Pub Date : 2026-02-06DOI: 10.3390/vaccines14020157
Reji Paalangara, Stephanie Gohin, Alexis Menard, Charlotte Amy, Wahiba Berrabah, Alexandra Rogue, Matthew A Getz, Aljawharah Alrubayyi, Simone Battella, Angelo Raggioli, Michela Gentile, Anthea Di Rita, Alessia Noto, Giuseppina Miselli, Fabiana Grazioli, Federico Napolitano, Dhurata Sowcik, Marco Soriani, Benjamin Chmielewski, Lebohang Molife, Vincent Muturi-Kioi, Azure Tariro Makadzange, Gaurav D Gaiha, Philippe Ancian, Jim Ackland, Antonella Folgori, Stefano Colloca, Stefania Capone
Background/Objectives: The rapid development of safe and efficacious vaccines is often hindered by extensive, mandated non-clinical safety evaluations in animals. With the aim to provide scientific evidence supporting a "vaccine platform approach", here we present the complete non-clinical studies for two investigational vaccines, GRAd-COV2 and GRAdHIVNE1, based on GRAd, a gorilla-derived group C adenoviral vector. Methods: The biodistribution of GRAd genomes following the intramuscular administration of the vaccines was assessed in rats by a sensitive qPCR method. Local tolerance and systemic toxic effects were evaluated in single- and repeated-dose toxicity studies in rabbits. Results: GRAd-COV2 and GRAdHIVNE1 were well-tolerated. Distribution was highly confined to the injection site and draining lymph nodes, and toxicity profile consisted of transient, non-adverse inflammatory responses, while the expected immune responses to the encoded antigens were successfully induced. Notably, both vaccines demonstrated a consistent safety profile despite transgene and backbone differences, comparable to other replication-defective adenoviral vectors. Conclusions: The established non-clinical safety profile of the GRAd platform provides a robust foundation for a more efficient and streamlined regulatory pathway. By leveraging this prior knowledge, future GRAd-based vaccines can achieve accelerated clinical development while fully adhering to the ethical principles of replacement, reduction, and refinement of animal use in research.
{"title":"Non-Clinical Safety of GRAd Vector-Based COVID-19 and HIV Vaccines Supports a Platform Regulatory Approach.","authors":"Reji Paalangara, Stephanie Gohin, Alexis Menard, Charlotte Amy, Wahiba Berrabah, Alexandra Rogue, Matthew A Getz, Aljawharah Alrubayyi, Simone Battella, Angelo Raggioli, Michela Gentile, Anthea Di Rita, Alessia Noto, Giuseppina Miselli, Fabiana Grazioli, Federico Napolitano, Dhurata Sowcik, Marco Soriani, Benjamin Chmielewski, Lebohang Molife, Vincent Muturi-Kioi, Azure Tariro Makadzange, Gaurav D Gaiha, Philippe Ancian, Jim Ackland, Antonella Folgori, Stefano Colloca, Stefania Capone","doi":"10.3390/vaccines14020157","DOIUrl":"10.3390/vaccines14020157","url":null,"abstract":"<p><p><b>Background/Objectives</b>: The rapid development of safe and efficacious vaccines is often hindered by extensive, mandated non-clinical safety evaluations in animals. With the aim to provide scientific evidence supporting a \"vaccine platform approach\", here we present the complete non-clinical studies for two investigational vaccines, GRAd-COV2 and GRAdHIVNE1, based on GRAd, a gorilla-derived group C adenoviral vector. <b>Methods</b>: The biodistribution of GRAd genomes following the intramuscular administration of the vaccines was assessed in rats by a sensitive qPCR method. Local tolerance and systemic toxic effects were evaluated in single- and repeated-dose toxicity studies in rabbits. <b>Results</b>: GRAd-COV2 and GRAdHIVNE1 were well-tolerated. Distribution was highly confined to the injection site and draining lymph nodes, and toxicity profile consisted of transient, non-adverse inflammatory responses, while the expected immune responses to the encoded antigens were successfully induced. Notably, both vaccines demonstrated a consistent safety profile despite transgene and backbone differences, comparable to other replication-defective adenoviral vectors. <b>Conclusions</b>: The established non-clinical safety profile of the GRAd platform provides a robust foundation for a more efficient and streamlined regulatory pathway. By leveraging this prior knowledge, future GRAd-based vaccines can achieve accelerated clinical development while fully adhering to the ethical principles of replacement, reduction, and refinement of animal use in research.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12944892/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147291076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.3390/vaccines14020156
Sherri Sheinfeld Gorin, Rebecca Hyman, Courtney Olson, Elizabeth Amber Fournier, Kaitlyn Yang, Diana Hanko, Hpv Review Working Group
The human papillomavirus (HPV) is the leading cause of cervical and oropharyngeal cancers. Vaccination can prevent over 90% of HPV-attributed cancers. Rural populations are less likely to initiate and complete HPV vaccinations than urban. The primary objective of this paper is to systematically examine the multilevel (child/youth, parent/caregiver, physician/team, healthcare organization, community, and policy) influences on HPV vaccine uptake in the rural US population. As a secondary aim, we seek to identify gaps in the research that could contribute to the development of more precise intervention approaches in this population. The study adds to the limited number of recent reviews on rural HPV vaccine uptake in the US.
Method: We conducted a systematic search of published empirical studies over 13 years (2010-2023), resulting in 1657 publications. The following databases were searched: Medline (OVID), Embase, CINAHL, PsychInfo, Cochrane, Sociological Abstracts, and Scopus using pre-specified inclusion criteria. Two reviewers independently coded 101 full texts; discrepancies were resolved by a third reviewer. The primary outcome was HPV vaccine uptake.
Results: Adolescents themselves were the most common foci of change. Barriers to rural HPV uptake included limited; vaccine awareness, access to vaccines for children vaccination sites, and primary care recommendations.
Conclusions: Tailored interventions to rural parents/caregivers could increase uptake of the vaccine. Provider training increases HPV vaccine recommendations; programs should also be targeted to rural school nurses, pharmacists, and dental care providers. Linking primary care practices and public health dissemination strategies are key.
{"title":"A Scoping Review of Influences on HPV Vaccine Uptake in the Rural US.","authors":"Sherri Sheinfeld Gorin, Rebecca Hyman, Courtney Olson, Elizabeth Amber Fournier, Kaitlyn Yang, Diana Hanko, Hpv Review Working Group","doi":"10.3390/vaccines14020156","DOIUrl":"10.3390/vaccines14020156","url":null,"abstract":"<p><p>The human papillomavirus (HPV) is the leading cause of cervical and oropharyngeal cancers. Vaccination can prevent over 90% of HPV-attributed cancers. Rural populations are less likely to initiate and complete HPV vaccinations than urban. The primary objective of this paper is to systematically examine the multilevel (child/youth, parent/caregiver, physician/team, healthcare organization, community, and policy) influences on HPV vaccine uptake in the rural US population. As a secondary aim, we seek to identify gaps in the research that could contribute to the development of more precise intervention approaches in this population. The study adds to the limited number of recent reviews on rural HPV vaccine uptake in the US.</p><p><strong>Method: </strong>We conducted a systematic search of published empirical studies over 13 years (2010-2023), resulting in 1657 publications. The following databases were searched: Medline (OVID), Embase, CINAHL, PsychInfo, Cochrane, Sociological Abstracts, and Scopus using pre-specified inclusion criteria. Two reviewers independently coded 101 full texts; discrepancies were resolved by a third reviewer. The primary outcome was HPV vaccine uptake.</p><p><strong>Results: </strong>Adolescents themselves were the most common foci of change. Barriers to rural HPV uptake included limited; vaccine awareness, access to vaccines for children vaccination sites, and primary care recommendations.</p><p><strong>Conclusions: </strong>Tailored interventions to rural parents/caregivers could increase uptake of the vaccine. Provider training increases HPV vaccine recommendations; programs should also be targeted to rural school nurses, pharmacists, and dental care providers. Linking primary care practices and public health dissemination strategies are key.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945006/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.3390/vaccines14020155
Yuhyun Ji, Kavitha Bekkari, Mohammed Shardar, Geoffrey A Walford, SamMoon Kim, Yaping Liu, Willis Read-Button, Kristina Tracy, Jennifer Kriss, Colleen Barr, Marissa Wolfle, Shailaa Kummar, Celia LaPorta, Rachel Graham, Lorenzo Chen, William James Smith, Kunal Bakshi, Nicholas Murgolo, Nicole Lea Sullivan
Background/Objectives: Adjuvants, added to vaccines to enhance immune responses, are central to shaping the magnitude and durability of immunity, yet their precise mechanisms remain incompletely defined. This study evaluated how diverse adjuvant combinations influence HPV vaccine immunogenicity in non-human primates, with a particular focus on impacts on hematopoietic biology-megakaryocytes and platelets-and broader innate and adaptive pathways. Methods: Eight adjuvanted formulations, each incorporating distinct immunomodulatory components and delivery platforms, were compared against an alum-only control in non-human primates. Longitudinal antibody titers (HPV16-specific) were measured up to 54 weeks, and blood transcriptomes were profiled at Day 1 and Day 7 after both prime and boost doses to assess pathway-level enrichment and gene-expression patterns. Results: Several adjuvant combinations significantly increased antibody titers at 54 weeks compared with alum alone. Formulations containing cationic lipid or monophosphoryl lipid A (MPL) were associated with enhanced antibody responses. Early upregulation of immune-related genes across innate and adaptive pathways was also observed, with some combinations (e.g., inclusion of QS21 or ISCOMs) showing similar trends. Distinct group- and time-dependent transcriptional signatures were observed, with higher-responding formulations exhibiting stronger enrichment in pathogen-influenced signaling and cellular/humoral immune programs. Conclusions: Adjuvant selection and formulation strategy substantially modulate vaccine immunogenicity and early transcriptional programs, including innate, adaptive, and hematopoietic pathways. While individual adjuvants differentially regulate immune and platelet-associated genes, common pathway-level patterns emerge across formulations. These findings suggest candidate mechanisms for prolonged vaccine efficacy and provide actionable insights to guide rational adjuvant design for sustained immune protection.
{"title":"Exploring the Impact of Adjuvants on Vaccine Immunity Through Hematopoietic Cells.","authors":"Yuhyun Ji, Kavitha Bekkari, Mohammed Shardar, Geoffrey A Walford, SamMoon Kim, Yaping Liu, Willis Read-Button, Kristina Tracy, Jennifer Kriss, Colleen Barr, Marissa Wolfle, Shailaa Kummar, Celia LaPorta, Rachel Graham, Lorenzo Chen, William James Smith, Kunal Bakshi, Nicholas Murgolo, Nicole Lea Sullivan","doi":"10.3390/vaccines14020155","DOIUrl":"10.3390/vaccines14020155","url":null,"abstract":"<p><p><b>Background/Objectives:</b> Adjuvants, added to vaccines to enhance immune responses, are central to shaping the magnitude and durability of immunity, yet their precise mechanisms remain incompletely defined. This study evaluated how diverse adjuvant combinations influence HPV vaccine immunogenicity in non-human primates, with a particular focus on impacts on hematopoietic biology-megakaryocytes and platelets-and broader innate and adaptive pathways. <b>Methods:</b> Eight adjuvanted formulations, each incorporating distinct immunomodulatory components and delivery platforms, were compared against an alum-only control in non-human primates. Longitudinal antibody titers (HPV16-specific) were measured up to 54 weeks, and blood transcriptomes were profiled at Day 1 and Day 7 after both prime and boost doses to assess pathway-level enrichment and gene-expression patterns. <b>Results:</b> Several adjuvant combinations significantly increased antibody titers at 54 weeks compared with alum alone. Formulations containing cationic lipid or monophosphoryl lipid A (MPL) were associated with enhanced antibody responses. Early upregulation of immune-related genes across innate and adaptive pathways was also observed, with some combinations (e.g., inclusion of QS21 or ISCOMs) showing similar trends. Distinct group- and time-dependent transcriptional signatures were observed, with higher-responding formulations exhibiting stronger enrichment in pathogen-influenced signaling and cellular/humoral immune programs. <b>Conclusions:</b> Adjuvant selection and formulation strategy substantially modulate vaccine immunogenicity and early transcriptional programs, including innate, adaptive, and hematopoietic pathways. While individual adjuvants differentially regulate immune and platelet-associated genes, common pathway-level patterns emerge across formulations. These findings suggest candidate mechanisms for prolonged vaccine efficacy and provide actionable insights to guide rational adjuvant design for sustained immune protection.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945058/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.3390/vaccines14020153
Vincenza Sansone, Gaia D'Antonio, Grazia Miraglia Del Giudice, Francesco Napolitano, Gabriella Di Giuseppe
Background/Objectives: Vaccination coverage among adolescents remains below the recommended target, highlighting the need for effective educational strategies to improve vaccine knowledge. This study aimed to assess baseline knowledge of vaccines and immune mechanisms among adolescents and to evaluate whether a school-based educational intervention can improve knowledge related to vaccination. Methods: A prospective quasi-experimental pre-post study was conducted between 1 February 2025 and 1 June 2025 among adolescents aged 14-19 years attending high schools in Southern Italy. The intervention was based on the e-Bug educational module and delivered by trained nurses through interactive lessons, gamification, and guided discussions. Vaccine-related knowledge was assessed using a questionnaire administered before and after the intervention. Changes in knowledge scores were analyzed using paired statistical tests, and the effect size was estimated. A stepwise multivariate linear regression model was employed to identify factors associated with post-intervention test scores, with statistical significance set as p ≤ 0.05. Results: Among 386 participants, the majority were female (74.2%), the average age was 15.8, and 15% reported a chronic medical condition. Knowledge gaps were observed at baseline, particularly regarding the items on recommended adolescent vaccinations (37.4%), the definition of innate immunity (25.6%), and the mechanism of vaccines' action (51%). After the intervention, all the items showed an improvement in correct answers, statistically significant for 5 of the 7 analyzed items (r = 0.364, p < 0.001). The most pronounced improvement was in the awareness of age-specific recommended vaccines (61.2%). The multivariate linear regression analysis showed that those with higher pre-intervention test scores, those who had parents with chronic medical conditions, those whose fathers worked, and those willing to participate in similar future interventions were more likely to achieve higher post-intervention test scores. Conclusions: School-based interventions may represent an effective strategy for enhancing adolescents' knowledge related to vaccination, but further studies with control groups and long-term follow-up are needed to confirm effectiveness.
背景/目的:青少年的疫苗接种覆盖率仍然低于建议的目标,突出表明需要制定有效的教育战略,以提高疫苗知识。本研究旨在评估青少年对疫苗和免疫机制的基本知识,并评估以学校为基础的教育干预是否可以提高与疫苗接种相关的知识。方法:在2025年2月1日至2025年6月1日期间,对意大利南部14-19岁的高中学生进行了一项前瞻性准实验前后研究。干预以e-Bug教育模块为基础,由训练有素的护士通过互动课程、游戏化和引导讨论进行。在干预前后使用问卷评估疫苗相关知识。运用配对统计检验分析知识得分的变化,并估计效应量。采用多元逐步线性回归模型识别干预后测试成绩的相关因素,p≤0.05为统计学显著性。结果:在386名参与者中,大多数是女性(74.2%),平均年龄为15.8岁,15%报告患有慢性疾病。在基线时观察到知识差距,特别是关于青少年推荐接种疫苗的项目(37.4%)、先天免疫的定义(25.6%)和疫苗作用机制(51%)。干预后,所有项目的正确答案均有改善,7个分析项目中有5个项目的正确答案有统计学意义(r = 0.364, p < 0.001)。最显著的改善是对年龄特异性推荐疫苗的认识(61.2%)。多元线性回归分析显示,干预前测试得分较高、父母有慢性疾病、父亲有工作以及未来愿意参加类似干预的孩子更有可能获得更高的干预后测试分数。结论:以学校为基础的干预措施可能是提高青少年疫苗接种相关知识的有效策略,但需要进一步的对照组研究和长期随访来证实有效性。
{"title":"Improving Vaccine Knowledge Among Adolescents: A Pre-Post School-Based Educational Intervention in Southern Italy.","authors":"Vincenza Sansone, Gaia D'Antonio, Grazia Miraglia Del Giudice, Francesco Napolitano, Gabriella Di Giuseppe","doi":"10.3390/vaccines14020153","DOIUrl":"10.3390/vaccines14020153","url":null,"abstract":"<p><p><b>Background/Objectives</b>: Vaccination coverage among adolescents remains below the recommended target, highlighting the need for effective educational strategies to improve vaccine knowledge. This study aimed to assess baseline knowledge of vaccines and immune mechanisms among adolescents and to evaluate whether a school-based educational intervention can improve knowledge related to vaccination. <b>Methods</b>: A prospective quasi-experimental pre-post study was conducted between 1 February 2025 and 1 June 2025 among adolescents aged 14-19 years attending high schools in Southern Italy. The intervention was based on the e-Bug educational module and delivered by trained nurses through interactive lessons, gamification, and guided discussions. Vaccine-related knowledge was assessed using a questionnaire administered before and after the intervention. Changes in knowledge scores were analyzed using paired statistical tests, and the effect size was estimated. A stepwise multivariate linear regression model was employed to identify factors associated with post-intervention test scores, with statistical significance set as <i>p</i> ≤ 0.05. <b>Results</b>: Among 386 participants, the majority were female (74.2%), the average age was 15.8, and 15% reported a chronic medical condition. Knowledge gaps were observed at baseline, particularly regarding the items on recommended adolescent vaccinations (37.4%), the definition of innate immunity (25.6%), and the mechanism of vaccines' action (51%). After the intervention, all the items showed an improvement in correct answers, statistically significant for 5 of the 7 analyzed items (r = 0.364, <i>p</i> < 0.001). The most pronounced improvement was in the awareness of age-specific recommended vaccines (61.2%). The multivariate linear regression analysis showed that those with higher pre-intervention test scores, those who had parents with chronic medical conditions, those whose fathers worked, and those willing to participate in similar future interventions were more likely to achieve higher post-intervention test scores. <b>Conclusions</b>: School-based interventions may represent an effective strategy for enhancing adolescents' knowledge related to vaccination, but further studies with control groups and long-term follow-up are needed to confirm effectiveness.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12944830/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147291135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.3390/vaccines14020152
Pablo Estrella-Porter, Amaya Sánchez-Gómez, María Dolores Lasheras Carbajo, Patricia Guillem Sáiz, Carmen Sáiz-Sánchez, Juan José Carreras
Background: Invasive meningococcal disease (IMD) caused by Neisseria meningitidis remains a major public health concern due to its severity, lethality, and long-term sequelae. To address the rise in serogroups W and Y in Spain, the Community of Madrid implemented a catch-up campaign in 2019-2021, targeting adolescents (ages 13-18) alongside routine tetravalent meningococcus vaccine (MenACWY) at age 12. This study evaluated MenACWY catch-up vaccination uptake in routine practice by describing vaccine coverage, temporal trends, and associated factors in adolescents born between 2001 and 2006. Methods: A population-based cross-sectional study was conducted using data from the Community of Madrid's vaccination registry (SISPAL Vacunas). Vaccination coverage was calculated for adolescents with at least one recorded MenACWY dose from age 10 onwards. Temporal trends were analyzed by birth cohort and calendar time, and multivariable logistic regression models were used to identify factors associated with vaccination uptake. Results: Among 424,059 adolescents, overall vaccination coverage by December 2021 was 63.8%, ranging from 54.4% to 78.2% across birth cohorts. Coverage was highest in the 2006 cohort, likely due to co-administration with the tetanus and diphtheria (Td) booster. A slightly higher uptake was observed among females and adolescents with chronic conditions, while foreign-born adolescents consistently showed lower coverage. COVID-19 disruptions led to temporal variability, with sharp declines during lockdowns and partial recoveries thereafter, with persistent sociodemographic differences in uptake. Conclusions: By December 2021, coverage was incomplete, with marked variability across birth cohorts. Higher uptake was observed when vaccination was integrated into routine visits, while persistent sociodemographic disparities remained evident. These observational findings are consistent with the programmatic value of combined catch-up and routine strategies and the need for targeted actions to ensure equitable MenACWY coverage.
{"title":"Evaluation of the MenACWY Vaccination Catch-Up Campaign Among Adolescents in Madrid: Coverage, Trends, and Determinants.","authors":"Pablo Estrella-Porter, Amaya Sánchez-Gómez, María Dolores Lasheras Carbajo, Patricia Guillem Sáiz, Carmen Sáiz-Sánchez, Juan José Carreras","doi":"10.3390/vaccines14020152","DOIUrl":"10.3390/vaccines14020152","url":null,"abstract":"<p><p><b>Background</b>: Invasive meningococcal disease (IMD) caused by <i>Neisseria meningitidis</i> remains a major public health concern due to its severity, lethality, and long-term sequelae. To address the rise in serogroups W and Y in Spain, the Community of Madrid implemented a catch-up campaign in 2019-2021, targeting adolescents (ages 13-18) alongside routine tetravalent meningococcus vaccine (MenACWY) at age 12. This study evaluated MenACWY catch-up vaccination uptake in routine practice by describing vaccine coverage, temporal trends, and associated factors in adolescents born between 2001 and 2006. <b>Methods</b>: A population-based cross-sectional study was conducted using data from the Community of Madrid's vaccination registry (SISPAL Vacunas). Vaccination coverage was calculated for adolescents with at least one recorded MenACWY dose from age 10 onwards. Temporal trends were analyzed by birth cohort and calendar time, and multivariable logistic regression models were used to identify factors associated with vaccination uptake. <b>Results</b>: Among 424,059 adolescents, overall vaccination coverage by December 2021 was 63.8%, ranging from 54.4% to 78.2% across birth cohorts. Coverage was highest in the 2006 cohort, likely due to co-administration with the tetanus and diphtheria (Td) booster. A slightly higher uptake was observed among females and adolescents with chronic conditions, while foreign-born adolescents consistently showed lower coverage. COVID-19 disruptions led to temporal variability, with sharp declines during lockdowns and partial recoveries thereafter, with persistent sociodemographic differences in uptake. <b>Conclusions</b>: By December 2021, coverage was incomplete, with marked variability across birth cohorts. Higher uptake was observed when vaccination was integrated into routine visits, while persistent sociodemographic disparities remained evident. These observational findings are consistent with the programmatic value of combined catch-up and routine strategies and the need for targeted actions to ensure equitable MenACWY coverage.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147291016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.3390/vaccines14020154
Laura E Sarabia, Elizabeth Williams, Kashmira Date, Estelle Méroc, Jennifer Eeuwijk, Bradford Gessner, Joseph Bresee, Alicia Fry, Elizabeth Begier
Respiratory infections cause substantial morbidity and mortality in older adults and other at-risk adult populations. Despite the availability of effective vaccines, adult vaccination coverage remains suboptimal. This narrative review examines strategies designed to improve vaccine uptake among non-pregnant adults aged ≥18 years and inform future adult vaccination strategies. We conducted a targeted literature search using keywords for vaccination, respiratory diseases, strategy/program/implementation, and adults in PubMed database and CDC, WHO, and ECDC websites, between 2014 and 2024. A snowball search of literature reviews and key references was also performed to identify additional relevant studies. Eligible publications focused on vaccination strategies against influenza, COVID-19, and pneumococcal disease targeting non-pregnant adults (≥18 years). We categorized the strategies by intervention type to describe their influence on vaccination campaigns and vaccine uptake/coverage. We included 45 publications, encompassing strategies focused on individual decision-making, healthcare system functions, and national policy. Educational and awareness interventions (such as healthcare worker/provider recommendations during consultation, phone calls, letters, text messages, and social media outreach) reportedly raised vaccination rates. Access-related factors, including convenient vaccination sites and free or subsidized vaccines, were reported to be important factors in improving coverage in underserved communities. Within healthcare settings, strategies such as continuous vaccine provider training and workflow/process optimization were shown to enhance vaccination delivery. At the local or national policy levels, legislation governing program targets shaped immunization efforts and facilitated collaborations and partnerships to expand campaign reach. The findings may inform policymakers and public health/immunization practitioners in designing context-specific immunization initiatives that effectively reach adult populations.
{"title":"Vaccination Strategies Against Respiratory Pathogens in the Adult Population: A Narrative Review.","authors":"Laura E Sarabia, Elizabeth Williams, Kashmira Date, Estelle Méroc, Jennifer Eeuwijk, Bradford Gessner, Joseph Bresee, Alicia Fry, Elizabeth Begier","doi":"10.3390/vaccines14020154","DOIUrl":"10.3390/vaccines14020154","url":null,"abstract":"<p><p>Respiratory infections cause substantial morbidity and mortality in older adults and other at-risk adult populations. Despite the availability of effective vaccines, adult vaccination coverage remains suboptimal. This narrative review examines strategies designed to improve vaccine uptake among non-pregnant adults aged ≥18 years and inform future adult vaccination strategies. We conducted a targeted literature search using keywords for vaccination, respiratory diseases, strategy/program/implementation, and adults in PubMed database and CDC, WHO, and ECDC websites, between 2014 and 2024. A snowball search of literature reviews and key references was also performed to identify additional relevant studies. Eligible publications focused on vaccination strategies against influenza, COVID-19, and pneumococcal disease targeting non-pregnant adults (≥18 years). We categorized the strategies by intervention type to describe their influence on vaccination campaigns and vaccine uptake/coverage. We included 45 publications, encompassing strategies focused on individual decision-making, healthcare system functions, and national policy. Educational and awareness interventions (such as healthcare worker/provider recommendations during consultation, phone calls, letters, text messages, and social media outreach) reportedly raised vaccination rates. Access-related factors, including convenient vaccination sites and free or subsidized vaccines, were reported to be important factors in improving coverage in underserved communities. Within healthcare settings, strategies such as continuous vaccine provider training and workflow/process optimization were shown to enhance vaccination delivery. At the local or national policy levels, legislation governing program targets shaped immunization efforts and facilitated collaborations and partnerships to expand campaign reach. The findings may inform policymakers and public health/immunization practitioners in designing context-specific immunization initiatives that effectively reach adult populations.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945287/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.3390/vaccines14020150
Christopher Hominski, Carolyn A Lin
Background/objectives: HPV vaccination rates among U.S. young adults remain unchanged at 47% since 2019. Barriers including misinformation, vaccine hesitancy, and stigma surrounding HPV's long-standing association with sexually transmitted infections have limited widespread acceptance among the male population. This experimental study explores how prevention messages incorporating an emotional flow element may influence vaccination intention. It also examines whether vaccination status may differentiate pre-exposure risk-taking tendencies and vaccine perceptions-as well as post-exposure HPV susceptibility, HPV severity, vaccine effectiveness, and emotional response-among young adults.
Methods: A one-factor between-subjects experiment (including facts-only vs. facts→threat vs. facts→threat→hope conditions) was conducted online with a group of Gen Z college students at a U.S. university (N = 440).
Results: ANCOVA results indicated that emotional flow embedded in the three message conditions did not result in significantly different emotional responses (across all participants) or vaccination intention among the unvaccinated participants. Whereas vaccinated participants reported greater perceived vaccine benefits, HPV susceptibility, HPV severity, and vaccine effectiveness, unvaccinated participants exhibited stronger emotional responses toward the facts→threat→hope message instead. Regression results revealed that vaccine perceptions, risk-taking tendencies, HPV susceptibility, and emotional response significantly predicted vaccination intention, in that order. TV advertising was identified as the leading HPV information source, followed by social media advertisements and recommendations from health professionals.
Conclusions: These findings highlight that incorporating emotional flow may enhance message engagement among unvaccinated individuals. HPV campaigns should consider increasing positive vaccine perceptions, alleviating perceived threat of HPV, and eliciting positive emotional response toward vaccination acceptance and adoption.
{"title":"Vaccine Perceptions Outweigh Emotional Flow in Predicting HPV Vaccination Intentions Among Gen Z College Students.","authors":"Christopher Hominski, Carolyn A Lin","doi":"10.3390/vaccines14020150","DOIUrl":"10.3390/vaccines14020150","url":null,"abstract":"<p><strong>Background/objectives: </strong>HPV vaccination rates among U.S. young adults remain unchanged at 47% since 2019. Barriers including misinformation, vaccine hesitancy, and stigma surrounding HPV's long-standing association with sexually transmitted infections have limited widespread acceptance among the male population. This experimental study explores how prevention messages incorporating an emotional flow element may influence vaccination intention. It also examines whether vaccination status may differentiate pre-exposure risk-taking tendencies and vaccine perceptions-as well as post-exposure HPV susceptibility, HPV severity, vaccine effectiveness, and emotional response-among young adults.</p><p><strong>Methods: </strong>A one-factor between-subjects experiment (including facts-only vs. facts→threat vs. facts→threat→hope conditions) was conducted online with a group of Gen Z college students at a U.S. university (<i>N</i> = 440).</p><p><strong>Results: </strong>ANCOVA results indicated that emotional flow embedded in the three message conditions did not result in significantly different emotional responses (across all participants) or vaccination intention among the unvaccinated participants. Whereas vaccinated participants reported greater perceived vaccine benefits, HPV susceptibility, HPV severity, and vaccine effectiveness, unvaccinated participants exhibited stronger emotional responses toward the facts→threat→hope message instead. Regression results revealed that vaccine perceptions, risk-taking tendencies, HPV susceptibility, and emotional response significantly predicted vaccination intention, in that order. TV advertising was identified as the leading HPV information source, followed by social media advertisements and recommendations from health professionals.</p><p><strong>Conclusions: </strong>These findings highlight that incorporating emotional flow may enhance message engagement among unvaccinated individuals. HPV campaigns should consider increasing positive vaccine perceptions, alleviating perceived threat of HPV, and eliciting positive emotional response toward vaccination acceptance and adoption.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12944949/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background/objectives: Porcine epidemic diarrhea virus (PEDV), particularly the emerging GII genotype, poses a severe threat to the swine industry in affected regions, primarily in Asia. Current vaccines based on classical strains often provide limited cross-protection against these heterogeneous variants, though it should be noted that these vaccines are primarily designed to induce maternal immunity in sows. The objective of this study was to develop a novel inactivated vaccine using an emerging PEDV GIIc variant and evaluate its immunogenicity and cross-protective efficacy against heterologous strains.
Methods: A novel PEDV strain, designated PEDV-HeN2024, was isolated from clinical samples and identified through cell culture, immunofluorescence assay (IFA), genetic sequencing, and phylogenetic analysis. An inactivated vaccine was prepared by emulsifying the purified virus with ISA 201 VG adjuvant (1:1, v/v). Immunogenicity was assessed in piglets by measuring virus-neutralizing antibody titers and PEDV-specific IgG levels. Cross-protective efficacy was evaluated through in vitro neutralization assays and in vivo challenge studies with homologous GIIc and heterologous GIIa and GIIb strains.
Results: The isolated PEDV-HeN2024 strain demonstrated pathogenicity, causing severe diarrhea and 100% mortality in PEDV-naïve neonatal piglets. Sera from vaccinated animals showed potent cross-neutralizing activity against homologous GIIc, as well as heterologous GIIa and GIIb strains. In challenge studies, vaccinated piglets were significantly protected against clinical disease, showing no diarrhea or viral shedding, and maintained normal intestinal architecture.
Conclusions: The inactivated vaccine developed from the emerging PEDV GIIc variant elicits robust humoral immunity and provides cross-protection against prevalent heterologous GII strains. These findings highlight its potential as a promising spectrum vaccine candidate for controlling PEDV outbreaks. This study underscores the importance of using recently circulating strains for vaccine development to overcome the limitations of current vaccines.
{"title":"A Novel Inactivated Vaccine Based on an Emerging PEDV GIIc Variant Provides Cross-Protection Against Heterologous GII Strains.","authors":"Jingjing Xu, Ningning Fu, Zimin Liu, Mengli Chen, Guijun Ma, Hehai Li, Jianghui Wang, Bo Yin, Zhen Zhang, Feifei Diao","doi":"10.3390/vaccines14020151","DOIUrl":"10.3390/vaccines14020151","url":null,"abstract":"<p><strong>Background/objectives: </strong>Porcine epidemic diarrhea virus (PEDV), particularly the emerging GII genotype, poses a severe threat to the swine industry in affected regions, primarily in Asia. Current vaccines based on classical strains often provide limited cross-protection against these heterogeneous variants, though it should be noted that these vaccines are primarily designed to induce maternal immunity in sows. The objective of this study was to develop a novel inactivated vaccine using an emerging PEDV GIIc variant and evaluate its immunogenicity and cross-protective efficacy against heterologous strains.</p><p><strong>Methods: </strong>A novel PEDV strain, designated PEDV-HeN2024, was isolated from clinical samples and identified through cell culture, immunofluorescence assay (IFA), genetic sequencing, and phylogenetic analysis. An inactivated vaccine was prepared by emulsifying the purified virus with ISA 201 VG adjuvant (1:1, <i>v</i>/<i>v</i>). Immunogenicity was assessed in piglets by measuring virus-neutralizing antibody titers and PEDV-specific IgG levels. Cross-protective efficacy was evaluated through in vitro neutralization assays and in vivo challenge studies with homologous GIIc and heterologous GIIa and GIIb strains.</p><p><strong>Results: </strong>The isolated PEDV-HeN2024 strain demonstrated pathogenicity, causing severe diarrhea and 100% mortality in PEDV-naïve neonatal piglets. Sera from vaccinated animals showed potent cross-neutralizing activity against homologous GIIc, as well as heterologous GIIa and GIIb strains. In challenge studies, vaccinated piglets were significantly protected against clinical disease, showing no diarrhea or viral shedding, and maintained normal intestinal architecture.</p><p><strong>Conclusions: </strong>The inactivated vaccine developed from the emerging PEDV GIIc variant elicits robust humoral immunity and provides cross-protection against prevalent heterologous GII strains. These findings highlight its potential as a promising spectrum vaccine candidate for controlling PEDV outbreaks. This study underscores the importance of using recently circulating strains for vaccine development to overcome the limitations of current vaccines.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945236/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147291006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-31DOI: 10.3390/vaccines14020148
Hasan Volkan Ege, Bilal Esat Temiz, Mihaela Grigore, Laura Burney Ellis, Sarah J Bowden, Belen Lopez-Cavanillas, Mario Preti, Ignacio Zapardiel, Elmar Joura, Murat Gültekin, Maria Kyrgiou
Background/Objectives: Persistent human papillomavirus (HPV) infection can lead to malignancies of the cervix, vulva, vagina, penis, anus, and oropharynx. The increasing incidence of HPV-related head and neck cancers has raised concerns regarding potential occupational exposure and transmission risks among healthcare workers. This study aimed to systematically evaluate the evidence on occupational HPV transmission in healthcare settings. Methods: A systematic review of the literature was conducted using three electronic databases (PubMed, Scopus, and Web of Science) from inception to August 2025, following PRISMA 2020 guidelines. A total of 34 studies met the inclusion criteria and were included in the review. Expert opinions and practical recommendations from members of the European Society of Gynaecological Oncology (ESGO) Prevention Committee were included to support interpretation of the results. Results: The available literature on occupational HPV transmission was limited, with a paucity of high-quality studies. Nevertheless, existing data suggest a potential occupational risk, particularly during aerosol or smoke-generating procedures performed for cervical intraepithelial neoplasia or cervical cancer. Several studies reported the detection of HPV DNA in surgical smoke or on instruments used during such procedures, indicating possible exposure among healthcare workers. Conclusions: Although current evidence is insufficient to definitively classify HPV infection as an occupational disease, available data indicate a potential exposure risk for healthcare workers involved in HPV-related procedures. Preventive measures, like personal protective equipment, should be emphasized. HPV vaccination has been recommended by some professional societies for healthcare workers performing gynecological procedures, though further research is needed to evaluate vaccine efficacy beyond the standard age range and its cost-effectiveness in this context.
背景/目的:持续的人乳头瘤病毒(HPV)感染可导致宫颈、外阴、阴道、阴茎、肛门和口咽部的恶性肿瘤。hpv相关的头颈癌发病率的增加引起了对卫生保健工作者潜在职业暴露和传播风险的关注。本研究旨在系统地评估卫生保健机构中职业HPV传播的证据。方法:根据PRISMA 2020指南,使用三个电子数据库(PubMed, Scopus和Web of Science)从成立到2025年8月对文献进行系统综述。共有34项研究符合纳入标准并被纳入本综述。来自欧洲妇科肿瘤学会(ESGO)预防委员会成员的专家意见和实际建议被包括在内,以支持对结果的解释。结果:关于职业HPV传播的现有文献有限,缺乏高质量的研究。然而,现有数据表明存在潜在的职业风险,特别是在对宫颈上皮内瘤变或宫颈癌进行气溶胶或产生烟雾的手术时。几项研究报告了在手术烟雾或手术过程中使用的仪器上检测到HPV DNA,表明卫生保健工作者可能接触到HPV。结论:虽然目前的证据不足以明确地将HPV感染归类为一种职业病,但现有数据表明,参与HPV相关程序的卫生保健工作者存在潜在的暴露风险。应强调个人防护装备等预防措施。一些专业协会建议从事妇科手术的卫生保健工作者接种HPV疫苗,但需要进一步研究来评估标准年龄范围以外的疫苗效力及其在这种情况下的成本效益。
{"title":"HPV Exposure in the Gynecological Practice: Time to Call It an Occupational Disease? A Systematic Review of the Literature and ESGO Experts' Opinion.","authors":"Hasan Volkan Ege, Bilal Esat Temiz, Mihaela Grigore, Laura Burney Ellis, Sarah J Bowden, Belen Lopez-Cavanillas, Mario Preti, Ignacio Zapardiel, Elmar Joura, Murat Gültekin, Maria Kyrgiou","doi":"10.3390/vaccines14020148","DOIUrl":"10.3390/vaccines14020148","url":null,"abstract":"<p><p><b>Background/Objectives:</b> Persistent human papillomavirus (HPV) infection can lead to malignancies of the cervix, vulva, vagina, penis, anus, and oropharynx. The increasing incidence of HPV-related head and neck cancers has raised concerns regarding potential occupational exposure and transmission risks among healthcare workers. This study aimed to systematically evaluate the evidence on occupational HPV transmission in healthcare settings. <b>Methods:</b> A systematic review of the literature was conducted using three electronic databases (PubMed, Scopus, and Web of Science) from inception to August 2025, following PRISMA 2020 guidelines. A total of 34 studies met the inclusion criteria and were included in the review. Expert opinions and practical recommendations from members of the European Society of Gynaecological Oncology (ESGO) Prevention Committee were included to support interpretation of the results. <b>Results:</b> The available literature on occupational HPV transmission was limited, with a paucity of high-quality studies. Nevertheless, existing data suggest a potential occupational risk, particularly during aerosol or smoke-generating procedures performed for cervical intraepithelial neoplasia or cervical cancer. Several studies reported the detection of HPV DNA in surgical smoke or on instruments used during such procedures, indicating possible exposure among healthcare workers. <b>Conclusions:</b> Although current evidence is insufficient to definitively classify HPV infection as an occupational disease, available data indicate a potential exposure risk for healthcare workers involved in HPV-related procedures. Preventive measures, like personal protective equipment, should be emphasized. HPV vaccination has been recommended by some professional societies for healthcare workers performing gynecological procedures, though further research is needed to evaluate vaccine efficacy beyond the standard age range and its cost-effectiveness in this context.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945036/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-31DOI: 10.3390/vaccines14020149
Yuyuan Zeng, Xihan Li, Yu Tian, Yuming Liu, Jianhong Wang, Qi An, Chuanyu Yang, Bo Zhou, Lili Zhang, Yangmu Huang, Lin Wang
Background: Children with special healthcare needs (CSHCNs) face persistent barriers to timely immunization in China, but comparative evidence across disease groups and vaccines, and data on immune function, are limited.
Methods: We conducted a retrospective cohort study linking electronic medical records, vaccination records, and a structured telephone and questionnaire follow-up. We estimated timely vaccination by National Immunization Program (NIP) dose definitions, assessed catch-up completion at follow-up, and compared cellular/humoral/complement immune indices with published pediatric reference ranges. Group differences used ANOVA/Kruskal-Wallis and chi-square (χ2)/Fisher's exact tests with Bonferroni correction.
Results: Timely vaccination was lower than the national healthy child benchmarks for all NIP vaccines (all p < 0.001); the Japanese encephalitis virus (JE; 24.0%) and measles-containing vaccine (MCV; 25.9%) had the lowest timely completion. A subset of CSHCNs did not receive recommended catch-up vaccinations, primarily due to persistent caregivers' concern and point of vaccination (POV) staff's hesitancy. Delays clustered in neonatal/perinatal disorders for Bacillus Calmette-Guérin (BCG) and hepatitis B vaccine, dose 1 (HepB1). Catch-up completion was highest for hepatitis B vaccine, dose 3 (HepB3) (86.3%) and BCG (81.8%), and lowest for the diphtheria and tetanus vaccine (DT) (49.4%); MCV2 completion was particularly low in hematological diseases. Immunoglobulin A (IgA) and immunoglobulin G (IgG) concentrations were significantly lower in neonatal/perinatal disorders and infectious disease groups versus neurological and immune disorder groups (p < 0.05). No severe adverse events were reported after catch-up.
Conclusions: CSHCNs in China face substantial barriers to timely NIP immunization. Timeliness and catch-up vary substantially by vaccine and underlying condition; neonatal/perinatal disorders contribute disproportionately to early-life delays. Disease-specific guidance, strengthened POV-specialist clinic coordination, immunological monitoring, and supportive policies could improve the vaccination coverage and effectiveness in this vulnerable population.
{"title":"Timeliness of Routine Vaccination, Catch-Up Completion, and Immune Function in Chinese Children with Special Healthcare Needs: A Retrospective Cohort Study.","authors":"Yuyuan Zeng, Xihan Li, Yu Tian, Yuming Liu, Jianhong Wang, Qi An, Chuanyu Yang, Bo Zhou, Lili Zhang, Yangmu Huang, Lin Wang","doi":"10.3390/vaccines14020149","DOIUrl":"10.3390/vaccines14020149","url":null,"abstract":"<p><strong>Background: </strong>Children with special healthcare needs (CSHCNs) face persistent barriers to timely immunization in China, but comparative evidence across disease groups and vaccines, and data on immune function, are limited.</p><p><strong>Methods: </strong>We conducted a retrospective cohort study linking electronic medical records, vaccination records, and a structured telephone and questionnaire follow-up. We estimated timely vaccination by National Immunization Program (NIP) dose definitions, assessed catch-up completion at follow-up, and compared cellular/humoral/complement immune indices with published pediatric reference ranges. Group differences used ANOVA/Kruskal-Wallis and chi-square (χ<sup>2</sup>)/Fisher's exact tests with Bonferroni correction.</p><p><strong>Results: </strong>Timely vaccination was lower than the national healthy child benchmarks for all NIP vaccines (all <i>p</i> < 0.001); the Japanese encephalitis virus (JE; 24.0%) and measles-containing vaccine (MCV; 25.9%) had the lowest timely completion. A subset of CSHCNs did not receive recommended catch-up vaccinations, primarily due to persistent caregivers' concern and point of vaccination (POV) staff's hesitancy. Delays clustered in neonatal/perinatal disorders for Bacillus Calmette-Guérin (BCG) and hepatitis B vaccine, dose 1 (HepB1). Catch-up completion was highest for hepatitis B vaccine, dose 3 (HepB3) (86.3%) and BCG (81.8%), and lowest for the diphtheria and tetanus vaccine (DT) (49.4%); MCV2 completion was particularly low in hematological diseases. Immunoglobulin A (IgA) and immunoglobulin G (IgG) concentrations were significantly lower in neonatal/perinatal disorders and infectious disease groups versus neurological and immune disorder groups (<i>p</i> < 0.05). No severe adverse events were reported after catch-up.</p><p><strong>Conclusions: </strong>CSHCNs in China face substantial barriers to timely NIP immunization. Timeliness and catch-up vary substantially by vaccine and underlying condition; neonatal/perinatal disorders contribute disproportionately to early-life delays. Disease-specific guidance, strengthened POV-specialist clinic coordination, immunological monitoring, and supportive policies could improve the vaccination coverage and effectiveness in this vulnerable population.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"14 2","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12945083/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}