Search Results (3,684)

Background: Solid organ transplant recipients (SOTRs) are highly vulnerable to severe COVID-19 infection, yet initial vaccine trials provided limited data on efficacy and safety in this immunocompromised population. Heterogeneous seroconversion rates and conflicting safety reports complicate the formulation of clear clinical guidelines. This systematic review and meta-analysis aim to aggregate existing evidence to determine the precise seroconversion and safety profiles of COVID-19 vaccines and identify key factors influencing immune response in SOTRs. Methods: A comprehensive literature search was conducted identifying 125 studies evaluating WHO/FDA-authorized vaccines in SOTRs. Outcomes were the pooled seroconversion proportion and safety profile. Subgroup analyses were performed based on vaccine type, transplanted organ, number of doses, and prior SARS-CoV-2 infection status, confirmed by leave-one-out sensitivity analysis and bootstrap methods. Results: Most studies assessed mRNA-based vaccines (123/125, 98.4%). The overall pooled seroconversion proportion across all SOTRs was significantly blunted at 0.49 (95% CI, 0.43 to 0.55), demonstrating high heterogeneity (I² = 94.2%). Seroconversion showed a clear positive dose–response relationship, increasing from 27% after one dose to 84% after four doses. Prior COVID-19 infection was the strongest predictor of a response, resulting in a pooled seroconversion of 0.90 (95% CI, 0.82 to 0.94; I² = 0%). Organ-specific analyses revealed the highest response in Liver recipients (0.80) and the lowest in Lung recipients (0.29). Vaccine platform analysis showed that the highest response was with mRNA-1273 (0.55) and the lowest with CoronaVac (0.29). The safety profile was limited. Conclusions: SOTRs exhibit profound hypo responsiveness to COVID-19 vaccines; however, the extreme heterogeneity observed across studies necessitates a cautious interpretation of pooled seroconversion estimates. While the data indicates a significant dose–response relationship favoring an aggressive, multi-dose strategy, the apparent safety profile may reflect under-reporting and limited follow-up rather than confirmed safety equivalence. Rare but clinically critical outcomes, such as acute allograft rejection, remain inadequately characterized in the current literature. Consequently, while the prioritization of multi-dose regimens and hybrid immunity is supported to maximize protection, clinicians must recognize that individual responses remain highly variable, and the long-term immunological impact of repeated stimulation requires further standardized investigation. Full article

Objective: In the context of an aging population, the prevention and control of cognitive impairment is a key public health priority. This study aims to investigate the association between proactive health behaviors and the risk of AD8 screening positivity in older adults in China, providing an empirical basis for developing targeted intervention strategies. Methods: Based on health behavior data from 1110 older adults in China, the chi-square test was used to analyze the differences in proactive health behaviors (such as limiting salt and alcohol intake, smoking cessation, and vaccination) between the low-risk and high-risk groups for AD8 screening. Factor analysis was used to extract the main factors of proactive health behaviors. Firth penalized logistic regression models were used to analyze the impact of the main factors and sociodemographic factors on the risk of cognitive impairment. Results: The chi-square test showed that there were significant differences between the two groups in salt restriction behavior (χ² = 18.063, p < 0.01) and vaccination (χ² = 29.674, p < 0.01), with a higher proportion of salt restriction (34.7%) and vaccination rates (80.4%) in the low-risk group. Factor analysis extracted four main factors (psychological–social support, information–behavior execution, technology–environment promotion, and addictive behavior control), with a cumulative variance contribution rate of 58.45%. Among them, psychological–social support (31.42% explained variance) and information–behavior execution (28.04%) had the strongest explanatory power. Firth penalized logistic regression showed that psychological–social support (Firth-corrected OR = 0.072, 95% CI: 0.035–0.148, p < 0.01) and information–behavior execution (Firth-corrected OR = 0.008, 95% CI: 0.003–0.021, p < 0.01) had significant protective effects on AD8 screening positivity (standardized OR values indicated that each one-standard-deviation increase in these two factors reduced screening-positive risk by 39% and 53%, respectively), and the risk increased by 21.7% for every 5-year increase in age (OR = 1.217, p = 0.001). Technology–environment promotion (OR = 0.417, 95% CI: 0.250–0.691, p = 0.001) and addictive behavior control (OR = 0.709, 95% CI: 0.490–1.026, p = 0.068) showed no significant protective effects. Sensitivity analysis confirmed the robustness of the four-factor structure and core conclusions. Conclusions: Among proactive health behaviors, psychological–social support and information–behavior execution are key protective factors in reducing the risk of AD8 screening positivity in older adults, and age is an important influencing factor. Strengthening psychological support and optimizing access to health information and behavior execution can serve as core strategies for cognitive impairment prevention and control, providing empirical support for the formulation of health policies for older adults. Full article

The Coronavirus Disease 2019 (COVID-19) pandemic and its prolonged effects have been widely discussed on social media, and these discussions have been analyzed in various studies. A long-term analysis of Twitter (now “X”) posts regarding COVID-19 vaccination is essential for informing policy and improving public health communication strategies. In addition, to prevent the spread of infectious diseases, it is crucial to rapidly promote vaccination while mitigating the impact of negative sentiment toward vaccination on social media platforms. Therefore, identifying the key factors behind negative discussions is important for guiding policy decisions and shaping responses. In this study, we collected Japanese tweets (posts) containing the words “Corona” and “vaccine” that were posted from February 2021 to December 2022. The results indicate that negative sentiment was primarily driven by concerns about adverse reactions and general fear and anxiety, which were particularly prominent before vaccination for the general public began, as well as mentions of pain during and after vaccination. While concerns about adverse reactions persisted throughout the analysis period, their prominence decreased over time as positive reactions became more frequent. Our findings provide insights into the characteristics and key factors behind negative discussions on COVID-19 vaccination in the Japanese context and may help improve public health communication strategies. Full article

Background and objectives: During an outbreak, measles cases tend to aggregate into increasingly bigger clusters that show specific characteristics, different from the non-cluster cases. As the measles threat continues throughout Europe in 2025 with a high notification rate in Romania as well, exploring how clustering affects the disease propagation can provide additional insights into how to improve measles surveillance and control. Methods: National measles cases from 2020 to 2024 have been split into cluster (at least three related cases) and non-cluster-related cases and analyzed comparatively based on vaccination status, disease-related data (hospitalization) and patient-related data (age, location). Large outbreaks with at least 150 cases, allowing for more comprehensive R₀ analysis, have been described and the basic reproduction numbers computed for each of them. Results: There are statistically significant differences in vaccination status, age, and hospital stay between outbreak and non-outbreak cases. Large outbreaks (≥150 cases) show a high degree of variability, with R₀ values varying from as low to 1 to as high as 3.92, indicating limited measles transmission control. Conclusions: The findings in this research highlight the critical impact of clustering on measles transmission dynamics during outbreaks. Significant differences in vaccination status, age, and hospitalization rates between cluster and non-cluster cases underscore the importance of targeted surveillance and intervention strategies while the wide range of R₀ values observed in large outbreaks points to inconsistent control measures and emphasizes the need for strengthened vaccination campaigns and improved outbreak response protocols to better contain measles spread. Full article

Despite screening programs and vaccination campaigns, cervical cancer (CC) remains a health problem worldwide. The involvement of the E6 and E7 oncoproteins of Human Papillomavirus (HPV) is crucial for the development and progression of this type of cancer. Metabolic reprogramming by cancer cells has gained relevance in the last decade due to its ability to promote cell growth, survival, invasion, metastasis, and resistance to therapy. In this review, we focus on alterations in cholesterol metabolism that significantly influence the development and progression of CC, as well as the clinical outcome of patients. Furthermore, evidence from comprehensive omics studies suggesting that E6 and E7 are involved in the exacerbation of elements related to cholesterol metabolism is analyzed. Preclinical and clinical studies are also discussed that demonstrate that cholesterol metabolism is a potential therapeutic target, highlighting its impact on reducing tumor growth, altering the tumor microenvironment, and improving antitumor immunity. Full article

Patients with inflammatory bowel disease (IBD) frequently fail to achieve protective immunity after hepatitis B vaccination, even with intensified vaccination schedules. In this observational real-world study, 18 patients with IBD who were seronegative for hepatitis B virus (HBV) received three standard doses of the Engerix-B^® vaccine (at 0, 1, and 6 months). After immunisation, patients were classified into responders and non-responders according to their serological response. Blood samples were collected before the first dose and after completion of the vaccination schedule. Responders activated pathways that supported durable protection, including conventional dendritic cells type 1 mobilisation, expansion of IgG plasmablasts, and preservation of B- and T-cell memory. In contrast, non-responders displayed a more inflammatory innate profile, characterised by enrichment of CCR2⁺ monocytes. They also showed higher baseline Treg frequencies, which may suppress effective effector responses, together with impaired natural killer (NK) activation and progressive loss of memory potential. This study shows that hepatitis B vaccine failure in inflammatory bowel disease reflects a convergence of excessive immune regulation, inflammatory activation, and loss of memory potential, underscoring that no single pathway can explain the impaired response. Full article

Monkeypox (MPOX) is an emerging zoonotic disease caused by monkeypox virus (MPXV), an orthopoxvirus closely related to smallpox. Initially confined to endemic regions in Central and West Africa, MPOX has recently gained global significance with outbreaks reported across multiple continents. MPXV is maintained in animal reservoirs but is increasingly transmitted from person to person, facilitated by close contact, respiratory droplets, and, in some cases, sexual transmission. Clinically, MPOX presents with fever, lymphadenopathy, and a characteristic vesiculopustular rash, though atypical manifestations have been observed in recent outbreaks, complicating diagnosis. Laboratory confirmation relies on molecular testing, while differential diagnosis must consider varicella, herpes, and other vesicular illnesses. Therapeutic options remain limited; supportive care is the cornerstone of management, but antivirals such as tecovirimat and brincidofovir, as well as smallpox vaccines, have shown efficacy in mitigating disease severity and preventing infection. The unprecedented global outbreak has underscored the importance of surveillance, rapid diagnostics, and coordinated public health responses to contain transmission. This review provides an overview of epidemiology, virology, clinical manifestations, modes of transmission, available diagnostics, and prophylactic and therapeutic strategies against MPOX. We also discuss the role of animal reservoirs, viral evolution, and human-to-human transmission in shaping the dynamics of recent MPOX outbreaks. By summarizing the latest evidence, this review aims to inform clinicians, researchers, and policymakers about key aspects of MPOX biology, clinical management, and prevention, while identifying gaps that warrant future investigation for the control of this and potentially other emerging zoonotic-related pathogens with an impact on human health. Full article

Group A rotaviruses (RVAs) remain the leading cause of acute gastroenteritis (AGE) in young children in low- and middle-income countries. In Brazil, the oral attenuated RVA vaccine (Rotarix^®), monovalent genotype G1P[8], is distributed by the national immunization program and has drastically reduced morbidity and mortality associated with RVA etiology. In this study, Rotarix^® G1P[8] was detected using specific qRT-PCR from the fecal shedding of children living in the Amazon region, and 18.3% (29/158) were positive and 75.8% (22/29) presented with AGE. The VP4 (VP8*) gene of these sheddings, submitted to Sanger nucleotide sequencing, showed an occurrence of mutations, including the silent mutation at 144C > G (one child) and the following missense mutations— 499T > C (F167L) (two children), 644G > C (C215S) (one child), and 787G > A (E263K) (one child). These mutations had no impact on the protein model structure in silico deduced from the VP4 (VP8*) mutants. The in silico protein model deduced from the VP4 (VP8*) nucleotide sequences, bound to type 1H sugar antigens (H1) and its precursor Lac-para-N-biose (LNB), had a stronger binding to the G1P[8] genotype, when compared to G3P[8]. Rotarix^® shedding was higher in HBGA secretors than in non-secretors (79.3%; 23/29). A total of 11.4% (18/158) of children with Rotarix^® G1P[8] shedding were unvaccinated, indicating the occurrence of indirect protection. Stability evidence of Rotarix^® VP4 (VP8*) spike protein from samples collected in vivo is presented. Full article

Background: West Nile Virus (WNV) is a mosquito-borne flavivirus responsible for seasonal outbreaks in temperate and tropical regions, including Europe, the Mediterranean, and the Middle East. Its transmission via mosquitoes, particularly Culex species, poses persistent challenges to public health. Despite ongoing efforts, comprehensive prevention and treatment strategies remain limited. Methods: A comprehensive search of peer-reviewed literature, clinical trials, and government surveillance data from Italy and Iran was conducted using PubMed, Scopus, Web of Science, and supplementary web-based resources. Inclusion criteria focused on molecular studies of WNV, vaccine and antiviral drug development, and regional outbreak reports. Results: WNV transmission is influenced by climatic conditions, as well as vector distribution and ecological patterns. While human vaccines are currently under development, only veterinary vaccines yielded promising but still limited evidence of effectiveness. Notably, therapeutic measures are currently limited to supportive care, whereas investigational antiviral drugs are in early-stage trials. Interestingly, Italy demonstrates robust surveillance with regular reporting of outbreaks, whereas data from Iran indicate that despite a widespread serological footprint, especially in southern and southwestern provinces, the reported clinical impact on humans and animals appears comparatively less severe. Conclusions: Bridging gaps in vaccine availability, therapeutic innovation, and disease monitoring is essential for effective WNV management to prepare for potential severe future outbreaks in Europe and the Middle East. On the other hand, regional differences between Italy and Iran reveal the need not only for tailored public health interventions and enhanced surveillance, but also for sustained investment in research. In our view, collaborative frameworks across Mediterranean and Middle Eastern countries in a “One Health” approach may improve preparedness and response to future WNV outbreaks. Full article

Leishmaniasis is an infectious disease caused by several species of Leishmania parasites that preferentially infect macrophages as host cells. These intracellular parasites can evade the main microbicidal effector mechanisms of phagocytic cells and, in turn, are able to stimulate marked Th2 or regulatory T cell immune responses, which are not protective for the host. The presence of a non-protective immune response, together with the multiplication and spread of Leishmania parasites throughout the tissues, leads to the main clinical forms of leishmaniasis, such as cutaneous and visceral leishmaniasis. Although some clinical forms can be reproduced in experimental hosts such as mice and hamsters, these models do not fully mimic natural infection, which, in fact, impacts experimental vaccine development. For example, BALB/c mice are generally infected with around one million parasites, whereas humans are not infected with more than 1000 parasites, together with vector saliva. This excessive number of parasites in experimental models may affect the efficacy of vaccines in preclinical studies. Indeed, many experimental studies conducted over the past 20 years have shown only partial protection, regardless of the vaccine generation, host species employed, or the use of adjuvants. This review aims to summarize the main aspects associated with Leishmania vaccine development, including parasite diversity, host factors, immune responses, adjuvants, and antigens. Although many elegant studies have been conducted, it is possible that some essential step is still missing for the development of an effective vaccine for human use. Full article

An age-distributed immuno-epidemiological model with information-based vaccination proposed in this work represents a system of integro-differential equations with compartments for the numbers of susceptible individuals, infected individuals, vaccinated individuals, and recovered individuals. This model describes the influence of vaccination decisions on epidemic progression in different age groups. In a particular case of the model without age distribution, we determine the basic reproduction number and the final size of epidemic, that is, the limiting number of susceptible individuals at asymptotically large time. Moreover, we study the existence and uniqueness of a positive solution for the age-structured model. Numerical simulations show that the information-based vaccination acceptance can significantly influence the epidemic progression. Though the initial stage of epidemic progression is the same for all memory kernels, as the epidemic progresses and more information about the disease becomes available, further epidemic progression strongly depends on the memory effect. A short-range memory kernel appears to be more effective in restraining the epidemic outbreaks because it allows for more responsive and adaptive vaccination decisions based on the most recent information about the disease. Additionally, the simulation results suggest that relying on either a responsive vaccination approach or a highly effective vaccine alone may be insufficient to significantly reduce the epidemic size and prevent large outbreaks. Both factors are necessary to achieve substantial epidemic control. Moreover, the impacts of the age-dependent initial susceptible population and the age-dependent memory kernel are studied through numerical simulation of the age-dependent model. Full article

Background/Objectives: Viral hepatitis remains a significant global cause of chronic liver disease, highlighting the importance of effective vaccination strategies. This review assesses recent evidence on vaccine safety and effectiveness. Methods: A comprehensive search of PubMed, Embase, Web of Science, and Scopus identified English-language studies published from January 2000 to September 2025. Eligible studies evaluated vaccination for hepatitis A, B, C, or E, as well as vaccine responses in individuals with chronic liver disease or HIV infection. Of 5254 records screened, 166 studies met the inclusion criteria. Results: Hepatitis A vaccines demonstrated excellent safety, 95–100% short-term seroprotection, and durable immunity for both inactivated and live-attenuated formulations, with population-level reductions in disease incidence. Hepatitis B vaccines showed consistently strong immunogenicity across age groups, with over 90% seroprotection from recombinant and CpG-adjuvanted formulations. Effective prevention of mother-to-child transmission required maternal antiviral therapy, timely birth-dose vaccination, hepatitis B immunoglobulin (HBIG) administration, and post-vaccination serologic testing. Long-term data demonstrated immune persistence for up to 35 years and significant reductions in liver cancer following neonatal HBV vaccination. Limited studies in hepatitis C populations showed impaired responses, partially improved with higher or booster doses. Hepatitis E vaccines showed excellent safety and over 99% seroconversion. In non-viral liver disease and post-transplant populations, vaccine responses were reduced but remained clinically meaningful, especially with adjuvanted or higher-dose HBV vaccines. Among HIV-infected individuals, HAV vaccination was generally effective, while enhanced HBV regimens markedly improved seroprotection. Conclusions: Hepatitis A, B, and E vaccines are safe, immunogenic, and effective, with neonatal hepatitis B vaccination critical for preventing maternal transmission. No licensed HCV vaccine exists, and therapeutic HCV vaccines show limited efficacy. Optimized and targeted vaccination strategies are needed for individuals with chronic liver disease, HIV infection, HCV infection, transplant recipients, and other immunocompromised populations to maximize public health impact. Full article

Vaccination is a tool to control Lawsonia intracellularis (LI) in pigs. However, pigs may have co-infections that worsen clinical signs and lesions. The aim of this study was to characterize systemic and gut-mediated humoral and cell-mediated immune (CMI) responses in pigs vaccinated with a killed intramuscular LI vaccine and to analyze the impact of co-infection with Brachyspira hyodysenteriae (Bhyo) on the immune response. The study included eighty pigs and five study groups: V-CO (LI-vaccinated and co-infected with LI + Bhyo, n = 21), P-CO (placebo and co-infected with LI + Bhyo, n = 18), V-LI (LI-vaccinated and infected with LI, n = 21), P-LI (placebo and infected with LI, n = 12), and NC (negative control, placebo and non-challenged, n = 8). Parameters analyzed: fecal score and pathogen shedding), gross intestinal lesions, LI intestinal colonization (IHC), serum IgG, LI-specific IFN-γ production (ELISPOT), and immune cell subsets (flow cytometry) in blood, mesenteric lymph nodes, Peyer’s patches, and intestinal epithelium. LI vaccination significantly reduced LI fecal shedding, intestinal colonization, and macroscopic lesions—even under Bhyo co-infection. Vaccinated pigs had earlier and stronger serum IgG and IFN-γ responses. B cells seem to play an important role in the local immune response, and T regulatory cells apparently do not have a significant role in immunomodulation. This study contributes to a better understanding of LI immune response and can provide subtract for further research in the control of LI. Full article

SARS-CoV-2, the causative agent of COVID-19, has led to over seven million deaths worldwide prior to May 2025. Despite widespread vaccination programs, COVID-19 remains a persistent global health challenge, underscoring the urgent need for new therapeutic approaches. Orientin is a flavonoid with reported antiviral activity, though its potential against SARS-CoV-2 remains poorly explored. This study aimed to investigate whether Orientin interacts with the viral Spike protein and impacts viral replication. Molecular docking simulations using DockThor were employed to predict the binding affinity between Orientin and the receptor-binding domain (RBD) of the Spike protein. Fluorescence spectroscopy assays were performed to assess direct interactions between Orientin and the trimeric form of the Spike protein. Additionally, cytotoxicity and viral replication assays were carried out in Vero cells to evaluate Orientin’s antiviral effects. Docking results indicated that Orientin likely binds to key RBD residues involved in ACE2 receptor recognition. Spectroscopic analyses showed a decrease in intrinsic tryptophan fluorescence, suggesting direct interaction. Orientin demonstrated no cytotoxicity in Vero cells and exhibited moderate inhibition of viral replication. These findings suggest that Orientin interacts with critical regions of the Spike protein and may act as a moderate in vitro inhibitor of SARS-CoV-2, warranting further investigation into its therapeutic potential. Full article

In southern Brazil, dengue transmission in the state of Paraná has shown a significant increase in the number of cases since the first recorded occurrence in 1995, with more frequent outbreaks in the west, northwest, and north of the state. We evaluated the impact of a campaign of dengue vaccination administered to a fraction of the population in 30 municipalities in the state by conducting a 15-year interrupted time-series ecological study using data obtained from an official Brazilian data register. We modeled dengue incidence using Poisson regression adjusted by covariates (demographic, climate, and epidemiological factors), allowing for specific temporal variation for each site. A reduction of 18.7% in dengue incidence rate was estimated for a vaccination coverage of 100%. Although there was an increase in the crude dengue incidence rate, considering the three-dose coverage achieved in the municipalities, we estimated an 8.2% relative reduction in the incidence rate. This reduction would increase to 17% with a hypothetical coverage of 90%. The campaign was more effective in small municipalities since they had higher vaccination coverage. These findings underscore the significant impact of the vaccination campaign on reducing dengue incidence trends across the targeted municipalities. Full article