Expert Review of Vaccines最新文献

{"title":"Interrupted time-series analysis of nationwide surveillance in Thai adult pneumococcal diseases over 14 years: evidence to inform policy in resource-limited countries.","authors":"Thundon Ngamprasertchai, Anusak Kerdsin, Narisa Ruenroengbun, Jintana Srisompong, Wutthiseth Dhitinanmuang, Rattagan Kajeekul, Kanokwan Laohasakprasit, Natthakit Chavapradit, Thanyarak Wongkamhla, Lantharita Charoenpong, Pinyo Rattanaumpawan, Saranath Lawpoolsri, Paul Turner","doi":"10.1080/14760584.2026.2645382","DOIUrl":"10.1080/14760584.2026.2645382","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to update the incidence and mortality of pneumococcal diseases and to evaluate the population-level trends in pneumococcal diseases incidence in Thailand, following PCV13 licensure and during the COVID-19 pandemic, in order to generate evidence supporting its inclusion in the National Immunization Program (NIP).</p><p><strong>Research design and methods: </strong>We conducted a quasi-experimental interrupted time-series analysis using sentinel hospital surveillance data from adults aged ≥ 18 years hospitalized with pneumococcal disease in Thailand between 2010 and 2024. Surveillance comprised retrospective passive data collection (2010-July 2023) and prospective active surveillance (August 2023-July 2024), applying consistent case definitions and outcome ascertainment methods throughout. Four epidemiologic periods were predefined based on PCV13 licensure and key phases of the COVID-19 pandemic.</p><p><strong>Results: </strong>Among 2069 hospitalized adults, 61.0% were aged ≥ 65 years. Non-invasive pneumococcal pneumonia (NIPP) accounted for 72.8% of cases, while invasive pneumococcal disease (IPD) comprised 27.2%, with a rising trend over time. The overall in-hospital fatality rate was 23.4%, significantly higher in IPD (31.7%) than in NIPP (20.4%, <i>p</i> < 0.001). The incidence of both IPD and NIPP nearly tripled over the study period. IPD increased from 1.43 to 4.05 per 100,000 population, while NIPP rose from 3.23 to 10.92 per 100,000 population, with a marked increase observed during the recent COVID-19 pandemic period. An increasing trend in macrolide resistance was observed in IPD and NIPP, particularly during the COVID-19 pandemic. Serotype analysis showed that PCV13 covered 79% of all isolates, PCV15 covered up to 79-81%, and PCV20 offered the broadest coverage (up to 95%), particularly for IPD.</p><p><strong>Conclusions: </strong>The burden of pneumococcal diseases in Thailand remains substantial, especially during the recent COVID-19 pandemic. The majority of disease-causing serotypes remained vaccine-type strains. Given that PCV13 or PCV15 inclusion in the Thai adult NIP should be prioritized to reduce the disease burden and antimicrobial-resistant pneumococcal infections.</p><p><strong>Clinical trial registration: </strong>This study was registered with the Thai Clinical Trial Registry (TCTR20230816007).</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2645382"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147431808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an adjuvanted, higher-dose, cell-based influenza vaccine: combining advanced technologies to improve vaccine effectiveness.","authors":"Mansoor Ashraf, Wendy Boivin, Jonathan S Nguyen-Van-Tam, Terry Nolan, Alicia N Stein, Colin A Russell","doi":"10.1080/14760584.2026.2667732","DOIUrl":"10.1080/14760584.2026.2667732","url":null,"abstract":"<p><strong>Introduction: </strong>Influenza remains a significant public health burden, particularly for high-risk populations such as older adults and those with chronic diseases. Effectiveness of standard-dose egg-grown influenza vaccines in these populations is variable and often adversely affected by antigenic drift and/or antigenic mismatch due to egg adaptation during manufacturing. In high-risk groups, vaccine effectiveness may be further reduced by immunosenescence and inflammation. Even modest improvements to seasonal influenza vaccine effectiveness could have a substantial public health benefit.</p><p><strong>Areas covered: </strong>Three key innovations already in widespread use have improved the effectiveness of influenza vaccines. First, vaccine adjuvants such as MF59 increase the magnitude, breadth, and duration of immune responses to both homologous and heterologous strains. Second, higher antigen doses boost immunogenicity and effectiveness. Third, propagation of vaccine strains in cell culture rather than embryonated hens' eggs avoids egg-adaptive mutations that can alter the antigenicity of the vaccine virus.</p><p><strong>Expert opinion: </strong>The individual benefits of each of these innovations inform the rationale for the development of a vaccine that combines them to further leverage their benefits: an adjuvanted, higher-dose, trivalent cell-based influenza vaccine (aTIVc). Early studies on aTIVc show that it elicits strong immune responses with an acceptable reactogenicity profile.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2667732"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the potential public health and economic impact and cost-effectiveness of vaccination strategies using an adapted COVID-19 vaccine in Guatemala.","authors":"Carlos Fernando Mendoza, Juan José Baldi-Castro, Moe H Kyaw, Iustina Chirila, Leo Alejandro Barrantes, Elena Aruffo, Ben Yarnoff, Karen Villamil-Herrera, Marcel Marcano-Lozada","doi":"10.1080/14760584.2026.2668675","DOIUrl":"10.1080/14760584.2026.2668675","url":null,"abstract":"<p><strong>Background: </strong>Using adapted COVID-19 vaccines targeting current variants in circulation is necessary for addressing the dynamic evolution of the SARS-CoV-2 virus.</p><p><strong>Research design and methods: </strong>Using a previously published combined Markov-decision tree model, this study estimated the outcomes of different vaccination strategies targeting various age and risk groups. The model used age-specific epidemiology, clinical, cost, and quality-of-life inputs derived from published literature and national surveillance data. Scenario analyses that included variations in COVID-19 incidence and sensitivity analyses that varied the parameters by ±20% were both conducted.</p><p><strong>Results: </strong>Compared to no vaccination, the vaccination of older adults aged ≥65 years and the high-risk population was estimated to prevent 12,933 symptomatic cases, 12,811 outpatient cases, 122 hospitalizations, 353 lost quality-adjusted life-years (QALYs) gained, and four deaths, translating to total direct and societal cost savings of US$9,424,605 and US$10,397,107 respectively. Expanding vaccination to adults aged ≥60 years and high-risk individuals further increased public health and economic benefits. Results were sensitive to assumptions regarding the underlying burden of infection, particularly underreporting.</p><p><strong>Conclusions: </strong>Implementing an adapted COVID-19 vaccine strategy for high-risk and older adults in Guatemala is projected to improve health outcomes and, under base-case assumptions, be cost-saving from both payer and societal perspectives.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":"25 1","pages":"2668675"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147940379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cost-effectiveness and public health impact of RSV immunization for all infants in Japan: a mixed strategy with nirsevimab and RSVpreF.","authors":"Naruhiko Ishiwada, Xinyu Wang, Takeshi Arashiro, Camille Reygrobellet, Benjamin Yarnoff, Robert Musci, Mehdi Ghemmouri","doi":"10.1080/14760584.2026.2694387","DOIUrl":"10.1080/14760584.2026.2694387","url":null,"abstract":"<p><strong>Background: </strong>Respiratory syncytial virus (RSV) remains a leading cause of medically attended lower respiratory tract disease (MA-LRTD) among infants in Japan. With the approval of maternal immunization (MI) and nirsevimab, Japan is transitioning from high-risk-targeted prophylaxis toward broader RSV prevention. This study evaluated the public health and economic impact of alternative MI and nirsevimab strategies within the Japanese National Immunization Program (NIP).</p><p><strong>Research designs and methods: </strong>A static decision-analytic cohort model estimated clinical and economic outcomes from birth through the first year of life (and the second RSV season for eligible high-risk infants). Strategies included an NIP-aligned scenario reflecting expected MI and nirsevimab, mixed nirsevimab-MI coverage scenarios, and nirsevimab-only. Outcomes included MA-LRTDs, hospitalizations, costs, quality-adjusted life-years (QALYs), and number needed to immunize (NNI) from payer and societal perspectives.</p><p><strong>Results: </strong>Compared with the NIP-aligned scenario, shifting coverage toward greater nirsevimab use reduced MA-LRTDs by 9.6% to 28.1%. A nirsevimab-only strategy reduced MA-LRTDs by 34.3% and hospitalizations by 33.4%. Under base-case assumptions, strategies with greater nirsevimab use improved outcomes and reduced costs, with lower NNI as coverage increased.</p><p><strong>Conclusions: </strong>For the Japanese setting, greater nirsevimab use improves outcomes and reduces costs, with nirsevimab-only strategies providing the greatest overall benefit.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2694387"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148301574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perceived implementation determinants of influenza vaccination by Chinese older adults: a CFIR-guided qualitative study comparing Beijing and Guizhou.","authors":"Yuxi Liu, Jiarui Zheng, Rujing Shi, Hao Jiang, Hairu Yu, Boer Qi, Yongming Jiang, Yanlin Cao, Mengmeng Jia, Luzhao Feng","doi":"10.1080/14760584.2026.2708193","DOIUrl":"10.1080/14760584.2026.2708193","url":null,"abstract":"<p><strong>Background: </strong>Influenza vaccination is an evidence-based intervention for older adults. However, vaccination coverage remains low and uneven in China, indicating persistent evidence-practice gap. Although older adults often express willingness to be vaccinated, uptake often varies across different implementation contexts. Therefore, we explored how implementation determinants govern vaccination uptake.</p><p><strong>Research design and methods: </strong>We conducted a comparative qualitative study using semi-structured interviews with older adults in Beijing and Guizhou. The interview guide was developed using the Consolidated Framework for Implementation Research (CFIR), and data were analyzed thematically and mapped to CFIR domains to compare determinants across sites.</p><p><strong>Results: </strong>Seventy-six participants were enrolled, including 40 from Beijing and 36 from Guizhou. Across both locations, many participants expressed willingness to be vaccinated but did not always follow through, reflecting an intention-uptake gap. Determinants in the Outer Setting and Process/Inner Setting domains were most significant in shaping vaccination uptake. Trusted communication and institutional triggers, including clinician recommendations and community reminders, facilitated vaccination uptake in Beijing. These cues were less available in Guizhou, where fragmented information contributed to delays and non-uptake.</p><p><strong>Conclusions: </strong>Implementation strategies should make influenza vaccination a more routine and system-supported component of healthy aging services. This requires stronger service delivery systems and standardized communication.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":"25 1","pages":"2708193"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148683941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Healthcare professionals' perspectives and preferences regarding adolescent meningococcal disease vaccination in the United States.","authors":"Oscar Herrera-Restrepo, Laurie Batchelder, Thatiana Pinto, Mickael Henry-Szatkowski, Dian Zhang, Adam Moore, Jennifer Bushen, Telisa Stewart, Jana Shaw","doi":"10.1080/14760584.2026.2696617","DOIUrl":"10.1080/14760584.2026.2696617","url":null,"abstract":"<p><strong>Background: </strong>Invasive meningococcal disease (IMD) is a vaccine-preventable, serious disease. In 2023-2024, the United States (US) Advisory Committee on Immunization Practices (ACIP) proposed revisions to the adolescent meningococcal vaccine schedule. This survey aimed to understand healthcare professionals' (HCPs') perspectives on these revisions and the potential role of the meningococcal serogroups A, B, C, W, Y (MenABCWY) vaccine.</p><p><strong>Methods: </strong>An online survey was conducted in May-June 2025 among US HCPs who regularly recommend meningococcal vaccines for 16-23-year-old patients. Responses were analyzed descriptively.</p><p><strong>Results: </strong>Of 302 HCPs, 73.2% felt the MenABCWY vaccine provides significant value to the meningococcal vaccination program, and almost half preferred a two-dose MenABCWY schedule over the ACIP recommendation, wherein a MenABCWY dose is followed by a MenB dose. Most HCPs indicated concern with removing MenACWY vaccination for 11-12-year-olds (84.8%). Comparatively, fewer were concerned about changing the MenB vaccine recommendation from shared clinical decision-making to risk-based (60.6%) and administering the second MenB dose closer to college entry (48.7%).</p><p><strong>Conclusions: </strong>While HCPs were receptive to revisions that simplify the vaccine schedule, this was not without concerns. The adolescent vaccination platform is essential to ensure continued protection against IMD; any changes will require clear, evidence-based guidance.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2696617"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148455093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adult respiratory syncytial virus infection and community-acquired pneumonia: pathogenesis, diagnostic challenges and the clinical implications.","authors":"Seong-Beom Park, Saeyong Lee, Sang-Kyu Shin, Jung Yeon Heo","doi":"10.1080/14760584.2026.2708194","DOIUrl":"10.1080/14760584.2026.2708194","url":null,"abstract":"<p><strong>Introduction: </strong>Community-acquired pneumonia (CAP) remains a significant cause of adult morbidity and mortality. Respiratory syncytial virus (RSV) contributes meaningfully to adult CAP, particularly in older adults and those with chronic cardiopulmonary disease, yet is frequently underdiagnosed because clinical features overlap with other respiratory infections and routine testing is limited.</p><p><strong>Areas covered: </strong>This review summarizes key virological and immunological characteristics of RSV, highlights diagnostic challenges in adults, and discusses clinical consequences beyond respiratory illness, including cardiovascular complications, severe in-hospital outcomes, and secondary bacterial infection with antibiotic exposure. Using Korean and international data, we emphasize the value of multi-specimen molecular testing to improve detection and discuss the implications for antimicrobial stewardship in CAP management. We also provide an overview of vaccine efficacy in phase 3 trials and early real-world effectiveness in older adults.</p><p><strong>Expert opinion: </strong>Reducing the adult RSV burden will require a feasible diagnostic pathway during periods of RSV circulation, strengthened surveillance that captures clinically meaningful outcomes, and targeted vaccination of high-risk populations. Ongoing post-authorization evaluation and research in immunocompromised and other high-risk groups are needed to optimize vaccination strategies and inform next-generation prevention.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":"25 1","pages":"2708194"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148583882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harnessing trained immunity for next-generation vaccines: from rational adjuvant design to self-adjuvanting antigens.","authors":"Jing Wang, Xiao-Yong Fan, Zhidong Hu","doi":"10.1080/14760584.2026.2721724","DOIUrl":"10.1080/14760584.2026.2721724","url":null,"abstract":"<p><strong>Introduction: </strong>The paradigm of trained immunity (TI), a <i>de facto</i> innate immune memory mediated by metabolic and epigenetic reprogramming of innate leukocytes, has expanded the conceptual framework for rational vaccine adjuvant design. Moving beyond conventional empiricism, TI offers a mechanistic basis that may enhance protection against certain heterologous pathogens, particularly in specific conditions.</p><p><strong>Areas covered: </strong>This review provides a comprehensive analysis of next-generation adjuvants engineered to induce TI. We outline the core mechanistic foundations encompassing the PI3K/Akt/mTOR/HIF1α-driven immunometabolic switch and ensuing chromatin rewiring, categorize emerging adjuvant strategies from natural TI inducers to synthetic pattern-recognition receptor agonists, direct metabolic-epigenetic modulators, and self-adjuvanting antigens, examine the enabling role of nanotechnology in achieving spatiotemporal control, and discuss translational roadmaps, safety considerations, and pivotal challenges.</p><p><strong>Expert opinion: </strong>TI-inducing adjuvants provide a mechanistic basis for bridging innate and adaptive immunity and represent a promising direction for next-generation vaccine development. Realizing their full potential will require resolving critical challenges in precision-tunability, host heterogeneity, and durability of the trained state, alongside defining validated correlates of protection. The convergence of systems immunology and advanced delivery platforms might accelerate the transition from concept to clinical vaccines, and contribute to the improved preparedness against infectious and noninfectious diseases.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":"25 1","pages":"2721724"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148789960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fc-mediated immune effector functions elicited by recombinant and live-attenuated herpes zoster vaccines.","authors":"Zhuangzhuang Huang, Pengfei Jin, Hongxing Pan, Mingwei Wei, Qi Liang, Mingzhi Gan, Simin Li, Xiangjun Zhai, Jingxin Li","doi":"10.1080/14760584.2026.2626919","DOIUrl":"10.1080/14760584.2026.2626919","url":null,"abstract":"<p><strong>Background: </strong>The role of Fc-mediated immune responses in protecting against herpes zoster remains poorly understood. This study aimed to evaluate the Fc-mediated immune responses of anti-VZV glycoprotein E antibodies induced by two licensed varicella-zoster virus vaccines.</p><p><strong>Research design and methods: </strong>We established two cohorts, each consisting of 48 healthy participants aged 50 or above, who received either the ZVL or RZV. Serum samples were measured to evaluate the Fc-mediated immune responses for antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and antibody-dependent neutrophil phagocytosis (ADNP) against VZV-gE. The correlations between Fc-mediated functions and the IgG levels were also analyzed.</p><p><strong>Results: </strong>Both ZVL and RZV significantly induced Fc effector function responses against HZ in participants after vaccination. Compared with ZVL recipients, RZV recipients exhibited significantly higher increase-fold of ADCC responses (ZVL: 1.93-fold; RZV: 8.44-fold, <i>p</i> < 0.001). In each vaccine group, the younger recipients showed higher ADCC responses than did the older (ZVL: 2.17-fold vs. 1.45-fold, <i>p</i> = 0.0136; RZV: 8.93-fold vs. 7.43-fold, <i>p</i> = 0.0677). Similar patterns were observed for ADCP and ADNP responses.</p><p><strong>Conclusion: </strong>RZV induced superior Fc effector functions of VZV-gE antibodies compared to ZVL did. Older adults exhibited weaker Fc-mediated responses compared to younger adults following vaccination.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2626919"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146112735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Approaches to observational study designs and analytical options to evaluate the safety of multi-dose vaccines: a systematic review.","authors":"Monica Mtei, Tu Pham Hien Trang, Adoración Navarro-Torné, Ian J Douglas, Anna Schultze","doi":"10.1080/14760584.2026.2667740","DOIUrl":"10.1080/14760584.2026.2667740","url":null,"abstract":"<p><strong>Introduction: </strong>Observational studies require careful considerations when evaluating the safety of multidose vaccines. We reviewed design and analytical approaches in observational studies evaluating the safety of multidose vaccines in the post-licensure phase.</p><p><strong>Methods: </strong>EMBASE, MEDLINE, Web of Science, and Scopus (2018-2022) were searched for hypothesis-testing studies evaluating the safety of multidose vaccines. Key features from frequently used designs were extracted.</p><p><strong>Results: </strong>Among 123 eligible studies, cohort (46%) and self-controlled case series (SCCS)/self-controlled risk interval (SCRI) (40%) followed by case-control (12%) were the most common designs, and 15% of studies used multiple designs. Among cohort studies evaluating multiple doses, vaccination date (36%) and cohort entry with time-updated exposure status (32%) were frequent approaches used to define time zero. Twenty-eight percent of cohort studies did not report time zero; all but one evaluated COVID-19 vaccine effect on post-delivery and fertility-related outcomes. For SCCS/SCRI, 64% of studies accounted for event-dependent exposures, mainly by including pre-exposure periods (53%) and modified SCCS model (48%), while 20% employed multiple correction strategies. Among studies using multiple designs, 68% reached consistent conclusions.</p><p><strong>Conclusions: </strong>SCCS/SCRI and cohort designs dominate multidose vaccine safety studies. Clear reporting on time zero in pregnancy and fertility-related cohort studies, and on addressing event-dependent exposures in SCCS/SCRI studies is needed, along with guidance on interpreting results from multiple designs.</p>","PeriodicalId":12326,"journal":{"name":"Expert Review of Vaccines","volume":" ","pages":"2667740"},"PeriodicalIF":5.6,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}