Vaccines最新文献

Background/Objectives: The rise of immune escape variants of the SARS-CoV-2 virus has prompted the development of vaccines based on the variant's spike antigen sequence. Since variant-specific SARS-CoV-2 vaccines are mostly administered as boosters to individuals previously vaccinated with reference (Ref.) strain-based vaccines, a better understanding of their immunogenicity in this context is essential. Protein subunit vaccines have a well-established track record of safety. Herein, we assessed the ability of variant-specific protein subunit vaccine formulations to boost pre-existing Ref. strain-specific immune responses compared to boosting with a Ref. strain-specific formulation in young and aged female Balb/c mice. Methods: Following a priming vaccination series with Ref. spike protein adjuvanted with sulfated lactosyl archaeol (SLA) archaeosomes on days 0 and 21, immune responses were evaluated in young and aged female Balb/c mice. On day 91, mice received a third immunization with Ref., Beta, or Delta spike protein formulations, with or without SLA archaeosomes. Antibody titers, neutralization activity, and cellular immune responses were measured to assess the impact of the booster formulation. Results: Aged mice exhibited lower antibody titers throughout the study and a decline over time compared to young mice. After a third immunization, responses were boosted by all vaccine formulations (Ref., Beta, or Delta), with or without adjuvant. However, variant-specific antigen formulations did not overcome immune imprinting from the priming series or increase neutralization activity against the corresponding SARS-CoV-2 variants in either age group. Conclusions: Variant-specific protein subunit vaccines enhanced immune responses but did not overcome immune imprinting induced by the Ref. strain's priming. The inclusion of SLA archaeosomes improved cellular immunity, supporting their potential role in optimizing booster vaccine performance, particularly in aged populations.

Background: Socioeconomic disparities may affect COVID-19 booster vaccination uptake, potentially undermining public health efforts. This study assessed the association between first booster dose coverage and municipal socioeconomic deprivation in the Apulia region of southern Italy. A secondary objective was to evaluate whether SARS-CoV-2 incidence modified this relationship. Methods: We conducted a retrospective observational study including Apulian residents aged ≥5 years from 1 January 2021, to 31 December 2022. First booster doses were identified using an algorithm based on dose chronology and national guidelines. Vaccination and infection data were retrieved from regional databases. Socioeconomic deprivation was measured using the Social and Material Vulnerability Index (SMVI) developed by the Italian National Institute of Statistics (ISTAT). Booster coverage was calculated at the municipal level. A multivariable Poisson's regression model was used to estimate the association between SMVI and booster uptake, adjusting for age group, primary vaccine type, SARS-CoV-2 incidence, and municipal vaccination rates. Analyses were stratified by sex. Results: A total of 2,732,258 individuals received a first booster dose. Booster coverage decreased with increasing SMVI. Among females, a significant reduction was observed in the highest deprivation category (RR > 102 vs. <99: 0.95; 95% CI: 0.94-0.97) and it was similar in males (RR: 0.95; 95% CI: 0.93-0.96). A significant interaction between age and deprivation was found in both sexes, with a sharper decline in younger individuals. Municipal vaccination rates were positively associated with booster uptake. SARS-CoV-2 incidence was positively associated with uptake only in males. Conclusions: The analysis revealed a significant association between lower socio-cultural level and lower adherence to the first booster dose of the COVID-19 vaccine. The decline is more pronounced among subjects younger than 50 years with high levels of vulnerability. The findings of this study suggest that to overthrow vaccine hesitancy, knowledge of the social setting allows for targeted communications to the different groups in the population. Further research is needed to define different approaches in the different social groups.

Background/objectives: To estimate (a) survival after SARS-CoV-2 infection by COVID-19 vaccination status, and (b) COVID-19 vaccine effectiveness in a middle-income country.

Methods: In this retrospective cohort study, secondary analysis of data from the national surveillance and vaccination databases was conducted. The primary outcome was COVID-19 death classified based on the WHO criteria. Data were analysed by vaccination status, age, sex, geographic region, and wave period. Kaplan-Meier curves were plotted; log-rank followed by multiple comparison tests were used to compare survival probabilities. Cox proportional-hazards models with time-varying covariates estimated hazard ratios (HR). Vaccine effectiveness was computed as (1-HR) × 100.

Results: A total of 55,299 COVID-19 cases were captured by the national surveillance system between 1 April and 31 December 2021. Of these, 45,774 (1581 vaccinated, 44,193 unvaccinated) were included in the analysis. After a follow-up of 327 days, there were 22 deaths (case fatality rate (CFR) 1.5%) among 1581 COVID-19 vaccinated cases and 1821 deaths (CFR 4.1%) among 44,193 unvaccinated cases. There was one COVID-19 death per 10,000 person days in vaccinated cases compared with 2.7 COVID-19 deaths per 10,000 person days in unvaccinated cases. After adjustment for age, sex, and geographic region, the effectiveness against COVID-19 death across all vaccine types (ChAdOx1 nCoV-19, BNT162b2, Ad26.COV2.S, or BBIBP-CorV) was 68% (95% CI: 51-79). Effectiveness was 75% (95% CI: 59-84) for ChAdOx1 nCoV-19. Vaccine effectiveness across all vaccine types was higher in younger cases, (82% (95% CI: 52-93), 18-64 years vs. 63% (95% CI: 41-77), ≥65 years), females (84% (95% CI: 63-93), females vs. 53% (95% CI: 24-71), males) and those vaccinated in the past 3 months (71% (95% CI: 47-85), past 0-3 months vs. 56% (95% CI: 23-75), 3-6 months).

Conclusions: COVID-19 vaccines were effective in preventing COVID-19 death in a population with low vaccination coverage. Limitations of the analysis include the use of surveillance data (under-reporting of cases, missing data), exclusion of partially vaccinated cases, and insufficient data on important confounders (circulating variants and comorbidities).

Background/Objectives: Despite global efforts, COVID-19 revealed severe spatial vaccine inequities, disproportionately affecting low- and middle-income countries (LMICs). Scholars across disciplines proposed numerous-and often competing-terms and theories to explain these disparities. In this review and within the context of the COVID-19 pandemic, we assess the usage, definition, and appropriateness of these terms and their linked theories or frameworks. Methods: We conducted a scoping review aiming to clarify key definitions, concepts, and frameworks of eight prominent terms used in the literature regarding COVID-19 global and/or regional vaccine inequities (i.e., vaccine nationalism, vaccine apartheid, vaccine colonialism, vaccine imperialism, vaccine racism, vaccine diplomacy, vaccine solidarity, and vaccine internationalism). The methodology followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines for Scoping Reviews and included papers from January 2020 to the end of October 2024. Results: We included 79 papers in our study. The majority (71%) were published in 2021-2022, with less than one-quarter authored by scholars from LMICs. Vaccine imperialism was consistently defined but rarely used, while vaccine nationalism and vaccine apartheid appeared more frequently with varied meanings. Yet, in most cases, all of these concepts identified economic interests of vaccine-producing countries as the root cause of the observed vaccine inequities. Vaccine diplomacy showed similar ambiguity, viewed by some as worsening inequities and by others as potentially mitigating them. The terms vaccine racism, vaccine colonialism, and vaccine solidarity were not explicitly identified but appear to be embedded within the definitions of other prominent terms detected. Conclusions: Across the preselected terms examined, we found numerous-and often conflicting-definitions, revealing the fragmented and competing understandings of the major drivers fueling global vaccine inequities. This lack of coherence inhibits evidence synthesis or shared theoretical progress but, most importantly, might undermine current and future efforts to address these inequities.

The global response to SARS-CoV-2 has advanced at unprecedented speed: vaccines developed in record time, mass immunization campaigns, and real-world data confirming reductions in severe disease and death [...].

Background/Objectives: Seasonal influenza is a global public health issue, and influenza vaccination is the most effective preventive measure. Nursing students are at a higher risk of contracting it due to clinical exposure. However, vaccination uptake among nursing students remains low. This study examines seasonal influenza vaccination uptake rates and the predictors of nursing students' willingness to receive this vaccine. Methods: A cross-sectional online study was conducted using a well-validated questionnaire in order to collect data from a convenience sample of nursing students in Hong Kong from early November to early December 2024. Results: Out of the 461 valid responses received, 67.5% were from females, with a mean age of 20.53 (SD = 2.16) years. Vaccination history was diverse: 34.3% reported that they underwent influenza vaccination in the most recent season, 49.7% reported that they were vaccinated one to two times over the preceding five years, and only 5% reported that they undergo vaccination annually. A logistic regression model showed that the respondents who had been vaccinated against influenza in the most recent years (OR = 2.881, 95% CI: 1.773-4.680) had been vaccinated against influenza 1-2 times (OR = 3.239, 95% CI: 1.750-5.993), had been vaccinated 3-4 times (OR = 3.984, 95% CI: 1.773-8.957), had been vaccinated every year (OR = 10.353, 95% CI: 3.025-35.436) in the past five years, and had a higher score of perceived susceptibility (OR = 2.244, 95% CI: 1.302-3.867) were more likely to intend to be vaccinated with an influenza vaccine in the coming year. Conclusions: Annual seasonal influenza vaccination rates among nursing students remain low, though they have improved. We recommend that the Hong Kong government, healthcare organizations, and universities develop effective strategies for promoting annual seasonal influenza vaccination to safeguard both patients' health and the health of future nursing professionals.

Background: Despite pre-transplantation vaccination against invasive pneumococcal disease (IPD) and hepatitis B virus (HBV), most solid organ transplant (SOT) recipients are without post-transplantation seroprotection against IPD and HBV. We aimed to determine the seroprotection rates and changes in antibody concentrations after booster vaccination against IPD and HBV in SOT recipients without post-transplantation seroprotection after pre-transplantation vaccination. Furthermore, we aimed to identify risk factors associated with non-response to booster vaccination.

Methods: In this prospective cohort study, we included adult SOT recipients without post-transplantation seroprotection against IPD who then received the 23-valent pneumococcal polysaccharide vaccine (PPSV23) booster, as well as adult SOT recipients without seroprotection against HBV who then received the Engerix-B^® booster after pre-transplantation vaccination. Logistic regression models were used to analyze risk factors for non-response to booster vaccination.

Results: We included 50 SOT recipients in analyses of booster vaccination against IPD and 52 SOT recipients in analyses of booster vaccination against HBV. Seroprotection rates were 52% after booster vaccination against IPD and 7.7% after booster vaccination against HBV. The median geometric mean concentration of pneumococcal antibodies increased from 0.54 µg/mL IgG (interquartile range, IQR: 0.35-0.77) to 1.21 µg/mL IgG (IQR: 0.87-1.62) after booster vaccination (p < 0.001). Having pre-transplantation seroprotection against IPD at time of listing was associated with lower odds of non-response to booster vaccination. We were not able to identify risk factors for non-response to HBV booster vaccination.

Conclusions: Booster vaccination improved seroprotection against IPD, but not HBV. Further studies are needed to examine optimal vaccination strategies for SOT recipients.

Background: Influenza presents significant risks to older adults; however, vaccination coverage in China remains low despite robust recommendations. Factors such as vaccine hesitancy, physician recommendations, health status, and socioeconomic conditions influence vaccination rates. This study uses large-scale influenza vaccination data from urban older adults in six cities and applies structural equation modeling to investigate the determinants of both influenza vaccination uptake and future intention. Methods: A cross-sectional survey was conducted from December 2024 to January 2025 across six major Chinese cities, involving 13,363 community-dwelling adults aged ≥60 years. Vaccine hesitancy was measured using the validated 5C scale. Structural equation modeling with weighted least squares mean and variance adjusted estimation was employed to assess direct and indirect effects of physician recommendation, socioeconomic status, medical status, and subjective health on influenza vaccination uptake. Results: The vaccination uptake rate is 34.05%, while the intention rate is 32.20%. Vaccine hesitancy is the strongest negative predictor of vaccination (β = -0.488, p < 0.001). Physician recommendation has the largest total effect (β = 0.351), with 45.60% of this effect mediated through reduced vaccine hesitancy. Medical status is directly associated with lower uptake; it consistently promoted intention. Higher socioeconomic status also positively affected vaccination (total effect = 0.167), partly via lower hesitancy. Conclusions: Vaccine hesitancy serves as a pivotal mediator in influenza vaccination uptake and intention among Chinese older adults. Strengthening physician recommendations and addressing socioeconomic disparities are key strategies to reduce hesitancy and improve coverage.

Background: Inactivated enterovirus 71 (EV71) vaccines play a vital role in preventing severe cases of hand, foot, and mouth disease, with their quality and stability determined by the degree of viral particle aggregation.

Objective: This study aimed to use dynamic light scattering (DLS) for monitoring EV71 particle size, comprehensively evaluate the effects of environmental stresses on viral aggregation, and identify suitable stabilizing agents.

Methods: The DLS technique was validated. Using this method, the effects of pH, ionic strength, freeze-thaw cycles, temperature, and mechanical stresses on viral particle size were assessed. Additionally, the ability of different buffer salts and stabilizers to inhibit stress-induced aggregation was systematically evaluated.

Results: The DLS method exhibited robust performance. EV71 particles were stable at pH 7.0-7.5. Exposure to 47 °C and magnetic stirring promoted viral aggregation. Phosphate buffer and citrate buffer exhibited the highest inhibitory effects on heat-induced aggregation and stirring-induced aggregation, respectively. M199 and Tween 80 efficiently mitigated heat-induced particle aggregation and shear stress-induced particle aggregation, respectively.

Conclusions: This study demonstrated the performance of DLS in viral aggregation monitoring. Additionally, this study revealed tailored stabilization strategies, providing key insights for vaccine formulation and quality control.