1%) having the lowest. HBV prevalence in an HIV-infected population of children was (9%). Vaccinated children had lower HBV prevalence (2%) than unvaccinated children (6%). HBV prevalence with a defined risk factor such as HIV co-infection, maternal HBsAg positivity, undergoing surgery, scarification, or being unvaccinated ranged from 3-9%. The study highlights the need to reinforce vaccination of newborns, screening for HBV, and HBV prophylaxis among pregnant women in Africa, particularly in West Africa, to achieve the WHO goal of HBV elimination, particularly in children.

Empowering Health Workers to Build Public Trust in Vaccination: Experience from the International Pediatric Association's Online Vaccine Trust Course, 2020-2021

BACKGROUND

The quality of interactions between health workers (HWs) and caregivers is key in vaccine acceptance. To optimize this, HWs need knowledge about best vaccine communication practices in person and on social media. Most pre-service curricula do not include such approaches. COVID-19 necessitated the International Pediatric Association (IPA) to shift from in-person train the trainer workshops to developing an online Vaccine Trust Course to address these gaps.

METHOD

The seven-module, 8-hour Vaccine Trust Course was offered online in seven languages and promoted globally. Course outcomes for participants between September 1, 2020 and September 30, 2021 were assessed using enrollment, participation, and completion data; pre-and post-training surveys of attitudes, knowledge, and practice skills; and follow-up practice surveys 3 months post course completion.

RESULTS

Of the 4,926 participants across 137 countries who registered; 2,381 (48.3 %) started the course, with 1,217 (51.1 %) completing. The majority were 25 - 39 years (57 %), female (57 %), and in pediatrics (70 %); 31 % came from India. 62 % of completers rated course structure/design as excellent, 36 % as good. Over 80 % rated the content as the most valuable aspect. Three months post training, 61 % HWs reported increased empathy towards caregivers, confidence while counseling and increased vaccine acceptance amongst their patients. 21 % identified the course as the only factor in these positive changes.

CONCLUSION

Shifting from face-to-face to online training due to the COVID-19 pandemic helped increase the global reach of HWs course engagement and uptake. Trained HWs reported increased empathy towards caregivers and confidence while counseling and increased patient vaccine acceptance.

Use of catch-up vaccinations in the second year of life (2YL) platform to close immunity gaps: A secondary DHS analysis in Pakistan, Philippines, and South Africa

BACKGROUND

Immunity gaps caused by COVID-19-related disruptions highlight the importance of catch-up vaccination. Number of countries offering vaccines in second year of life (2YL) has increased, but use of 2YL for catch-up vaccination has been variable. We assessed pre-pandemic use of 2YL for catch-up vaccination in three countries (Pakistan, the Philippines, and South Africa), based on existence of a 2YL platform (demonstrated by offering second dose of measles-containing vaccine (MCV2) in 2YL), proportion of card availability, and geographical variety.

METHODS

We conducted a secondary data analysis of immunization data from Demographic and Health Surveys (DHS) in Pakistan (2017-2018), the Philippines (2017), and South Africa (2016). We conducted time-to-event analyses for pentavalent vaccine (diphtheria-tetanus-pertussis-Hepatitis B-Haemophilus influenzae type b [Hib]) and MCV and calculated use of 2YL and MCV visits for catch-up vaccination.

RESULTS

Among 24-35-month-olds with documented dates, coverage of third dose of pentavalent vaccine increased in 2YL by 2%, 3%, and 1% in Pakistan, Philippines, and South Africa, respectively. MCV1 coverage increased in 2YL by 5% in Pakistan, 10% in the Philippines, and 3% in South Africa. In Pakistan, among 124 children eligible for catch-up vaccination of pentavalent vaccine at time of a documented MCV visit, 45% received a catch-up dose. In the Philippines, among 381 eligible children, 38% received a pentavalent dose during an MCV visit. In South Africa, 50 children were eligible for a pentavalent vaccine dose before their MCV1 visit, but only 20% received it; none with MCV2.

CONCLUSION

Small to modest vaccine coverage improvements occurred in all three countries through catch-up vaccination in 2YL but many missed opportunities for vaccination continue to occur. Using the 2YL platform can increase coverage and close immunity gaps, but immunization programmes need to change policies, practices, and monitor catch-up vaccination to maximize the potential.

The Reemergence of Measles

OBJECTIVES

Present-day pathologists may be unfamiliar with the histopathologic features of measles, which is a reemerging disease. Awareness of these features may enable early diagnosis of measles in unsuspected cases, including those with an atypical presentation. Using archived tissue samples from historic patients, a unique source of histopathologic information about measles and other reemerging infectious diseases, we performed a comprehensive analysis of the histopathologic features of measles seen in commonly infected tissues during prodrome, active, and late phases of the disease.

METHODS

Subspecialty pathologists analyzed H&E-stained slides of specimens from 89 patients accessioned from 1919 to 1998 and correlated the histopathologic findings with clinical data.

RESULTS

Measles caused acute and chronic histopathologic changes, especially in the respiratory, lymphoid (including appendix and tonsils), and central nervous systems. Bacterial infections in lung and other organs contributed significantly to adverse outcomes, especially in immunocompromised patients.

CONCLUSIONS

Certain histopathologic features, especially Warthin-Finkeldey cells and multinucleated giant cells without inclusions, allow pathologists to diagnose or suggest the diagnosis of measles in unsuspected cases.

Lynch syndrome cancer vaccines: A roadmap for the development of precision immunoprevention strategies

Hereditary cancer syndromes (HCS) account for 5~10% of all cancer diagnosis. Lynch syndrome (LS) is one of the most common HCS, caused by germline mutations in the DNA mismatch repair (MMR) genes. Even with prospective cancer surveillance, LS is associated with up to 50% lifetime risk of colorectal, endometrial, and other cancers. While significant progress has been made in the timely identification of germline pathogenic variant carriers and monitoring and early detection of precancerous lesions, cancer-risk reduction strategies are still centered around endoscopic or surgical removal of neoplastic lesions and susceptible organs. Safe and effective cancer prevention strategies are critically needed to improve the life quality and longevity of LS and other HCS carriers. The era of precision oncology driven by recent technological advances in tumor molecular profiling and a better understanding of genetic risk factors has transformed cancer prevention approaches for at-risk individuals, including LS carriers. MMR deficiency leads to the accumulation of insertion and deletion mutations in microsatellites (MS), which are particularly prone to DNA polymerase slippage during DNA replication. Mutations in coding MS give rise to frameshift peptides (FSP) that are recognized by the immune system as neoantigens. Due to clonal evolution, LS tumors share a set of recurrent and predictable FSP neoantigens in the same and in different LS patients. Cancer vaccines composed of commonly recurring FSP neoantigens selected through prediction algorithms have been clinically evaluated in LS carriers and proven safe and immunogenic. Preclinically analogous FSP vaccines have been shown to elicit FSP-directed immune responses and exert tumor-preventive efficacy in murine models of LS. While the immunopreventive efficacy of "off-the-shelf" vaccines consisting of commonly recurring FSP antigens is currently investigated in LS clinical trials, the feasibility and utility of personalized FSP vaccines with individual HLA-restricted epitopes are being explored for more precise targeting. Here, we discuss recent advances in precision cancer immunoprevention approaches, emerging enabling technologies, research gaps, and implementation barriers toward clinical translation of risk-tailored prevention strategies for LS carriers. We will also discuss the feasibility and practicality of next-generation cancer vaccines that are based on personalized immunogenic epitopes for precision cancer immunoprevention.

Responses to COVID-19 Threats: an Evolutionary Psychological Analysis

Responses to COVID-19 public health interventions have been lukewarm. For example, only 64% of the US population has received at least two vaccinations. Because most public health interventions require people to behave in ways that are evolutionarily novel, evolutionary psychological theory and research on mismatch theory, the behavioral immune system, and individual differences can help us gain a better understanding of how people respond to public health information. Primary sources of threat information during the pandemic (particularly in early phases) were geographic differences in morbidity and mortality statistics. We argue that people are unlikely to respond to this type of evolutionarily novel information, particularly under conditions of high uncertainty. However, because individual differences affect threat perceptions, some individual differences will be associated with threat responses. We conducted two studies (during Phase 1 and 2 years later), using data from primarily public sources. We found that state-level COVID-19 morbidity and mortality rates had no relationship with mental health symptoms (an early indicator of how people were responding to the pandemic), suggesting that people-in general-were not attending to this type of information. This result is consistent with the evolutionary psychological explanation that statistical information is likely to have a weak effect on the behavioral immune system. We also found that individual differences (neuroticism, IQ, age, and political ideology) affected how people responded to COVID-19 threats, supporting a niche-picking explanation. We conclude with suggestions for future research and suggestions for improving interventions and promoting greater compliance.

Determinants of basic childhood vaccination coverage in European and OECD countries

Vaccination coverage varies between countries and over time. Using official databases, we extracted data on 50 national-level immunization, socio-economic, demographic, healthcare, and cultural factors, and the uptake of the third dose of diphtheria toxoid, tetanus toxoid, and pertussis vaccines (DTP3) and the first dose of measles-containing vaccines (MCV1) for 61 countries between 1990 and 2019. The main branch of the analysis included all covariates, while a secondary branch excluded life-expectancy and child mortality. The statistical analysis was completed in three stages: a variable-selection stage via random forests; multilevel multiple imputation for missing data in the reduced dataset; and generalized estimating equations (GEE) over all imputed datasets with pooled results. Less than 20 covariates were retained after variable-selection. Among a relatively small number of statistically significant (p-value <.05) effects in the pooled GEE results of our main branch, under-5 mortality and long-term orientation culture showed negative associations with both uptake outcomes and GDP per capita a positive association. For MCV1, whether a second dose was integrated into routine immunization appeared as the overall strongest negative correlate. In the secondary analytical branch, results were largely consistent, with a few additional statistically significant effects emerging, mainly related to immunization and healthcare system characteristics. These insights improve our understanding of the main factors influencing vaccine uptake, some of which are broadly contextual (e.g., GDP, socio-cultural factors), requiring bespoke vaccine program approaches, in order to maximize childhood vaccine uptake over time.

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).

Mathematical Analysis of an SIVRWS Model for Pertussis with Waning and Naturally Boosted Immunity

This work aims mainly to study the controllability of pertussis infection in the presence of waning and natural booster of pertussis immunity and to study their impact on the overall dynamics and disease outcomes. Therefore, an SIVRWS (Susceptible-Infected-Vaccinated-Recovered-Waned-Susceptible) model for pertussis infection spread in a demographically stationary, homogeneous, and fully symmetric mixing population is introduced. The model has been mathematically analyzed, where both equilibrium and stability analyses have been established, and uniform persistence of the model has been shown. The conditions on model parameters that ensure effective control of the infection have been derived. The effects of the interplay between waning and boosting pertussis immunity by re-exposure to Bordetella pertussis and vaccination on the dynamics have been investigated. The analytical results have been numerically confirmed and explained. The analysis reveals that ignoring the natural booster of immunity overestimates the endemic prevalence of the infection. Moreover, ignoring the differential susceptibility between secondary and primary susceptible individuals overestimates the critical vaccination coverage required to eliminate the infection. Moreover, the shorter the period of immunity acquired by either vaccination or experiencing natural infection, the higher the reproduction number and the endemic prevalence of infection, and therefore, the higher the effort needed to eliminate the infection.