BACKGROUND: Reducing childhood mortality by curtailing the incidence of vaccine preventable diseases is contingent upon a robust and high-performing routine immunization system. According to the available data, the full immunization coverage (FIC) in the state of Bihar (India) has reached ~ 71%. While the government aspires to reach 90% FIC, a systematic evidence-based investigation of the reasons behind underimmunization as well as the identification of drivers and enablers to reach and sustain 90% FIC is critical. This study aimed to review the factors leading to underimmunized children in the state of Bihar and develop a forward-looking roadmap to reach and sustain 90% FIC by adopting a system strengthening approach.
METHODS: We conducted a desk review, followed by extensive stakeholder interviews and field visits to document and analyze the data and evidence relevant to routine immunization system performance in the state of Bihar. The stakeholders included the State Immunization Officer, District Immunization Officers, Block-level health officials, representatives from development agencies, healthcare workers, and caregivers. A total of eighty-six structured interviews were conducted, which included qualitative and quantitative parameters.
RESULTS: While positive results were observed from the assessment of Bihar\'s immunization system, the implementation of targeted strategies for supply, service delivery and demand can provide a means to achieve FIC of 90%. The roadmap developed by the Government of Bihar enlists 40 + interventions across key thematic areas and has been prioritized over a 5-year time horizon as short, medium, and long-term milestones to achieve 90% FIC. These interventions include strengthening the data availability and quality, improving the governance and review mechanism, augmenting the capacity of health workers involve with immunization programme, and initiatives to increase demand for immunization services.
CONCLUSIONS: The Bihar\'s Immunization Roadmap development project work follows a methodical approach to assess and identify intervention to improve immunization coverage and can provide information and reference to other states and countries that are aiming to formulate similar action plans.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic disrupted routine childhood vaccination worldwide, especially at the beginning of the pandemic. After the emergence of variants of concern, particularly the Omicron variants, the number of COVID-19 cases significantly increased, especially in children. However, the impact of the Omicron variants on routine childhood vaccination is unknown.
METHODS: This retrospective observational study collected data on vaccines included in the Japanese national immunization program (NIP) of children 15 years or younger between 2016 and 2022 in Niigata, Japan. During the study period, hepatitis B virus vaccine and rotavirus vaccines were introduced to the NIP in October 2016 and October 2020, respectively. The monthly number of vaccine doses per eligible child population between 2020 and 2022 (pandemic period) was compared to the average number of vaccine doses in the corresponding month between 2016 and 2019 (pre-pandemic period). The effect of 8 surges of COVID-19 patients on trends in routine childhood vaccination was also analyzed.
RESULTS: The numbers of doses during the pre-Omicron pandemic period were comparable to the values administered before the pandemic. However, after the emergence of the Omicron variants, and especially after the surge of Omicron variant BA.5 in 2022, the number of vaccine doses declined. The decline was notable in second doses of MR vaccine at age 5-6 years by - 9.6 % and diphtheria-tetanus vaccine at ages 11-12 years by - 14.1 %.
CONCLUSIONS: Routine childhood immunization was significantly affected by the emergence of the Omicron variants most likely due to the facts that more candidates and their guardians contracted COVID-19, or were required isolation for close contacts. The findings highlight the importance of continued monitoring to maintain high coverage of routine childhood immunizations for controlling vaccine preventable diseases. A follow-up study should investigate changes in the number of declined vaccine doses during Omicron variant predominance.

BACKGROUND: The COVID-19 pandemic had a profound impact on healthcare systems and services, including routine immunization (RI). To date, there is limited information on the effects of the COVID-19 pandemic on RI in West African countries such as Sierra Leone, which had already experienced public health emergencies that disrupted its healthcare system. Here, we describe the impact of the COVID-19 pandemic on the RI of key antigens in Sierra Leone.
METHODS: We used vaccination data from the District Health Information System for BCG, measles-rubella 1 and 2, and pentavalent 1 and 3 antigens. We compared 2019, 2020, 2021, and 2022 annual coverage rates for the selected antigens at the national and district levels. We used the Pearson chi-square test to assess the difference between annual coverage rates between 2019 and 2020, 2020-2021, and 2021-2022.
RESULTS: National coverage rates for all antigens declined in 2019-2020, notably measles-rubella 1 and pentavalent 3 (-5.4% and - 4.9%). Between 2020 and 2021, there was an overall increase in coverage (+ 0.2% to + 2.5%), except for measles-rubella 2 (-1.8%). Measles-rubella antigens rebounded in 2021-2022, while others decreased between - 0.5 and - 1.9% in coverage. Overall, all district-level coverage rates in 2022 were lower than those in 2019. Most districts decreased between 2019 and 2022, though a few had a continuous increase; some had an increase/recovery between 2020 and 2021; some districts had recovered 2019 levels by 2022.
CONCLUSIONS: The COVID-19 pandemic impacted Sierra Leone\'s national BCG, measles-rubella, and pentavalent antigen immunization, which were not fully restored in 2022. Most districts experienced notable coverage declines during the pandemic, though a few reached or surpassed 2019 rates in 2022. Examining pandemic impact can benefit from a focus beyond the national level to identify vulnerable regions. Sierra Leone\'s post-pandemic RI reestablishment needs targeted strategies and continual investments for equitable access and coverage, as well as to prevent vaccine-preventable diseases.

Promoting vaccine acceptance and demand is an essential, yet often underrecognized component of ensuring that everyone has access to the full benefits of immunization. Convened by the Sabin Vaccine Institute, the Vaccination Acceptance Research Network (VARN) is a global network of multidisciplinary stakeholders driving strengthened vaccination acceptance, demand, and delivery. VARN works to advance and apply social and behavioral science insights, research, and expertise to the challenges and opportunities facing vaccination decision-makers. The second annual VARN conference, When Communities Lead, Global Immunization Succeeds, was held June 13-15, 2023, in Bangkok, Thailand. VARN2023 provided a space for the exploration and dissemination of a growing body of evidence, knowledge, and practice for driving action across the vaccination acceptance, demand, and delivery ecosystem. VARN2023 was co-convened by Sabin and UNICEF and co-sponsored by Gavi, the Vaccine Alliance. VARN2023 brought together 231 global, regional, national, sub-national, and community-level representatives from 47 countries. The conference provided a forum to share learnings and solutions from work conducted across 40+ countries. This article is a synthesis of evidence-based insights from the VARN2023 Conference within four key recommendations: (1) Make vaccine equity and inclusion central to programming to improve vaccine confidence, demand, and delivery; (2) Prioritize communities in immunization service delivery through people-centered approaches and tools that amplify community needs to policymakers, build trust, and combat misinformation; (3) Encourage innovative community-centric solutions for improved routine immunization coverage; and (4) Strengthen vaccination across the life course through building vaccine demand, service integration, and improving the immunization service experience. Insights from VARN can be applied to positively impact vaccination acceptance, demand, and uptake around the world.

BACKGROUND: In 2016, the Global Polio Eradication Initiative (GPEI) recommended the cessation of using type 2 oral poliovirus vaccine (OPV) and OPV, with countries having to switch from the trivalent to bivalent OPV (bOPV) with the addition of inactivated poliovirus vaccine (IPV) in their routine immunization schedule. The current GPEI strategy 2022-2026 includes a bOPV cessation plan and a switch to IPV alone or a combination of vaccine schedules in the future. The focus of our study was to evaluate the immunogenicity of monovalent OPV type 1 (mOPV1) with IPV and IPV-only schedules.
METHODS: This was a three-arm, multi-center randomized-controlled trial conducted in 2016-2017 in India. Participants, at birth, were randomly assigned to the bOPV-IPV (Arm A) or mOPV1-IPV (Arm B) or IPV (Arm C) schedules. Serum specimens collected at birth and at 14, 18, and 22 weeks old were analyzed with a standard microneutralization assay for all the three poliovirus serotypes.
RESULTS: The results of 598 participants were analyzed. The type 1 cumulative seroconversion rates four weeks after the completion of the schedule at 18 weeks were 99.5% (97.0-99.9), 100.0% (97.9-100.0), and 96.0% (92.0-98.1) in Arms A (4bOPV + IPV), B (4mOPV1 + IPV), and C (3IPV), respectively. Type 2 and type 3 seroconversions at 18 weeks were 80.0% (73.7-85.1), 76.9% (70.3-82.4); 93.2% (88.5-96.1), 100.0% (98.0-100.0); and 81.9% (75.6-86.8), 99.4% (96.9-99.9), respectively, in the three arms.
CONCLUSIONS: This study shows the high efficacy of different polio vaccines for serotype 1 in all three schedules. The type 1 seroconversion rate of mOPV1 is non-inferior to bOPV. All the vaccines provide high type-specific immunogenicity. The program can adopt the use of different vaccines or schedules depending on the epidemiology from time to time.

Infectious diseases pose a significant burden on the general population, particularly older adults who are more susceptible to severe complications. Immunization plays a crucial role in preventing infections and securing a healthier aging, but actual vaccination rates among older adults and frail individuals (OAFs) remains far from recommended targets. This study aims to collect and share good practices implemented in several Italian local health districts during the SARS-CoV-2 pandemic to ease routine immunization for OAFs. A 28-items questionnaire has been developed to collect information on organization aspect of immunization services and local good practices implemented before and during the SARS-CoV-2 pandemic. Twelve Public Health managers representative of 9 Italian Regions were further interviewed between January and March 2021. Despite literature suggests several effective interventions to increase vaccine demand, improve vaccine access, and enhance healthcare providers\' performance, our survey highlighted substantial heterogeneity in their implementation at local level. Seven good local practices have been identified and described: mass vaccination centers; vaccination mobile units; drive-through vaccination; co-administration; tailored pathways; cooperation among providers involved in vaccination; digitization. Our survey pointed out valuable strategies for enhancing routine immunization for OAFs. Providers should combine effective interventions adequate to their specific context and share good practices.

The COVID-19 pandemic caused a surge in the number of unimmunized and under-immunized children in Africa. The majority of unimmunized (or zero-dose) children live in hard-to-reach rural areas, urban slums, and communities affected by conflict where health facilities are usually unavailable or difficult to access. In these settings, people mostly rely on the informal health sector for essential health services. Therefore, to reduce zero-dose children, it is critical to expand immunization services beyond health facilities to the informal health sector to meet the immunization needs of children in underserved places. In this perspective article, we propose a framework for the expansion of immunization services through the informal health sector as one of the pillars for the big catch-up plan to improve coverage and equity. In African countries like Nigeria, Ethiopia, Tanzania, and the Democratic Republic of Congo, patent medicine vendors serve as an important informal health sector provider group, and thus, they can be engaged to provide immunization services. A hub-and-spoke model can be used to integrate patent medicine vendors into the immunization system. A hub-and-spoke model is a framework for organization design where services that are provided by a central facility (hub) are complimented by secondary sites (spokes) to optimize access to care. Systems thinking approach should guide the design, implementation, and evaluation of this model.

Childhood immunization is one of the most important public health interventions to reduce child morbidity and mortality. Reaching all children with full immunization services is critical to meet Nepal\'s commitment to Sustainable Development Goals (SDGs). This study aimed to identify factors affecting compliance with childhood immunization in children aged 16 to 36 months in Nepal. A community-based unmatched case-control study was conducted with 250 (83 cases and 167 controls) respondents in the Ilam district of Nepal. Respondents were randomly selected using a multi-stage cluster sampling technique. Data were collected using a structured questionnaire and analysed using SPSS version 16 statistical software. Bivariate and multivariate logistic regression analyses were done to identify the factors influencing compliance with childhood immunization of the sampled respondents. More than two-thirds (66.8%) of the sampled children were fully immunized, and 19.3% of the children defaulted to the Measles-Rubella vaccines. Only 19.2% of the respondents had good knowledge about the type of vaccine, and more than half (59.2%) of the respondents had a positive attitude towards immunization. Multivariate logistic regression analysis revealed that lack of knowledge about vaccines (AOR = 49.4, 95% CI = 12.94 to 188.59), father\'s level of education (AOR = 2.1, 95% CI = 1.05 to 4.30), not getting immunization on the day of the appointment (AOR = 4.8, 95% CI = 2.30 to 9.89), lack of knowledge about immunization schedule (AOR = 2.4, 95% CI = 1.14 to 4.84), and negative attitude towards immunization (AOR = 2.1, 95% CI = 1.03 to 4.19) were independently impeded on compliance on the childhood immunization. Targeted intervention in health promotion activities at the household level should be promoted and integrated immunization services into the existing primary health care services.

BACKGROUND: In Japan, routine administration to one-year-old children of two-dose immunization for varicella was introduced in October 2014. Object The object of this study was to report outbreaks of varicella under routine immunization at a nursery school and in its surrounding area using data of surrounding areas from the (Nursery) School Absenteeism Surveillance System. Then, we measured the effectiveness of routine two-dose immunization for varicella to onset. We tentatively assessed its severity in a nursery school.
METHODS: The study period extended from April 2017 through March 2018. The study area comprised Nursery school B and other nursery schools, and elementary and junior high schools in City A. Subjects in Nursery school B were 120 children. We analyzed vaccine effectiveness (VE) as an observational study and assessed severity using Fisher\'s exact test. We also assessed VE for severity using linear regression. Severity was defined as the length of nursery school absence attributable to varicella infection.
RESULTS: During the one month preceding a period of two weeks before the initial case at Nursery school B, there were 16 cases of varicella infection in nursery schools, 45 cases in elementary schools, and one case in junior high schools in City A. For children who had received one vaccine dose or more, VE was 48.1% for all ages and 49.2% among children three years old and older. No significant VE against infection was found. Vaccination using one dose or more can reduce severity significantly.
CONCLUSIONS: Because many nursery school children who had received two doses of vaccine were infected, VE was estimated as low in the nursery school and not significant. Although VE for severity with more than one dose was confirmed, a second dose might not reduce severity compared to one dose.

BACKGROUND: COVID-19 seriously impacted routine immunization (RI) in Iraq. Coverage declined to a 6-year low in 2021, and COVID-19 vaccination uptake was slow. In response, government implemented intensification of integrated immunization services (3IS), a nationwide approach comprising regular outreach sessions of COVID-19 vaccination and RI for children who had either missed doses or never commenced scheduled vaccination (zero-dose children). We describe the 3IS and its impact on vaccination coverage in Iraq.
METHODS: 3IS comprised new outreach sessions for urban and rural communities where administrative data suggested there were gaps in coverage. Groups of six personnel from each of 1,321 primary healthcare centres implemented six outreach sessions per month during February-November 2022. Community engagement was an integral component. We compared RI administrative data (2019-2022) and data reported during 3IS activities to assess its impact.
RESULTS: In total 4,189,859 vaccine doses were administered during 72,495 3IS outreach sessions, over one-fifth of 19,106,849 vaccine doses administered in Iraq over these 10 months. Among them, 957,874 (22.9 %) were COVID-19 vaccines, adding slightly to national coverage, and 3,231,985 (77.1 %) were RI vaccines, dramatically reducing zero-dose children, adding 18 %, 25 %, 21 %, and 31 % to 2022 penta1, penta3, measles first-dose and MMR1 vaccine coverage, and contributing to national coverage of 102.2 %, 94.5 %, 91.8 % and 96.3 % for these vaccines during February-November, respectively. Moreover, 3IS sessions delivered 133,528 doses of tetanus toxoid, 16,353 doses of adult HepB vaccine, and 315,032 vitamin A doses to eligible individuals.
CONCLUSIONS: In the context of global encouragement to integrate vaccination services, Iraq\'s 3IS approach enabled dramatic improvements in RI coverage, virtual elimination of zero-dose status among children born during the pandemic, and small improvements in COVID-19 and adult vaccination. Our findings provide lessons for future integrated primary care towards universal health coverage in Iraq, and for other countries yet to undertake integration.