Vaccines

19 pages, 570 KB

Open AccessArticle

Understanding Vaccination Uptake Amongst Gay, Bisexual and Other Men Who Have Sex with Men in UK Sexual Health Services: A Qualitative Interview Study

by Tom May, Joanna M. Kesten, Hannah E. Family, Harriet Fisher, Adele Wolujewicz, Marta Checchi, Hamish Mohammed, David Leeman, Sema Mandal, Lucy Yardley, Jeremy Horwood and Clare Thomas

Vaccines 2026, 14(2), 112; https://doi.org/10.3390/vaccines14020112 (registering DOI) - 24 Jan 2026

Abstract

Background/Objectives: In England, gay, bisexual, and other men who have sex with men (GBMSM) are eligible for vaccination at NHS sexual health services, including human papillomavirus (HPV), hepatitis A virus (HAV), and hepatitis B virus (HBV) vaccines. However, current research shows limited [...] Read more.

Background/Objectives: In England, gay, bisexual, and other men who have sex with men (GBMSM) are eligible for vaccination at NHS sexual health services, including human papillomavirus (HPV), hepatitis A virus (HAV), and hepatitis B virus (HBV) vaccines. However, current research shows limited understanding of the factors influencing vaccination uptake among GBMSM. This study aimed to examine the barriers and facilitators affecting the offer and uptake of these vaccination programmes. Methods: A qualitative interview study following the Person-Based Approach (a systematic method for developing and optimising health interventions) involving GBMSM and sexual health service staff from two regions of England. Purposive sampling aimed to include GBMSM with diverse backgrounds and engagement with sexual health services. Patient and public involvement shaped the study design and interview topic guides. The interviews were recorded, transcribed, and thematically analysed to identify barriers and facilitators which were interpreted using the COM-B model of behaviour change. Results: Twenty GBMSM and eleven staff took part. The findings showed that opportunistic delivery of HPV, HAV, and HBV vaccination within sexual health services is mostly acceptable and feasible for GBMSM and staff, while also highlighting areas for optimization. Despite low knowledge of these viruses and their associated risks, willingness to be vaccinated was high, with healthcare provider recommendations and the convenience of vaccine delivery during routine clinic visits acting as important facilitators. However, the reach of opportunistic models was limited, particularly for individuals underserved by sexual health services or disengaged from GBMSM social networks. System-level barriers such as complex vaccine schedules (particularly when multiple schedules are combined), inconsistent access to vaccination histories, and limited system-level follow-up processes (e.g., automated invites and reminders) were also found to act as obstacles to vaccination uptake and delivery. Conclusions: To improve equitable uptake, sexual health services should explore the feasibility of addressing both individual and structural barriers through additional strategies, including targeted and persuasive communication to increase knowledge, leveraging regular contact with GBMSM to promote uptake, and implementing enhanced approaches to support vaccination completion (e.g., automated prompts or reminders). Full article

(This article belongs to the Special Issue Strategies to Enhance Vaccine Uptake and Immunization Among Underserved Populations/Vulnerable Groups)

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11 pages, 857 KB

Open AccessArticle

Factors Associated with the Anamnestic Immune Response Following Hepatitis B Booster Vaccination in the Elderly

by Chen Wang, Yan Zou, Xiaofei Wang and Na Liu

Vaccines 2026, 14(2), 111; https://doi.org/10.3390/vaccines14020111 - 23 Jan 2026

Abstract

Objective: To investigate factors influencing the anamnestic immune response 9 years after hepatitis B vaccination in elderly people (aged > 60 years). Methods: We quantitatively tested 630 elderly people who participated in the free hepatitis B vaccination program for adults in Zhangjiagang City [...] Read more.

Objective: To investigate factors influencing the anamnestic immune response 9 years after hepatitis B vaccination in elderly people (aged > 60 years). Methods: We quantitatively tested 630 elderly people who participated in the free hepatitis B vaccination program for adults in Zhangjiagang City during 2015 for hepatitis B surface antibody (anti-HBs) titers. Three booster doses of hepatitis B vaccine were given to subjects with anti-HBs titers below 10 mIU/mL, while a single booster dose was administered to those with titers between 10 and 100 mIU/mL, in accordance with their antibody titer measurements. The post-booster anti-HBs titers were evaluated at 2–3 months. A logistic regression model was used to identify factors influencing the anamnestic immune response, and a receiver operating characteristic curve analysis was conducted. Results: Among the 90 participants who received three doses and the 101 participants who received one dose, baseline characteristics did not differ significantly between the two cohorts. Both groups exhibited robust anamnestic immune responses. Significant differences were observed before and after booster vaccination within each group (Z = −8.24, p < 0.001; Z = −8.73, p < 0.001). Multivariate logistic regression indicated that individuals with higher pre-booster anti-HBs titers were less likely to show weak anamnestic responses compared to those with lower pre-booster titers (OR = 0.30, 95% CI: 0.16–0.58). Furthermore, a high anamnestic immune response (>1000 mIU/mL) was significantly more frequent among subjects with pre-booster titers ≥ 4.58 mIU/mL. Conclusions: Booster immunization administered nine years after hepatitis B vaccination induces robust anamnestic immunity, with its magnitude significantly correlated with pre-booster anti-HBs titers. Particular attention should be given to individuals with extremely low pre-booster anti-HBs levels. Full article

(This article belongs to the Special Issue Preventing Outbreak Through Vaccination)

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14 pages, 4488 KB

Open AccessArticle

From Bovine Immune Milk Profiling to Multi-Antigen Vaccine Design: Enhanced Humoral Responses Against H. pylori with a Flagellin and Urease Subunit Cocktail

by Hongru Li, Enhao Zhang, Jingyuan Ning, Yushan Lin, Guanyuan Wang, Hong Zhang, Cuixia Ma, Jiachao Wang, Miao Li, Xue Gao, Chenhui Li, Lin Wei, Xian Wang and Cuiqing Ma

Vaccines 2026, 14(2), 110; https://doi.org/10.3390/vaccines14020110 - 23 Jan 2026

Abstract

Objective: The aim of this study was to develop and evaluate non-antibiotic strategies against Helicobacter pylori by establishing a bovine immune milk platform and designing a synergistic multi-antigen immunogen to enhance humoral immune responses. Methods: Inactivated Helicobacter pylori (H. pylori) was used [...] Read more.

Objective: The aim of this study was to develop and evaluate non-antibiotic strategies against Helicobacter pylori by establishing a bovine immune milk platform and designing a synergistic multi-antigen immunogen to enhance humoral immune responses. Methods: Inactivated Helicobacter pylori (H. pylori) was used to immunize dairy cows, and the resulting immune milk was characterized for antibody specificity, acid stability, and target antigens via ELISA, Western blot, agglutination assays, and mass spectrometry. Key identified antigens (UreA, UreB, UreE, UreG, HypA, FlaA, and FlaB) were produced as recombinant proteins. Their immunogenicity was evaluated in a murine model, comparing single antigens with various protein combinations. Immune responses were assessed by antigen-specific IgG ELISA, bacterial agglutination titers, flow cytometry for T-cell activation, and histopathology for safety. Results: Immune milk contained high-titer, acid-stable IgG antibodies targeting multiple H. pylori virulence factors. In mice, while single proteins induced specific IgG, a multi-antigen cocktail (FlaA + FlaB + HypA + UreA + UreB + UreE + UreG) elicited significantly higher serum agglutination titers (~7 × 10³) than single antigens or inactivated whole-cell vaccine, alongside robust CD4⁺ T-cell activation. No formulations showed any hepatorenal or splenic toxicity. Conclusion: Bovine immune milk is a viable platform for acid-stable antibody delivery. A rationally designed multi-antigen cocktail synergistically enhances functional humoral immunity in vivo, providing a promising foundation for developing antibody-based or subunit vaccine strategies against H. pylori. Full article

(This article belongs to the Special Issue Novel Vaccine Designs to Enhance the Engagement of Innate and Adaptive Immunity)

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13 pages, 2870 KB

Open AccessArticle

A Chemically Induced Vibrio harveyi Bacterial Ghost Vaccine Confers Enhanced Protection in Turbot (Scophthalmus maximus)

by Haixiang Lv, Jianye Yang, Ruofan Yu, Qin Liu and Xiaohong Liu

Vaccines 2026, 14(1), 109; https://doi.org/10.3390/vaccines14010109 - 22 Jan 2026

Abstract

Background: Vibrio harveyi is a major bacterial pathogen threatening turbot aquaculture, necessitating the development of more effective vaccines. Bacterial ghosts (BGs), which are empty bacterial envelopes with preserved surface antigens, offer a promising alternative to traditional formaldehyde-killed vaccines that often suffer from reduced [...] Read more.

Background: Vibrio harveyi is a major bacterial pathogen threatening turbot aquaculture, necessitating the development of more effective vaccines. Bacterial ghosts (BGs), which are empty bacterial envelopes with preserved surface antigens, offer a promising alternative to traditional formaldehyde-killed vaccines that often suffer from reduced immunogenicity. Methods: We developed an optimized BGs vaccine for V. harveyi by combining the nonionic surfactant NP-40 with sodium hydroxide (NaOH). This NP-40/NaOH combination demonstrated a synergistic lytic effect, halving the minimum inhibitory concentration of NaOH required for complete inactivation. Results: The resulting BGs exhibited intact cellular morphology with transmembrane pores, efficient removal of cytoplasmic contents, and significantly better preservation of lipopolysaccharide structure compared to NaOH-alone treatment. Vaccination trials in turbot demonstrated that the NP-40/NaOH BGs provided the highest relative percent survival (RPS = 58.8%) upon challenge, outperforming both NaOH-alone BGs (RPS = 55.0%) and a traditional formaldehyde-killed vaccine (RPS = 34.8%). The superior protection was correlated with the induction of a more robust and sustained immune response, characterized by significantly higher levels of specific IgM antibodies, elevated lysozyme activity, and increased total serum protein. Conclusions: This study establishes the NP-40/NaOH protocol as an effective strategy for producing high-quality BGs with enhanced immunogenicity, presenting a potent vaccine candidate for controlling vibriosis in aquaculture. Full article

(This article belongs to the Special Issue Advances in Aquatic Animal Immunology and Vaccine Development for Disease Prevention)

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11 pages, 884 KB

Open AccessReview

Shifting Perspective in Influenza Vaccines Efficacy: How Risk Difference Shows an Alternative View of the Comparative Efficacy Profile of Newer and Enhanced Influenza Vaccines Compared to Standard, Egg-Based Vaccines

by Laura Colombo, Abraham Palache and Sanjay Hadigal

Vaccines 2026, 14(1), 108; https://doi.org/10.3390/vaccines14010108 - 22 Jan 2026

Abstract

Annual influenza vaccination remains critical for mitigating severe illness and reducing healthcare strain, particularly among high-risk populations. Despite advancements in vaccine platforms, the comparative efficacy of novel vaccines—such as high-dose (HD-IIV), recombinant (rIV), cell-based (cIV), and adjuvanted (aIV) influenza vaccines—versus standard-dose non-adjuvanted (SD-IIV) [...] Read more.

Annual influenza vaccination remains critical for mitigating severe illness and reducing healthcare strain, particularly among high-risk populations. Despite advancements in vaccine platforms, the comparative efficacy of novel vaccines—such as high-dose (HD-IIV), recombinant (rIV), cell-based (cIV), and adjuvanted (aIV) influenza vaccines—versus standard-dose non-adjuvanted (SD-IIV) vaccines remains a public health concern. Traditional Relative Vaccine Efficacy (rVE) metrics, though robust, may overestimate population-level benefits. This short communication explores alternative comparative efficacy measures: risk difference (ΔRD) and number needed to vaccinate (ΔNNV). Analysis of data derived from randomized controlled trials (RCTs), or robust pragmatic trials, shows that while rVE values for newer vaccines often indicate superior efficacy, ΔRD and ΔNNV highlight the limits in incremental protection at the population level, with ΔRD generally below 10 cases per 1000 vaccinated. These findings underline the sustained relevance of SD-IIV in immunization programs and emphasize the need for broader vaccine coverage to highlight the benefits of vaccination and enhance population health outcomes. Full article

(This article belongs to the Special Issue The Recent Development of Influenza Vaccine: 2nd Edition)

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15 pages, 1255 KB

Open AccessArticle

Development of an mRNA Vaccine for Tick-Borne Encephalitis: Selection of a Prototype Virus Strain

by Maria A. Nikiforova, Vladimir A. Gushchin, Denis A. Kleymenov, Anastasia M. Kocherzhenko, Evgeniia N. Bykonia, Elena P. Mazunina, Sofia R. Kozlova, Leonid I. Russu, Nadezhda A. Kuznetsova, Elena V. Shidlovskaya, Elizaveta V. Marchuk, Evgeny V. Usachev, Olga V. Usacheva, Dmitry V. Shcheblyakov, Irina V. Kozlova, Sergei E. Tkachev, Andrei A. Pochtovyi, Vladimir I. Zlobin, Denis Y. Logunov and Alexander L. Gintsburg

Vaccines 2026, 14(1), 107; https://doi.org/10.3390/vaccines14010107 - 21 Jan 2026

Abstract

Background/Objectives: While tick-borne encephalitis virus (TBEV) is genetically relatively conserved, the significant antigenic divergence between its main circulating subtypes hinders the development of broadly effective antiviral treatments and vaccines. Current inactivated TBEV vaccines offer limited cross-protection against heterologous strains, as evidenced by [...] Read more.

Background/Objectives: While tick-borne encephalitis virus (TBEV) is genetically relatively conserved, the significant antigenic divergence between its main circulating subtypes hinders the development of broadly effective antiviral treatments and vaccines. Current inactivated TBEV vaccines offer limited cross-protection against heterologous strains, as evidenced by cases among vaccinated individuals in endemic regions. The aim of this study was to design a candidate mRNA vaccine and evaluate the breadth of protective immunity it elicits. Methods: Ten candidate mRNA-PrM/E-LNP vaccines were comparatively evaluated for immunogenicity and protective efficacy in BALB/c mice. Immunogenicity was assessed by measuring antigen-specific IgG titers via ELISA and neutralizing antibody titers against a panel of TBEV strains using a virus-neutralization test. Protective efficiency was determined in a lethal challenge model, where immunized mice were challenged with one of seven distinct TBEV strains. Results: Vaccination with all tested mRNA-PrM/E-LNP candidates conferred 100% survival in mice following a lethal challenge with each of the seven TBEV strains (100 LD₅₀). The construct mRNA-PrM/E—Krasny Yar-8 demonstrated the highest immunogenicity, inducing antigen-specific antibodies with a geometric mean titer (GMT) of 1:6625, as well as the broadest virus-neutralizing activity against both homologous and heterologous TBEV strains in vitro. Conclusions: The mRNA platform represents a promising strategy for developing TBEV vaccines, demonstrating high immunogenicity and cross-protective efficacy against diverse viral strains. Full article

(This article belongs to the Special Issue Feature Papers of DNA and mRNA Vaccines)

15 pages, 2088 KB

Open AccessArticle

Preparation and Efficacy Evaluation of Heat-Resistant Freeze-Dried Live-Attenuated Vaccine Formulation of Micropterus salmoides Rhabdovirus

by Hongru Liang, Guangwei Hu, Xia Luo, Qiang Lin, Xiaozhe Fu, Yinjie Niu, Baofu Ma, Wenwen Xiao, Zhengwei Cui and Ningqiu Li

Vaccines 2026, 14(1), 106; https://doi.org/10.3390/vaccines14010106 - 21 Jan 2026

Abstract

Background/Objectives: An attenuated strain of Micropterus salmoides rhabdovirus (MSRV) 0509 with good immunogenicity has been isolated, showing potential as a candidate for live vaccine development. Methods: To improve the shelf life of attenuated strain of MSRV0509, the virus was formulated using three distinct [...] Read more.

Background/Objectives: An attenuated strain of Micropterus salmoides rhabdovirus (MSRV) 0509 with good immunogenicity has been isolated, showing potential as a candidate for live vaccine development. Methods: To improve the shelf life of attenuated strain of MSRV0509, the virus was formulated using three distinct single-protectant formulations and twelve thermostable protective agent formulations (designated T1–T12). Following lyophilization, the thermostability of each formulation was evaluated. Results: Results indicated that formulations T1, T9, and T10 maintained stable viral titers after storage at 25 °C and 37 °C. Moreover, these formulations retained high viral viability after 12 months at 4 °C, with a titer reduction of less than 0.5 log₁₀. Immunological analyses revealed that the freeze-dried MSRV vaccine elicited both humoral and immune factors responses in largemouth bass. Immersion immunization provided effective protection, yielding a survival rate exceeding 80%. Freeze-dried vaccines maintained their immunogenicity (i.e., the ability to induce antibodies) following 12 months of storage at 4 °C. Additionally, expression of IFN-γ and IL-12 was significantly upregulated in fish post-vaccination. Conclusions: In conclusion, the lyophilized MSRV vaccine developed in this study not only exhibits improved thermostability and extended shelf life, but also effectively preserves its immunogenic properties, supporting its potential for practical aquaculture applications. Full article

(This article belongs to the Section Veterinary Vaccines)

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20 pages, 1305 KB

Open AccessReview

Vaccination Against Respiratory Infections in Adults with Cancer: A Concise Guide for Clinicians

by Kay Choong See

Vaccines 2026, 14(1), 105; https://doi.org/10.3390/vaccines14010105 - 21 Jan 2026

Abstract

Global cancer incidence reached 20 million new cases across 185 countries in 2022, with approximately 10 million cancer-related deaths annually. Among adults with solid tumors and hematological malignancies, infections are a major contributor to morbidity and mortality, with respiratory infections playing a particularly [...] Read more.

Global cancer incidence reached 20 million new cases across 185 countries in 2022, with approximately 10 million cancer-related deaths annually. Among adults with solid tumors and hematological malignancies, infections are a major contributor to morbidity and mortality, with respiratory infections playing a particularly significant role. These infections not only reduce life expectancy but can also delay cancer therapy, negatively affect treatment outcomes, and increase healthcare costs. In recent years, the burden of respiratory infections in this population has been driven by influenza virus, SARS-CoV-2, respiratory syncytial virus, Streptococcus pneumoniae, and Bordetella pertussis. Effective vaccines are available for all these pathogens and are recommended for adults with cancer, yet vaccination uptake remains suboptimal despite their heightened vulnerability. This review provides practical guidance for healthcare professionals on vaccinating adults with cancer against respiratory infections, summarizing key information to help clinicians address vaccination-related complacency, confidence, and convenience. Evidence from studies in both the general population and cancer patients consistently shows that vaccination benefits outweigh potential risks, with adverse event rates comparable to those seen in individuals without cancer. Early vaccination is encouraged, as there is limited justification for delaying immunization even when immune responses may be reduced. Vaccine dosing aligns with recommendations for the general population, with important exceptions. Live attenuated vaccines should be avoided because of the risk of replication and disease in immunocompromised patients, and selected groups may require booster doses to achieve adequate protection. Notably, cancer immunotherapy does not appear to impair vaccine-induced immune responses. Full article

(This article belongs to the Special Issue Challenges to Developing New Vaccines and Improving Existing Platforms)

29 pages, 1055 KB

Open AccessReview

Hidden Targets in Cancer Immunotherapy: The Potential of “Dark Matter” Neoantigens

by Francois Xavier Rwandamuriye, Alec J. Redwood, Jenette Creaney and Bruce W. S. Robinson

Vaccines 2026, 14(1), 104; https://doi.org/10.3390/vaccines14010104 - 21 Jan 2026

Abstract

The development of cancer immunotherapies has transformed cancer treatment paradigms, yet durable and tumour-specific responses remain elusive for many patients. Neoantigens, immunogenic peptides arising from tumour-specific genomic alterations, have emerged as promising cancer vaccine targets. Early-phase clinical trials using different vaccine platforms, including [...] Read more.

The development of cancer immunotherapies has transformed cancer treatment paradigms, yet durable and tumour-specific responses remain elusive for many patients. Neoantigens, immunogenic peptides arising from tumour-specific genomic alterations, have emerged as promising cancer vaccine targets. Early-phase clinical trials using different vaccine platforms, including mRNA, peptide, DNA, and viral vector-based personalised cancer vaccines, have demonstrated the feasibility of targeting neoantigens, with early signals of prolonged survival in some patients. Most current vaccine strategies focus on canonical neoantigens, typically derived from exonic single-nucleotide variants (SNVs) and small insertions/deletions (INDELs), yet this represents only a fraction of the potential neoantigen repertoire. Evidence now shows that non-canonical neoantigens, arising mostly from alternative splicing, intron retention, translation of non-coding RNAs, gene fusions, and retroelement activation, broaden the antigenic landscape, with the potential for increasing tumour specificity and immunogenicity. In this review, we explore the biology of non-canonical neoantigens, the technological advances that now enable their systematic detection, and their potential to inform next-generation personalised cancer vaccines. Full article

(This article belongs to the Special Issue Tumor Vaccines: Current Processes, Prevailing Challenges and Future Perspectives)

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17 pages, 4217 KB

Open AccessArticle

Elicitation of Protective Immune Responses Against Influenza Virus Following Intranasal Delivery of Fluzone or Flublok Vaccines

by Naoko Uno, Matthew H. Thomas, Camila Caetano and Ted M. Ross

Vaccines 2026, 14(1), 103; https://doi.org/10.3390/vaccines14010103 - 21 Jan 2026

Abstract

Background/Objectives: While new vaccines are in development; one strategy to increase influenza vaccine coverage is to repurpose current influenza vaccines for intranasal delivery. Methods: To address this goal; mice were vaccinated intranasally with either a split inactivated virus vaccine (Fluzone) or a recombinant [...] Read more.

Background/Objectives: While new vaccines are in development; one strategy to increase influenza vaccine coverage is to repurpose current influenza vaccines for intranasal delivery. Methods: To address this goal; mice were vaccinated intranasally with either a split inactivated virus vaccine (Fluzone) or a recombinant HA vaccine (Flublok) at one of two doses (1 μg high dose or 0.1 μg low dose). Both vaccines were adjuvanted with either a STING agonist; c-di-AMP (CDA); or a combination of a synthetic toll-like receptor (TLR) 4 and TLR7/8 agonist (TRAC478). Results: Mice vaccinated with either vaccine plus adjuvant had higher hemagglutination-inhibition titers than mice administered unadjuvanted vaccines. Mice vaccinated with either vaccine plus CDA had on average higher numbers of H3 and influenza B hemagglutinin (HA)-specific antibody-secreting cells (ASCs); whereas mice vaccinated with vaccine plus TRAC478 had on average higher number of H1 HA-specific ASCs. All vaccinated mice challenged with the H1N1 influenza virus were protected against both morbidity and mortality with no detectable virus in their lungs. Mice challenged with the H3N2 influenza virus all lost weight over the first 5 days of infection. Adding TRAC478 with either a high or low dose vaccine resulted in 80–100% survival following challenge. Almost all mice vaccinated with Flublok plus CDA died from H3N2 influenza virus challenged with ~2 logs higher viral lung titers than mice administered Flublok only or Flublok plus TRAC478. Conclusions: Overall; Fluzone and Flublok can effectively be used for intranasal vaccination. Full article

(This article belongs to the Special Issue Immunity to Influenza Viruses and Vaccines)

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12 pages, 651 KB

Open AccessArticle

Real-World Effectiveness of Seasonal Influenza Vaccines During the 2024–2025 Season: Subgroup Analyses by Virus Subtype, Time Since Vaccination, and Diagnostic Method

by Yu Jung Choi, Jungmin Lee, Joon Young Song, Seong-Heon Wie, Jacob Lee, Jin-Soo Lee, Hye Won Jeong, Joong Sik Eom, Jang Wook Sohn, Young Kyung Yoon, Won Suk Choi, Eliel Nham, Jin Gu Yoon, Ji Yun Noh, Man-Seong Park and Hee Jin Cheong

Vaccines 2026, 14(1), 102; https://doi.org/10.3390/vaccines14010102 - 21 Jan 2026

Abstract

Background/Objectives: Despite high vaccination coverage, influenza remains a public health concern in South Korea, particularly in older adults. Continuous evaluation of vaccine effectiveness (VE) is essential to optimize immunization strategies. Methods: This study evaluated seasonal influenza VE for preventing laboratory-confirmed influenza [...] Read more.

Background/Objectives: Despite high vaccination coverage, influenza remains a public health concern in South Korea, particularly in older adults. Continuous evaluation of vaccine effectiveness (VE) is essential to optimize immunization strategies. Methods: This study evaluated seasonal influenza VE for preventing laboratory-confirmed influenza using a test-negative design through a hospital-based influenza surveillance system in South Korea from 1 November 2024, to 30 April 2025. Demographic and clinical information was collected through questionnaire surveys and electronic medical records. Influenza was diagnosed using rapid antigen tests (RATs) and reverse transcription polymerase chain reaction (RT-qPCR), and vaccine effectiveness was analyzed using multivariable logistic regression. Results: In total, 3954 participants were included, with 1977 influenza-positive cases and 1977 test-negative controls. Influenza A and B accounted for 93.1% and 7.0% of cases, respectively. The adjusted overall VE was 20.4% (95% confidence interval [CI], 8.2–30.9; p = 0.002). VE was higher in adults aged 50–64 years (46.8%) than in those aged ≥65 years (18.8%). VE was 19.9% against influenza A and 45.7% against A/H3N2. VE was higher among individuals tested using RT-qPCR than among those tested using RATs (21.5% vs. 15.7%), and was also greater during the early period than during the late period (20.5% vs. 11.4%). Vaccination did not reduce influenza-associated hospitalization risk (VE, 17.3%; 95% CI, −9.3 to 37.4). A significant reduction in hospitalization risk was observed in adults aged 50–64 years (VE, 46.8%), with no significant benefit in those aged ≥65 years. Conclusions: The 2024–2025 seasonal influenza vaccine provided moderate protection against laboratory-confirmed influenza in adults, with higher effectiveness in those aged 50–64 years. Full article

(This article belongs to the Section Influenza Virus Vaccines)

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18 pages, 854 KB

Open AccessArticle

HPV and HIV Among Youth: Exploring the Role of Knowledge, Risk Perception, and Attitude to Vaccination in Prevention Strategies

by Silvia Cocchio, Andrea Cozza, Matilde Obici, Elisabetta Conte, Claudia Cozzolino Cangiano, Nicoletta Parise, Patrizia Furlan and Vincenzo Baldo

Vaccines 2026, 14(1), 101; https://doi.org/10.3390/vaccines14010101 - 21 Jan 2026

Abstract

Background: Sexually transmitted infections (STIs) represent a significant public health problem due to their impact. Knowledge about them, perceptions of the risk of contracting them, and adherence to prevention strategies such as HPV vaccination are, at various levels, key factors in preventing [...] Read more.

Background: Sexually transmitted infections (STIs) represent a significant public health problem due to their impact. Knowledge about them, perceptions of the risk of contracting them, and adherence to prevention strategies such as HPV vaccination are, at various levels, key factors in preventing the spread of STIs. The study therefore aimed to investigate and evaluate, in a group of young Italians, the level of knowledge, perception of risk and propensity to adhere to preventive strategies, including vaccination against papillomavirus. Methods: A cross-sectional study was conducted by administering a questionnaire to young people aged between 16 and 30, residing in four macro-geographical areas, collecting socio-demographic, behavioral and knowledge data. Levels of knowledge about STIs and HPV were classified into four categories (low, medium without awareness, medium with awareness, high). Risk perception was assessed on a scale of 1 to 10. Results: A total of 2576 questionnaires were collected, revealing that general knowledge about STIs is limited: only 12.5% of participants demonstrated a high level of knowledge, while 27.1% demonstrated a low level; with regard to HPV, 41.3% of the sample demonstrated a low level of knowledge. The perception of the risk of contracting HIV and HPV was low in most subjects (average score of approximately 2.9 out of 10), with no significant differences related to levels of knowledge about HPV. Potential adherence to HPV vaccination was high (83.0% considered vaccination useful), but among unvaccinated subjects, almost half expressed concerns about vaccination, related to poor knowledge and mistrust of vaccines in general. Factors associated with a higher frequency of self-reported STIs included older age, transgender identity, non-heterosexual orientation, and risky sexual behavior. Conclusions: The results emerging from the study highlight the urgent need to strengthen educational and preventive interventions aimed at young people. Raising awareness of the risk of contracting STIs and the importance of vaccination are key targets for health promotion interventions. Full article

(This article belongs to the Section Vaccines and Public Health)

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12 pages, 745 KB

Open AccessArticle

Epidemiological Characteristics of Mumps Under Different Immunization Strategies in Henan Province

by Zhanpei Xiao, Mingxia Lu, Yating Ma, Yan Wang, Mingyu Zhang, Binghui Du, Yiran Bai, Yuzhu Ma and Yanyang Zhang

Vaccines 2026, 14(1), 100; https://doi.org/10.3390/vaccines14010100 - 20 Jan 2026

Abstract

Background: On 1 January 2019, a 2-dose mumps-containing vaccine (MuCV) immunization strategy was adopted in Henan Province before the national Expanded Program on Immunization (EPI). This study examines the epidemiological characteristics of mumps cases during the implementation of various immunization strategies in Henan [...] Read more.

Background: On 1 January 2019, a 2-dose mumps-containing vaccine (MuCV) immunization strategy was adopted in Henan Province before the national Expanded Program on Immunization (EPI). This study examines the epidemiological characteristics of mumps cases during the implementation of various immunization strategies in Henan Province. Methods: We employed descriptive statistics and initially retrieved data on reported cases from 2004 to 2024. Mumps case data were sourced from the China Information System for Disease Control and Prevention (CISDCP). Results: Between 2004 and 2024, a total of 301,342 cases of mumps disease were reported in Henan Province, and the average annual reported incidence was 15.11 cases per 100,000 people. The average yearly incidence decreased by 60.29% following the implementation of the 2-dose vaccination strategy compared with the one-dose strategy. The study identifies two annual incidence peaks from 2004 to 2024: a prominent peak from April to July and a smaller peak from December to January. From 2019 to 2024, in addition to a slight dip in February, the seasonality was less pronounced, with cases distributed sporadically throughout the year. The proportion of the population over 20 years old increased annually, from 8.17% in 2004–2008 to 15.55% in 2019–2024. There was an overall negative correlation between the estimated MuCV vaccination rate and the reported incidence of mumps (r = −0.685, p < 0.05). Conclusions: The introduction of 2-dose MuCV in the EPI significantly reduced the incidence rate and total number of cases. While continuing the 2-dose MuCV immunization strategy in the future, it is crucial to remain vigilant in preventing and controlling mumps among individuals over 20 years old. Full article

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3 pages, 133 KB

Open AccessEditorial

Closing Editorial—Special Issue on Veterinary Vaccines and Host Immune Responses

by Ayumi Matsuyama-Kato and Mohamed Faizal Abdul-Careem

Vaccines 2026, 14(1), 99; https://doi.org/10.3390/vaccines14010099 - 20 Jan 2026

Abstract

As this Special Issue concludes, we are delighted to highlight the diversity, depth, and translational potential of the assembled contributions [...] Full article

(This article belongs to the Special Issue Veterinary Vaccines and Host Immune Responses)

11 pages, 1442 KB

Open AccessArticle

The Role of MASP1, MASP2, and Mannose-Binding Lectin in the Immune Response to Hepatitis B Vaccination in Infants

by Ayşe Esra Tapcı, İsmail Bulut, Serçin Taşar, Zeynep Kallimci, Kezban Çavdar Yetkin, Meliha Sevim, Oğuzhan Serin, Medine Ayşin Taşar, Mehmet Şenes and Bülent Alioğlu

Vaccines 2026, 14(1), 98; https://doi.org/10.3390/vaccines14010098 - 20 Jan 2026

Abstract

Background: Hepatitis B vaccination is the most effective strategy for preventing chronic hepatitis B virus (HBV) infection; however, interindividual variability in vaccine-induced antibody responses remains a significant challenge in the field. Innate immune components, particularly lectin complement pathway proteins such as mannose-binding lectin [...] Read more.

Background: Hepatitis B vaccination is the most effective strategy for preventing chronic hepatitis B virus (HBV) infection; however, interindividual variability in vaccine-induced antibody responses remains a significant challenge in the field. Innate immune components, particularly lectin complement pathway proteins such as mannose-binding lectin (MBL), mannose-associated serine protease 1 (MASP-1), and mannose-associated serine protease 2 (MASP-2), may contribute to this variability in outcomes. This study aimed to evaluate the association between serum MBL, MASP-1, and MASP-2 levels, birth weight, and humoral response to hepatitis B vaccination in infants. Methods: This single-center prospective observational study included 37 term infants who received hepatitis B vaccinations at birth, 1 month, and 6 months of age according to the national immunization schedule. Venous blood samples were collected at month 6, before, and month 7 after the 3rd vaccine dose. Serum MBL, MASP-1, MASP-2, and antiHB levels were measured using commercial ELISA and chemiluminescence assays. Data were analyzed using non-parametric statistical tests and Spearman’s correlation analysis. Results: AntiHB levels increased significantly following vaccination (median Pre-3rdVac: 125.8 mIU/mL; Post-3rdVac: 609.7 mIU/mL; p < 0.001). MASP-1 concentrations also showed a significant Post-3rdVac increase (median Pre-3rdVac: 809.52 ng/mL; Post-3rdVac: 1133.93 ng/mL; p = 0.019). Birth weight was positively correlated with both MASP-1 levels (r_s = 0.492, p = 0.004) and changes in MASP-1 concentrations (r_s = 0.524, p = 0.002) after the third dose. In addition, MASP-1 levels were positively associated with antiHB levels (r_s = 0.385, p = 0.030) and Post-3rdVac antiHB titers (r_s = 0.493, p = 0.004). In contrast, serum MBL and MASP-2 concentrations were not significantly associated with antiHB levels before or after vaccination. Conclusions: MASP-1, but not MBL or MASP-2, is associated with the magnitude of the antibody response to hepatitis B vaccination in infants. These findings suggest that specific components of the lectin pathway may influence vaccine-induced immunity, independent of MBL. Further large-scale studies incorporating genetic and functional analyses are warranted to clarify the mechanisms by which lectin pathway proteins shape hepatitis B vaccine response. Full article

(This article belongs to the Special Issue Pediatric Vaccinations)

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25 pages, 3895 KB

Open AccessArticle

Evaluation of a Respiratory Syncytial Virus Subunit Vaccine Candidate in IgA-Deficient Mice: Insights into the Role of IgA in Vaccine-Induced Immunity and Protection

by Liliana Gonzalez Gonzalez, Mina Zhiani, Jourdan Witt and Sylvia van Drunen Littel-van den Hurk

Vaccines 2026, 14(1), 97; https://doi.org/10.3390/vaccines14010097 - 20 Jan 2026

Abstract

Background/Objectives: Respiratory Syncytial Virus (RSV) causes severe disease in infants, the elderly, and immunocompromised individuals, with reinfections linked to poor induction of durable mucosal immunoglobulin A (IgA). We investigated the role of IgA in immunity and protection induced by a RSV subunit vaccine [...] Read more.

Background/Objectives: Respiratory Syncytial Virus (RSV) causes severe disease in infants, the elderly, and immunocompromised individuals, with reinfections linked to poor induction of durable mucosal immunoglobulin A (IgA). We investigated the role of IgA in immunity and protection induced by a RSV subunit vaccine candidate, tFrsc/TriAdj, which consists of a truncated RSV fusion protein (tFrsc) with a tri-component adjuvant (TriAdj). Methods: Wild-type (IgA⁺/⁺) and IgA-deficient (IgA⁻/⁻) BALB/c mice were immunized intranasally and subsequently challenged with RSV. Results: Vaccination with tFrsc/TriAdj induced robust systemic and mucosal IgG, and high lung and serum neutralizing antibodies, in both IgA⁺/⁺ and IgA⁻/⁻ mice. As expected, IgA⁻/⁻ mice lacked IgA and exhibited modest reductions in nasal IgG compared to IgA^+/+ mice following challenge, correlating to failure to clear RSV from the upper respiratory tract. In contrast, viral replication in the lungs was fully suppressed in both genotypes, indicating that IgG alone was sufficient for lower respiratory tract protection. Isotype analysis revealed diminished Th1-associated IgG2a and elevated IgG1 across mucosal and systemic compartments in IgA⁻/⁻ mice, suggesting a Th2 bias. Flow cytometric analysis confirmed reduced recruitment of IFN-γ⁺ CD4⁺ T cells in the lungs of immunized IgA⁻/⁻ mice. Interestingly, IL-17 production and numbers of IL-17⁺ CD4⁺ T cells in the lungs were increased, suggesting an enhanced Th17 response. Furthermore, IgA-deficient mice displayed reduced splenic IgG⁺ B cell populations, which is also a novel observation. Conclusions: Collectively, these findings demonstrate that although tFrsc/TriAdj confers lower airway protection in the absence of IgA, vaccine-induced IgA is critical for upper airway protection, Th1/balanced immune responses, and optimal B cell responses. Full article

(This article belongs to the Section Vaccine Design, Development, and Delivery)

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16 pages, 460 KB

Open AccessArticle

Trusted Sources of COVID-19 Vaccine Information by County Characteristics in North Carolina

by Bryson T. Staley, Michael E. DeWitt, Jennifer J. Wenner, John W. Sanders, Thomas F. Wierzba and Katherine Poehling

Vaccines 2026, 14(1), 96; https://doi.org/10.3390/vaccines14010096 (registering DOI) - 20 Jan 2026

Abstract

Background/Objectives: The COVID-19 pandemic disproportionately impacted rural areas across the United States, including rural North Carolina (NC). Consistent with national patterns, COVID-19 vaccination coverage as of December 2022 was higher for non-rural (72%) than rural (58%) NC counties. The role of trusted sources [...] Read more.

Background/Objectives: The COVID-19 pandemic disproportionately impacted rural areas across the United States, including rural North Carolina (NC). Consistent with national patterns, COVID-19 vaccination coverage as of December 2022 was higher for non-rural (72%) than rural (58%) NC counties. The role of trusted sources of vaccine information used by rural and non-rural residents is unknown. Methods: Using data from two surveys distributed by the COVID-19 Community Research Partnership from 8 June 2021 through 21 December 2021, we compared self-reported sources of trusted COVID-19 vaccine information by non-rural and rural counties and by county-level predominant political vote in the 2020 Presidential election. Results: While NC respondents were highly vaccinated (94%), fewer residents from rural counties self-reported COVID-19 vaccination than those from non-rural counties (91% versus 95%). The most common reported source of trusted vaccine information was federal health agencies. The proportion citing a federal health agency was higher for respondents from non-rural (80%) than rural (72%) counties and was higher for vaccinated (75%) than unvaccinated (42%) rural respondents. The next two most trusted sources of vaccine information were state/local health officials (48%) and health care providers (42%). Among trusted resources reported by 10–15% of respondents, those from rural counties were less likely to use hospital websites, employers, or news sources than those from non-rural counties. More respondents from counties with >60% vote for the 2020 Democratic Presidential candidate cited federal health agencies, state and local officials, and new sources than respondents from counties with >60% vote for the 2020 Republican Presidential candidate. Conclusions: By identifying the trusted sources of vaccine information for residents in non-rural and rural NC counties, future vaccine implementation efforts can tailor communication efforts to increase vaccine uptake and potentially reduce the rates of hospitalizations and death from vaccine-preventable diseases such as COVID-19 or other future pandemics. Full article

(This article belongs to the Special Issue Vaccine Hesitancy in the Era of COVID-19)

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1 pages, 115 KB

Open AccessCorrection

Correction: Wang et al. Immune Persistence Following a Single Dose of Varicella Vaccine: 5-Year and 8-Year Follow-Up of a Phase 3, Randomized, Double-Blind, Placebo-Controlled Trial. Vaccines 2025, 13, 1024

by Yanxia Wang, Xiangling Lei, Lili Huang, Yuehong Ma, Hongxue Yuan, Dongyang Zhao and Fanhong Meng

Vaccines 2026, 14(1), 95; https://doi.org/10.3390/vaccines14010095 - 20 Jan 2026

Abstract

There was an error in the original publication [...] Full article

17 pages, 5297 KB

Open AccessArticle

Liver Safety Assessment of an Indonesian Hexavalent Vaccine Candidate Through Histopathology and ALT/AST Evaluation in Rats and Rabbits

by Elisa D. Pratiwi, Tiza W. Mawaddah, Arif R. Sadjuri, Dimas T. Nugroho, Arip Hidayat, Astria N. Nidom, Zakiyyan I. Ayyuba, Eka S. Wahyuningsih, Kuncoro P. Santoso, Hani Plumeriastuti, Soeharsono, Setyarina Indrasari, Reviany V. Nidom, Acep R. Wijayadikusumah and Chairul A. Nidom

Vaccines 2026, 14(1), 94; https://doi.org/10.3390/vaccines14010094 - 19 Jan 2026

Abstract

Background: Administering several separate childhood vaccines can reduce adherence to immunization schedules due to missed appointments and the burden of repeated injections. A hexavalent formulation targeting diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type B, and poliovirus offers a practical approach to improve [...] Read more.

Background: Administering several separate childhood vaccines can reduce adherence to immunization schedules due to missed appointments and the burden of repeated injections. A hexavalent formulation targeting diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type B, and poliovirus offers a practical approach to improve compliance and streamline immunization. Methods: Toxicity testing was performed in Wistar rats and New Zealand White rabbits (60 rats and 30 rabbits). Animals were distributed into three groups: hexavalent vaccine + low-dose sIPV, hexavalent vaccine + high-dose sIPV, and control. Each animal received a 0.5 mL intramuscular injection at weeks 0, 4, 8, and 12. Clinical observations were conducted throughout the study. Serum samples were collected one day before each injection and at the endpoint, while liver tissue was collected at the endpoint. ALT and AST concentrations were analyzed using an automated analyzer, and hepatic morphology was evaluated microscopically. Results: No abnormal clinical signs related to vaccination were observed. ALT concentrations showed no significant differences (p > 0.05). AST differences (p < 0.05) were detected between the high-dose group and the control on day 27 in female rabbits and on day 83 in female rats; however, all values remained within normal physiological limits. Histopathological examination revealed no irreversible hepatic lesions, including hydropic degeneration, portal inflammation, focal necrosis, or connective tissue proliferation, and no significant differences were noted (p > 0.05). Conclusions: Repeated administration of the hexavalent vaccine candidate at low and high doses produced no toxicological effects in animal models, supporting its safety for further clinical development. Full article

(This article belongs to the Section Vaccine Advancement, Efficacy and Safety)

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