Pub Date : 2025-10-01Epub Date: 2025-08-21DOI: 10.1016/j.jvacx.2025.100710
Caitriona Murphy , Mike Y.W. Kwan , Eunice L.Y. Chan , Joshua S.C. Wong , Sheena G. Sullivan , Malik Peiris , Benjamin J. Cowling , So-Lun Lee
Influenza began circulating in Hong Kong in mid-December 2024. As of 12 March 2025, 1279 children were enrolled in a prospective test negative study for influenza vaccine effectiveness (VE). Among 209 influenza-positive cases, 71 % had influenza A(H1N1), 11 % had influenza A(H3N2), 3 % had influenza A with unknown subtype, and 15 % had influenza B. Among the test-negative controls, 53 % had received influenza vaccination since August 2024. End of the winter season VE estimates against hospitalization associated with influenza A(H1N1) was 64.8 % (95 % CI: 38.1 % to 80.3 %) and for influenza A(H3N2) was 59.9 % (95 % CI: −42.0 % to 89.6 %). These findings indicate that influenza vaccination provided protection against hospitalization for influenza A(H1N1) and A(H3N2) in children, highlighting the importance of continued vaccination efforts in Hong Kong.
{"title":"Influenza vaccine effectiveness against hospitalizations associated with influenza a in Hong Kong children aged 9 months to 17 years, 2024/25","authors":"Caitriona Murphy , Mike Y.W. Kwan , Eunice L.Y. Chan , Joshua S.C. Wong , Sheena G. Sullivan , Malik Peiris , Benjamin J. Cowling , So-Lun Lee","doi":"10.1016/j.jvacx.2025.100710","DOIUrl":"10.1016/j.jvacx.2025.100710","url":null,"abstract":"<div><div>Influenza began circulating in Hong Kong in mid-December 2024. As of 12 March 2025, 1279 children were enrolled in a prospective test negative study for influenza vaccine effectiveness (VE). Among 209 influenza<strong>-</strong>positive cases, 71 % had influenza A(H1N1), 11 % had influenza A(H3N2), 3 % had influenza A with unknown subtype, and 15 % had influenza B. Among the test-negative controls, 53 % had received influenza vaccination since August 2024. End of the winter season VE estimates against hospitalization associated with influenza A(H1N1) was 64.8 % (95 % CI: 38.1 % to 80.3 %) and for influenza A(H3N2) was 59.9 % (95 % CI: −42.0 % to 89.6 %). These findings indicate that influenza vaccination provided protection against hospitalization for influenza A(H1N1) and A(H3N2) in children, highlighting the importance of continued vaccination efforts in Hong Kong.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100710"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have previously reported reasons for vaccine hesitance among those who did not receive the coronavirus disease 2019 (COVID-19) vaccination. However, the detailed causes of hesitancy related to booster vaccinations remain largely uninvestigated. This study aimed to describe why individuals who received one or two vaccine doses avoided booster shots.
Methods
In March 2023, a cross-sectional Internet survey was conducted to investigate the reasons for vaccine hesitancy and the extent of adverse reactions following vaccination among individuals who had not received a booster dose in Japan. Survey items included social demographics, comorbidities, history of SARS-CoV-2 infection, history of COVID-19 vaccination, adverse reactions to COVID-19 vaccines, and reasons for vaccination decline. The reasons for avoiding vaccination were summarized.
Results
In this study, 545 individuals were included: 262 did not receive vaccination, 21 received one dose, and 263 received two doses by March 2023. The most common reason for avoiding subsequent booster doses among individuals who received one or two doses of the vaccine was concerns about adverse reactions (n[%] = 192 [67.8 %]), followed by concerns about vaccine safety (n[%] = 154 [54.4 %]). The proportion of vaccine safety concerns was lower in the booster vaccination hesitant group than in the non-vaccination group (p < 0.001). The group that avoided booster vaccination due to adverse reactions experienced all types of adverse reactions more severely than those for which adverse reactions were not a reason for vaccine hesitancy.
Conclusions
The most prominent reason for avoiding booster doses after receiving one or two doses of the COVID-19 vaccine was related to concerns regarding associated side effects. To prevent vaccine hesitancy regarding booster doses, including COVID-19, the strategy for reducing discomfort caused by these adverse reactions should involve the first and second doses.
{"title":"Reasons for unvaccinated booster dose of COVID-19, adverse reaction after vaccination, and COVID-19 infection status among those with COVID-19 booster vaccination hesitancy","authors":"Sho Takahashi , Shohei Sakai , Yuichiro Ohki , Kaede Tobe , Yurie Kobashi , Masaharu Tsubokura","doi":"10.1016/j.jvacx.2025.100701","DOIUrl":"10.1016/j.jvacx.2025.100701","url":null,"abstract":"<div><h3>Background</h3><div>We have previously reported reasons for vaccine hesitance among those who did not receive the coronavirus disease 2019 (COVID-19) vaccination. However, the detailed causes of hesitancy related to booster vaccinations remain largely uninvestigated. This study aimed to describe why individuals who received one or two vaccine doses avoided booster shots.</div></div><div><h3>Methods</h3><div>In March 2023, a cross-sectional Internet survey was conducted to investigate the reasons for vaccine hesitancy and the extent of adverse reactions following vaccination among individuals who had not received a booster dose in Japan. Survey items included social demographics, comorbidities, history of SARS-CoV-2 infection, history of COVID-19 vaccination, adverse reactions to COVID-19 vaccines, and reasons for vaccination decline. The reasons for avoiding vaccination were summarized.</div></div><div><h3>Results</h3><div>In this study, 545 individuals were included: 262 did not receive vaccination, 21 received one dose, and 263 received two doses by March 2023. The most common reason for avoiding subsequent booster doses among individuals who received one or two doses of the vaccine was concerns about adverse reactions (n[%] = 192 [67.8 %]), followed by concerns about vaccine safety (n[%] = 154 [54.4 %]). The proportion of vaccine safety concerns was lower in the booster vaccination hesitant group than in the non-vaccination group (<em>p</em> < 0.001). The group that avoided booster vaccination due to adverse reactions experienced all types of adverse reactions more severely than those for which adverse reactions were not a reason for vaccine hesitancy.</div></div><div><h3>Conclusions</h3><div>The most prominent reason for avoiding booster doses after receiving one or two doses of the COVID-19 vaccine was related to concerns regarding associated side effects. To prevent vaccine hesitancy regarding booster doses, including COVID-19, the strategy for reducing discomfort caused by these adverse reactions should involve the first and second doses.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100701"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-09-03DOI: 10.1016/j.jvacx.2025.100714
Hoang Dinh Phi , Tran Ngoc Ca , Pham Mai Oanh , Nguyen Thien Phong , Ong Thinh , Pham Thi Hong Nhung
The measles vaccine has a profound impact, significantly reducing incidence and morbidity. However, challenges in achieving high vaccination coverage have resulted in substantial burdens on child health and financial hardship for households. This study evaluates the protective effects of measles vaccination against severity and mortality in Northern Vietnam from 2017 to 2019 and related economics of vaccination.
We conducted a retrospective analysis of all laboratory-confirmed measles cases admitted to Vietnam National Children Hospital (VNCH), estimating odds ratios between vaccinated and unvaccinated groups while considering disease severity, mortality, and potential confounders. We also analyzed cost - benefit using data from two sources, including VNCH data and National Infectious Disease Surveillance System.
Among 2064 inpatients, vaccinated children exhibited fewer pneumonia complications and shorter hospitalization duration. Vaccination significantly reduced the risk of severity and mortality with an adjusted OR = 0.46 (0.28–0.72). Treatment costs were significantly lower in the vaccinated group compared to the unvaccinated group. Cost – benefit analysis show that vaccination can save for 4.98 USD to 26.20 USD per measle case with prior vaccination.
Vaccination significantly reduces severe disease risk, pneumonia complications, and treatment costs. Expanding vaccination coverage (including children, young mothers and women of childbearing age) and targeted financial support in high-risk areas are essential for improving health outcomes and alleviating economic burdens on families.
{"title":"Impact of measles vaccination on disease severity and economic burden among children in northern Vietnam, 2017–2019","authors":"Hoang Dinh Phi , Tran Ngoc Ca , Pham Mai Oanh , Nguyen Thien Phong , Ong Thinh , Pham Thi Hong Nhung","doi":"10.1016/j.jvacx.2025.100714","DOIUrl":"10.1016/j.jvacx.2025.100714","url":null,"abstract":"<div><div>The measles vaccine has a profound impact, significantly reducing incidence and morbidity. However, challenges in achieving high vaccination coverage have resulted in substantial burdens on child health and financial hardship for households. This study evaluates the protective effects of measles vaccination against severity and mortality in Northern Vietnam from 2017 to 2019 and related economics of vaccination.</div><div>We conducted a retrospective analysis of all laboratory-confirmed measles cases admitted to Vietnam National Children Hospital (VNCH), estimating odds ratios between vaccinated and unvaccinated groups while considering disease severity, mortality, and potential confounders. We also analyzed cost - benefit using data from two sources, including VNCH data and National Infectious Disease Surveillance System.</div><div>Among 2064 inpatients, vaccinated children exhibited fewer pneumonia complications and shorter hospitalization duration. Vaccination significantly reduced the risk of severity and mortality with an adjusted OR = 0.46 (0.28–0.72). Treatment costs were significantly lower in the vaccinated group compared to the unvaccinated group. Cost – benefit analysis show that vaccination can save for 4.98 USD to 26.20 USD per measle case with prior vaccination.</div><div>Vaccination significantly reduces severe disease risk, pneumonia complications, and treatment costs. Expanding vaccination coverage (including children, young mothers and women of childbearing age) and targeted financial support in high-risk areas are essential for improving health outcomes and alleviating economic burdens on families<strong>.</strong></div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100714"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-23DOI: 10.1016/j.jvacx.2025.100709
Brenda Aline Maya Badillo , Diana Laura Hernández García , Rodrigo Armando Moreno García , Guillermo Orta Pineda , Carlos Javier Alcázar Ramiro , Juana Castillo Castillo , Mario Solís Hernández , Roberto Navarro López , Armando García López
Since 2021, the activity and impact of the highly pathogenic H5N1 avian influenza virus have intensified worldwide, causing high mortality in wild birds and birds while also infecting various wild and domestic mammals and humans. Particularly, the severe impact on commercial poultry farming has prompted various countries to implement control and mitigation plans to address the damage caused by these viruses. In Mexico, the implementation of vaccination was part of the comprehensive strategies to prevent and control highly pathogenic H5N1 avian influenza outbreaks. For this reason, this work aimed to compare antibody levels in production birds before and after vaccination, examining seroconversion and seroprotection after vaccination in two time periods. Serum samples were taken before and after vaccination in 573 Poultry Production Units during the first vaccination period and 205 Poultry Production Units during the second period across various Mexican states. These samples, later, underwent hemagglutination inhibition tests. With the results obtained from serology, comparisons of medians, calculations of seroconversion and seroprotection, as well as logistic regression analysis were performed. As expected, vaccination led to a statistically higher immune response in birds in most of Mexico's states. However, seroconversion and seroprotection rates remained below 80 % during the first evaluation period. Progenitors and commercial posture birds showed better immune responses to vaccination, particularly with vaccines developed through reverse genetics. These results provide valuable insights into the immune response of Mexican domestic birds under the national strategic plan to control the highly pathogenic influenza A H5N1 virus emergency, which will set a precedent to improve the prevention and control of future outbreaks.
{"title":"H5N1 highly pathogenic avian influenza vaccination: Seroresponse of mexican poultry in the 2022–2024","authors":"Brenda Aline Maya Badillo , Diana Laura Hernández García , Rodrigo Armando Moreno García , Guillermo Orta Pineda , Carlos Javier Alcázar Ramiro , Juana Castillo Castillo , Mario Solís Hernández , Roberto Navarro López , Armando García López","doi":"10.1016/j.jvacx.2025.100709","DOIUrl":"10.1016/j.jvacx.2025.100709","url":null,"abstract":"<div><div>Since 2021, the activity and impact of the highly pathogenic H5N1 avian influenza virus have intensified worldwide, causing high mortality in wild birds and birds while also infecting various wild and domestic mammals and humans. Particularly, the severe impact on commercial poultry farming has prompted various countries to implement control and mitigation plans to address the damage caused by these viruses. In Mexico, the implementation of vaccination was part of the comprehensive strategies to prevent and control highly pathogenic H5N1 avian influenza outbreaks. For this reason, this work aimed to compare antibody levels in production birds before and after vaccination, examining seroconversion and seroprotection after vaccination in two time periods. Serum samples were taken before and after vaccination in 573 Poultry Production Units during the first vaccination period and 205 Poultry Production Units during the second period across various Mexican states. These samples, later, underwent hemagglutination inhibition tests. With the results obtained from serology, comparisons of medians, calculations of seroconversion and seroprotection, as well as logistic regression analysis were performed. As expected, vaccination led to a statistically higher immune response in birds in most of Mexico's states. However, seroconversion and seroprotection rates remained below 80 % during the first evaluation period. Progenitors and commercial posture birds showed better immune responses to vaccination, particularly with vaccines developed through reverse genetics. These results provide valuable insights into the immune response of Mexican domestic birds under the national strategic plan to control the highly pathogenic influenza A H5N1 virus emergency, which will set a precedent to improve the prevention and control of future outbreaks.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100709"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144917767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-19DOI: 10.1016/j.jvacx.2025.100708
Matilde Zornoza-Moreno , Antonio Iofrío de Arce , Jaime J. Pérez-Martín
Background
The Region of Murcia was one the first Spanish regions to implement a universal influenza vaccination campaign for children of 6–59 months during the 2022–2023 season. The main goal of the study was to assess the healthcare professionals (HCPs) attitudes and satisfaction with the second paediatric influenza vaccination campaign in the Region of Murcia, the 2023–2024, and to compare the results with those from the first campaign.
Methods
Cross-sectional, descriptive study carried out during the 2023–2024 vaccination season using an ad-hoc questionnaire to collect information on HCPs (nurses and doctors) attitudes towards influenza vaccination.
Results
Overall, participating HCPs considered that vaccination against influenza in children of 6–59 months was important or very important, with no differences between professional groups, regardless of their own vaccination status. The ease of administration and the general use of the intranasal (LAIV) and intramuscular (IIV) vaccines was good or very good. A higher score of LAIV's general experience was obtained for the 2023–2024 campaign compared with the 2022–2023 campaign (4.7 vs 4.5, p = 0.006). The score for IIV did not change between campaigns (4.0 vs 4.0, p = 0.98). Of all HCPs involved in the 2023–2024 campaign a higher proportion considered that the presence of a doctor was advisable at school vaccination, but not essential compared with the previous one (54.1 % vs 44.7 %, p<0.001).
Conclusions
Influenza vaccination campaign in the Region of Murcia is highly supported by nurses and doctors. The experience gained during the school vaccination makes vaccination teams feel more confident without a doctor.
穆尔西亚地区是西班牙首批在2022-2023年流感季节对6-59个月大的儿童实施普遍流感疫苗接种运动的地区之一。该研究的主要目的是评估穆尔西亚地区医疗保健专业人员（HCPs）对2023-2024年第二次儿科流感疫苗接种运动的态度和满意度，并将结果与第一次运动的结果进行比较。方法在2023-2024年疫苗接种季节进行横断面描述性研究，使用临时问卷收集HCPs（护士和医生）对流感疫苗接种的态度信息。结果总体而言，参与调查的医护人员认为6-59月龄儿童的流感疫苗接种是重要或非常重要的，无论其自身的疫苗接种情况如何，专业组之间没有差异。鼻内（LAIV）和肌内（iv）疫苗的给药简易性和普遍使用情况良好或非常好。与2022-2023年相比，2023-2024年的LAIV总体经验得分更高（4.7 vs 4.5, p = 0.006）。IIV的得分在不同的运动期间没有变化（4.0 vs 4.0, p = 0.98）。在参与2023-2024年运动的所有HCPs中，较高比例的人认为在学校接种疫苗时医生在场是可取的，但与之前相比不是必需的（54.1%对44.7%,p < 0.001）。结论穆尔西亚地区的流感疫苗接种活动得到了护士和医生的高度支持。在学校疫苗接种期间获得的经验使疫苗接种小组在没有医生的情况下感到更有信心。
{"title":"Attitudes and satisfaction of healthcare professionals towards paediatric influenza vaccination in Spain: A follow-up study","authors":"Matilde Zornoza-Moreno , Antonio Iofrío de Arce , Jaime J. Pérez-Martín","doi":"10.1016/j.jvacx.2025.100708","DOIUrl":"10.1016/j.jvacx.2025.100708","url":null,"abstract":"<div><h3>Background</h3><div>The Region of Murcia was one the first Spanish regions to implement a universal influenza vaccination campaign for children of 6–59 months during the 2022–2023 season. The main goal of the study was to assess the healthcare professionals (HCPs) attitudes and satisfaction with the second paediatric influenza vaccination campaign in the Region of Murcia, the 2023–2024, and to compare the results with those from the first campaign.</div></div><div><h3>Methods</h3><div>Cross-sectional, descriptive study carried out during the 2023–2024 vaccination season using an ad-hoc questionnaire to collect information on HCPs (nurses and doctors) attitudes towards influenza vaccination.</div></div><div><h3>Results</h3><div>Overall, participating HCPs considered that vaccination against influenza in children of 6–59 months was important or very important, with no differences between professional groups, regardless of their own vaccination status. The ease of administration and the general use of the intranasal (LAIV) and intramuscular (IIV) vaccines was good or very good. A higher score of LAIV's general experience was obtained for the 2023–2024 campaign compared with the 2022–2023 campaign (4.7 vs 4.5, <em>p</em> = 0.006). The score for IIV did not change between campaigns (4.0 vs 4.0, <em>p</em> = 0.98). Of all HCPs involved in the 2023–2024 campaign a higher proportion considered that the presence of a doctor was advisable at school vaccination, but not essential compared with the previous one (54.1 % vs 44.7 %, <em>p</em> <em><</em> <em>0.001</em>).</div></div><div><h3>Conclusions</h3><div>Influenza vaccination campaign in the Region of Murcia is highly supported by nurses and doctors. The experience gained during the school vaccination makes vaccination teams feel more confident without a doctor.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100708"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-18DOI: 10.1016/j.jvacx.2025.100707
Sylvia Iasulaitis , Alan Demetrius Baria Valejo , Leonardo Ribeiro dos Santos
This study identifies the underlying drivers of vaccine hesitancy by analyzing political factors, perceptions of vaccine safety, socioeconomic characteristics, and communication variables. We created a partisanship score using supervised machine learning algorithms with the random forest method to assess the influence of political orientations on the roots of COVID-19 vaccine rejection attitudes. This score was then tested empirically using sociodemographic data from a public opinion survey conducted with a sample of the Brazilian population. Based on the weight of evidence (WoE), the attribute relevance analysis revealed key characteristics of citizens who rejected the COVID-19 vaccine in Brazil, highlighting perceptions of vaccine safety and political variables. The data showed that citizens more loyal to then-president Jair Bolsonaro, a vocal vaccine skeptic, were less likely to get vaccinated. They also demonstrated higher perceptions of vaccine-related risks and were more prone to believing in conspiracy theories and misinformation surrounding the vaccine. The methodology developed in this study can be applied to other populations globally to better understand the roots of anti-vaccine attitudes, particularly the influence of political factors.
{"title":"The influence of partisanship on the roots of anti-vaccine attitudes in the context of the COVID-19 pandemic","authors":"Sylvia Iasulaitis , Alan Demetrius Baria Valejo , Leonardo Ribeiro dos Santos","doi":"10.1016/j.jvacx.2025.100707","DOIUrl":"10.1016/j.jvacx.2025.100707","url":null,"abstract":"<div><div>This study identifies the underlying drivers of vaccine hesitancy by analyzing political factors, perceptions of vaccine safety, socioeconomic characteristics, and communication variables. We created a partisanship score using supervised machine learning algorithms with the random forest method to assess the influence of political orientations on the roots of COVID-19 vaccine rejection attitudes. This score was then tested empirically using sociodemographic data from a public opinion survey conducted with a sample of the Brazilian population. Based on the weight of evidence (WoE), the attribute relevance analysis revealed key characteristics of citizens who rejected the COVID-19 vaccine in Brazil, highlighting perceptions of vaccine safety and political variables. The data showed that citizens more loyal to then-president Jair Bolsonaro, a vocal vaccine skeptic, were less likely to get vaccinated. They also demonstrated higher perceptions of vaccine-related risks and were more prone to believing in conspiracy theories and misinformation surrounding the vaccine. The methodology developed in this study can be applied to other populations globally to better understand the roots of anti-vaccine attitudes, particularly the influence of political factors.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100707"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-26DOI: 10.1016/j.jvacx.2025.100711
Jimmy R. Lopez , Otto G. Vanderkooi , James D. Kellner , Louis Valiquette , Gaston De Serres , Karina A. Top , Jennifer Isenor , Matthew P. Muller , Monika Naus , Julie A. Bettinger , for the Canadian Immunization Research Network Investigators
The Canadian National Vaccine Safety (CANVAS) network is a participant-centered, active surveillance system that assesses vaccine safety across Canada. Our study examined the safety profile of influenza vaccines administered to children during seven consecutive influenza seasons, from 2013/2014 to 2019/2020, to establish a baseline for health events in vaccinated and unvaccinated children before the COVID-19 pandemic. Data were collected using an online survey after a 7-day period for vaccinated and unvaccinated participants. Descriptive and inferential analyses explored the association between the influenza vaccine and health events, including associated symptoms. The proportion of health events were comparable in vaccinated and unvaccinated children. Adjusted regression models identified no statistical difference in the occurrence of health events assessed. The most frequently reported symptoms were fever, gastrointestinal symptoms (i.e., nausea/vomiting/diarrhea), and cough. Our findings observed low incidence of health events in both vaccinated and unvaccinated groups in this multi-year study.
{"title":"The Canadian National Vaccine Safety (CANVAS) network: Cross-sectional analysis of seasonal influenza vaccine safety in children during the 2013/2014 to 2019/2020 influenza seasons","authors":"Jimmy R. Lopez , Otto G. Vanderkooi , James D. Kellner , Louis Valiquette , Gaston De Serres , Karina A. Top , Jennifer Isenor , Matthew P. Muller , Monika Naus , Julie A. Bettinger , for the Canadian Immunization Research Network Investigators","doi":"10.1016/j.jvacx.2025.100711","DOIUrl":"10.1016/j.jvacx.2025.100711","url":null,"abstract":"<div><div>The Canadian National Vaccine Safety (CANVAS) network is a participant-centered, active surveillance system that assesses vaccine safety across Canada. Our study examined the safety profile of influenza vaccines administered to children during seven consecutive influenza seasons, from 2013/2014 to 2019/2020, to establish a baseline for health events in vaccinated and unvaccinated children before the COVID-19 pandemic. Data were collected using an online survey after a 7-day period for vaccinated and unvaccinated participants. Descriptive and inferential analyses explored the association between the influenza vaccine and health events, including associated symptoms. The proportion of health events were comparable in vaccinated and unvaccinated children. Adjusted regression models identified no statistical difference in the occurrence of health events assessed. The most frequently reported symptoms were fever, gastrointestinal symptoms (i.e., nausea/vomiting/diarrhea), and cough. Our findings observed low incidence of health events in both vaccinated and unvaccinated groups in this multi-year study.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100711"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing the Zika virus (ZIKV) vaccine remains a critical global public health need. This study assessed the safety and immunogenicity of gamma-irradiated Thai ZIKV isolate. Inactivation was confirmed by serial passaging and detection of viral replication using RT-PCR, which demonstrated complete loss of infectivity in ZIKV irradiated with 25 and 50 kGy. Western blotting confirmed that irradiation preserved viral envelope protein antigenicity. BALB/c mice were subcutaneously immunized twice with 25 kGy-irradiated ZIKV, either alone or with alum adjuvant, at two-week intervals. No mortality or local reactions were observed in any group of mice. Antigen-specific IgG and neutralizing antibody titers were measured by ELISA and focus reduction neutralization test, respectively. T cell responses were assessed via intracellular IFN-γ and TNF-α staining by flow cytometry. The irradiated vaccine induced ZIKV-specific antibody and cytokine-producing T cell responses; however, neutralizing antibody titers were low. Mice immunized with irradiated ZIKV combined with alum adjuvant had higher ZIKV-specific antibody titers and T cells producing IFN-γ or TNF-α than those without adjuvant, though differences were not statistically significant. Although the viral integrity and antigenicity remained unchanged, these findings demonstrate that gamma-irradiated ZIKV is non-infectious and immunogenic in mice, supporting its safety profile and the potential for further optimization in future dose-ranging and efficacy studies.
{"title":"Safety and immunogenicity of inactivated Zika virus vaccine by gamma irradiation","authors":"Pumin Sintara , Puttawat Suphaprueksapong , Suwimol Jetawattana , Witthawat Wiriyarat , Yada Akkhawattanangkul , Komgrid Charngkaew , Nusara Chomanee , Jantip Saelee , Artit Wongsa , Thongkoon Priengprom , Boonrat Tassaneetrithep","doi":"10.1016/j.jvacx.2025.100706","DOIUrl":"10.1016/j.jvacx.2025.100706","url":null,"abstract":"<div><div>Developing the Zika virus (ZIKV) vaccine remains a critical global public health need. This study assessed the safety and immunogenicity of gamma-irradiated Thai ZIKV isolate. Inactivation was confirmed by serial passaging and detection of viral replication using RT-PCR, which demonstrated complete loss of infectivity in ZIKV irradiated with 25 and 50 kGy. Western blotting confirmed that irradiation preserved viral envelope protein antigenicity. BALB/c mice were subcutaneously immunized twice with 25 kGy-irradiated ZIKV, either alone or with alum adjuvant, at two-week intervals. No mortality or local reactions were observed in any group of mice. Antigen-specific IgG and neutralizing antibody titers were measured by ELISA and focus reduction neutralization test, respectively. T cell responses were assessed via intracellular IFN-γ and TNF-α staining by flow cytometry. The irradiated vaccine induced ZIKV-specific antibody and cytokine-producing T cell responses; however, neutralizing antibody titers were low. Mice immunized with irradiated ZIKV combined with alum adjuvant had higher ZIKV-specific antibody titers and T cells producing IFN-γ or TNF-α than those without adjuvant, though differences were not statistically significant. Although the viral integrity and antigenicity remained unchanged, these findings demonstrate that gamma-irradiated ZIKV is non-infectious and immunogenic in mice, supporting its safety profile and the potential for further optimization in future dose-ranging and efficacy studies.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100706"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144863327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-18DOI: 10.1016/j.jvacx.2025.100705
Luciana de Souza Fernandes , Carine Ribeiro Pessoa , Roberto Sousa Dias , Cynthia Canedo da Silva , Sérgio Oliveira de Paula
Dengue remains a critical public health issue in endemic areas, with four co-circulating serotypes (DENV-1–4) and no widely accessible vaccine in Brazil. DNA vaccines offer logistical and cost advantages, and cytokine adjuvants may enhance immunogenicity. We engineered a tetravalent DNA vaccine encoding EDIII from all four DENV serotypes in the pVAX1 vector. To improve immune response, plasmids encoding GM-CSF, IL-7, and IL-15 were co-administered. Antigen expression was confirmed via PCR, western blot, and immunofluorescence. Immunogenicity was assessed using lymphoproliferation assays, TNF/IL-10 cytokine profiling, flow cytometry for memory T-cell phenotyping, and plaque reduction neutralization tests (PRNT). EDIII expression was confirmed for all four serotypes. Co-administration with GM-CSF or IL-15 increased splenocyte proliferation. Cytokine analysis showed variable results with Th1-skewed responses in IL-7 and GM-CSF groups, while IL-15 induced a Th2-biased profile. Flow cytometry revealed that GM-CSF + IL-15 most effectively expanded central memory and naïve CD4+ and CD8+ T cells. PRNT demonstrated neutralizing activity against DENV-1, DENV-3, and DENV-4, but no neutralization of DENV-2. This tetravalent DNA vaccine elicited modest antigen-specific humoral and cellular responses. GM-CSF and IL-15 improved T-cell memory phenotypes, although the absence of DENV-2 neutralization highlights the need for further optimization. Our results inform us of the difficulties in using immune modulators as genetic adjuvants for DNA vaccine design.
{"title":"Activation of cellular immune responses using a dengue tetravalent subunit DNA vaccine candidate with different cytokines as adjuvants","authors":"Luciana de Souza Fernandes , Carine Ribeiro Pessoa , Roberto Sousa Dias , Cynthia Canedo da Silva , Sérgio Oliveira de Paula","doi":"10.1016/j.jvacx.2025.100705","DOIUrl":"10.1016/j.jvacx.2025.100705","url":null,"abstract":"<div><div>Dengue remains a critical public health issue in endemic areas, with four co-circulating serotypes (DENV-1–4) and no widely accessible vaccine in Brazil. DNA vaccines offer logistical and cost advantages, and cytokine adjuvants may enhance immunogenicity. We engineered a tetravalent DNA vaccine encoding EDIII from all four DENV serotypes in the pVAX1 vector. To improve immune response, plasmids encoding GM-CSF, IL-7, and IL-15 were co-administered. Antigen expression was confirmed <em>via</em> PCR, western blot, and immunofluorescence. Immunogenicity was assessed using lymphoproliferation assays, TNF/IL-10 cytokine profiling, flow cytometry for memory T-cell phenotyping, and plaque reduction neutralization tests (PRNT). EDIII expression was confirmed for all four serotypes. Co-administration with GM-CSF or IL-15 increased splenocyte proliferation. Cytokine analysis showed variable results with Th1-skewed responses in IL-7 and GM-CSF groups, while IL-15 induced a Th2-biased profile. Flow cytometry revealed that GM-CSF + IL-15 most effectively expanded central memory and naïve CD4+ and CD8+ T cells. PRNT demonstrated neutralizing activity against DENV-1, DENV-3, and DENV-4, but no neutralization of DENV-2. This tetravalent DNA vaccine elicited modest antigen-specific humoral and cellular responses. GM-CSF and IL-15 improved T-cell memory phenotypes, although the absence of DENV-2 neutralization highlights the need for further optimization. Our results inform us of the difficulties in using immune modulators as genetic adjuvants for DNA vaccine design.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100705"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-08-27DOI: 10.1016/j.jvacx.2025.100715
Martin Novák , Jana Zibolenová , Peter Vyšehradský , Romana Ulbrichtová , Eva Malobická , Eliška Štefanová , Ján Mikas , Adriana Mečochová , Henrieta Hudečková , Viera Švihrová
Introduction
The resurgence of vaccine-preventable diseases poses a significant global public health challenge, exacerbated by the rise of anti-vaccination attitudes. The aim of this study was to validate the Slovak version of the Vaccination Attitudes Examination (VAX) questionnaire and to examine the attitudes towards vaccination in Slovakia.
Methods
The VAX scale questionnaire, translated into Slovak and validated, was used for the survey. The VAX scale uses 12 statements assessing anti-vaccination attitudes. Each statement is scored on a 6-point Likert scale, with higher total score indicates more negative attitudes towards vaccinations. Our questionnaire also included demographic questions (age, gender, residence, education level, profession, and economic activity). For validation, the questionnaire was translated into the Slovak using forward and backward translations. The validation survey was conducted on the sample size of 115 participants. Correlation was calculated using Pearson's correlation coefficient, internal consistency was tested. Confirmatory factor analysis (CFA) was performed to assess validity. Subsequently, a pilot study was conducted in March 2023 with a sample size of 473 participants.
Results
The VAX scale demonstrated strong internal consistency (Cronbach's alpha = 0.925) and reliability. The results of the CFA were comparable to findings from other languages versions. The pilot study revealed that parents, non-healthcare professionals, and older individuals exhibited higher anti-vaccination attitudes. In contrast, healthcare professionals had the lowest VAX scores, reflecting more pro-vaccination attitudes.
Conclusion
These findings highlight the need for targeted educational and communication strategies to address vaccine hesitancy. By identifying demographic patterns and potential hotspots of vaccine skepticism, public health initiatives can be better tailored to improve vaccination rates. The validated Slovak VAX scale provides a reliable tool for ongoing assessment and intervention efforts.
{"title":"The validation of the Slovak vaccination attitudes examination (VAX) scale and pilot study","authors":"Martin Novák , Jana Zibolenová , Peter Vyšehradský , Romana Ulbrichtová , Eva Malobická , Eliška Štefanová , Ján Mikas , Adriana Mečochová , Henrieta Hudečková , Viera Švihrová","doi":"10.1016/j.jvacx.2025.100715","DOIUrl":"10.1016/j.jvacx.2025.100715","url":null,"abstract":"<div><h3>Introduction</h3><div>The resurgence of vaccine-preventable diseases poses a significant global public health challenge, exacerbated by the rise of anti-vaccination attitudes. The aim of this study was to validate the Slovak version of the Vaccination Attitudes Examination (VAX) questionnaire and to examine the attitudes towards vaccination in Slovakia.</div></div><div><h3>Methods</h3><div>The VAX scale questionnaire, translated into Slovak and validated, was used for the survey. The VAX scale uses 12 statements assessing anti-vaccination attitudes. Each statement is scored on a 6-point Likert scale, with higher total score indicates more negative attitudes towards vaccinations. Our questionnaire also included demographic questions (age, gender, residence, education level, profession, and economic activity). For validation, the questionnaire was translated into the Slovak using forward and backward translations. The validation survey was conducted on the sample size of 115 participants. Correlation was calculated using Pearson's correlation coefficient, internal consistency was tested. Confirmatory factor analysis (CFA) was performed to assess validity. Subsequently, a pilot study was conducted in March 2023 with a sample size of 473 participants.</div></div><div><h3>Results</h3><div>The VAX scale demonstrated strong internal consistency (Cronbach's alpha = 0.925) and reliability. The results of the CFA were comparable to findings from other languages versions. The pilot study revealed that parents, non-healthcare professionals, and older individuals exhibited higher anti-vaccination attitudes. In contrast, healthcare professionals had the lowest VAX scores, reflecting more pro-vaccination attitudes.</div></div><div><h3>Conclusion</h3><div>These findings highlight the need for targeted educational and communication strategies to address vaccine hesitancy. By identifying demographic patterns and potential hotspots of vaccine skepticism, public health initiatives can be better tailored to improve vaccination rates. The validated Slovak VAX scale provides a reliable tool for ongoing assessment and intervention efforts.</div></div>","PeriodicalId":43021,"journal":{"name":"Vaccine: X","volume":"26 ","pages":"Article 100715"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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