Search Results (504)

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

Background: A quadrivalent HPV vaccine (BPV) has been developed to prevent diseases caused by HPV types 6, 11, 16, and 18 for the first time in Iran. The BPV is composed of the papillomavirus major capsid protein L1, which serves as the primary target in the design of the prophylactic HPV vaccines. To enhance immunogenicity, BPV was formulated with an amorphous aluminum hydroxy phosphate sulfate adjuvant. Methods: The immunogenicity and safety of BPV were assessed through analyses of both humoral and cell-mediated immunity, single and repeated doses, and reproductive effects using animal models. Results: Acute toxicity assessments showed no abnormalities in ophthalmic examinations, biochemical profiles, hematological parameters, and gross pathology findings. Additionally, no mortality or abnormal clinical signs were observed during a 90-day repeated-dose toxicity study. While some inflammatory reactions were noted at the injection sites and in the liver tissues of BPV-treated groups, these reactions were resolved by day 90 after the initial BPV administration. Furthermore, no signs of toxicity were detected in F1 offspring, and no adverse effects were identified in maternal reproductive performance, fertility, or hematological or biochemical parameters throughout the study duration. The BPV candidate successfully induced T-cell proliferation and increased the proportions of CD₃⁺ CD₄⁺ and CD₃⁺ CD₈⁺ T cells. It also stimulated the secretion of both interferon gamma (IFN-γ) and interleukin-4 (IL-4) cytokines in splenocytes isolated from animal models after the third dose. Moreover, anti-HPV L1 IgG antibody production was confirmed on day 14 after administration of each of the three BPV vaccine doses. Conclusions: The findings suggest that BPV is a vaccine candidate that stimulates both cellular and humoral immunity and demonstrate its safety profile in animal models. Full article

Background: Pertussis, diphtheria, tetanus, poliomyelitis, and Haemophilus influenzae type b (Hib) infections pose severe threats to children’s health globally. This study evaluated the safety and immunogenicity of a novel Sabin strain-based adsorbed pentavalent vaccine (DTacP-sIPV/Hib), which offers potential advantages in biosafety and cost-effectiveness compared to wild-type poliovirus-based vaccines. Methods: A repeated-dose toxicity study was conducted in 190 Sprague-Dawley rats, randomly divided into negative control, adjuvant control, low-dose, and high-dose groups. Animals received five intramuscular injections at 21-day intervals, followed by a 56-day recovery period. Parameters assessed included local reactions, body temperature, hematology, serum biochemistry, coagulation, histopathology, T-cell subsets, cytokine levels, and antigen-specific immunogenicity. Results: The primary adverse reaction was dose-dependent local muscle swelling, which was fully reversible within 3–21 days. Only transient body temperature fluctuations and adjuvant-related hematological/biochemical abnormalities were observed, all resolving after the recovery period. No vaccine-related damage occurred in hepatic/renal function or immune organs. Immunogenicity data showed 100% seroconversion for all bacterial components 21 days after the first dose. The high-dose group achieved 100% seropositivity for all poliovirus serotypes after the second dose, while the low-dose group reached the same after the third dose, with no significant difference in antibody levels between dose groups. Conclusions: The DTacP-sIPV/Hib vaccine exhibits a favorable safety profile and robust immunogenicity in rats, supporting its further clinical development. The use of Sabin strains reduces biosafety risks and manufacturing costs, making this vaccine a promising candidate for immunization programs, especially in resource-limited regions. Full article

Background: With the emergence of SARS-CoV-2 Omicron sub-variants exhibiting increased transmissibility and immune escape, booster immunization is recommended. Ideally, vaccination across all age groups, including children and adolescents, is critical to control viral spread and reduce variant emergence. The heterologous scheme consisting of two doses of SOBERANA^® 02 followed by a third dose of SOBERANA^® Plus, which are recombinant protein subunit vaccines constructed from the ancestral RBD, has proven safety, immunogenicity, and effectiveness in pediatric populations as primary series. This study evaluated the safety and immunogenicity of a SOBERANA^® Plus booster dose administered six months after primary vaccination in individuals aged 3–18 years. Methods: In this follow-up analysis of a phase I/II trial, 244 participants received the booster. Safety was monitored via active surveillance at 1 h, 24 h, and over 28 days post-vaccination. Humoral responses were assessed 28 days post-booster. Antibody responses to the SARS-CoV-2 nucleocapsid (N) protein were assessed in all collected serum samples. Results: Adverse events occurred in 18% of participants, predominantly local (85.2%) versus systemic (14.8%); no serious or severe adverse events were reported. All humoral response parameters increased significantly post-booster, including neutralizing antibodies against D614G (24.7-fold increase) and Omicron BA.1 (55.9-fold increase), with similar responses in N-negative and N-positive individuals. Importantly, cross-neutralizing activity against recent Omicron sub-variants (XBB.1.5 and EG.5.1) was also detected. Conclusions: A SOBERANA^® Plus booster is safe and significantly enhances cross-neutralizing immunity against evolving Omicron sub-variants in children and adolescents. These results highlight the potential of first-generation RBD-based vaccines to maintain broad immunity despite viral evolution. Full article

Background/Objectives: As of April 2025, La Réunion is facing a second major chikungunya virus (CHIKV) outbreak, following the 2005–2006 epidemic that infected nearly one-third of the population. IXCHIQ^®, a live-attenuated, single-dose vaccine, offers an opportunity for targeted immunization to complement vector control efforts. Using surveillance data up to 23 February 2025 (week 7), we estimated the potential scale of the 2024–2025 chikungunya outbreak in La Réunion and how much of the burden could have been averted by an emergency vaccination campaign at different detection thresholds. Methods: A stochastic SEIR–SEI host–vector model was calibrated to weekly case counts (weeks 46/2024–7/2025). We projected the epidemic under three vaccination-trigger scenarios (≥100, ≥3000, ≥40,000 detected cases) and two incremental vector-control assumptions (10% and 20% reductions in biting rate). Several mosquito-related parameters—extrinsic incubation period, offspring number, and mortality rate—were temperature-dependent, based on daily temperatures in La Réunion. Vaccination was applied homogeneously, using a 14.5% coverage to reflect the proportion of the population targeted in the initial public health recommendation. Results: Our findings indicate that without vaccination, up to 27.5% of the population could become infected. If vaccination would begin after 100 detected cases, 75% of infections could be prevented. Delaying until 3000 or 40,000 cases reduced effectiveness to 41% and 11%, respectively. Conclusions: Our results show that timely emergency vaccination can substantially reduce outbreak size. This underscores the importance of preparedness and rapid response by public health authorities in high-risk regions. Full article

Human mpox, caused by the mpox virus, is a reemerging viral zoonosis that has gained global attention due to recent Clade IIb outbreaks outside of Africa, as well as ongoing Clade Ia and Ib outbreaks in the Democratic Republic of Congo (DRC) and surrounding regions. Since the start of these outbreaks in 2022, approximately 160,000 people have been affected across more than 100 countries. People with human immunodeficiency virus (HIV; hereafter referred to as PWH) have been disproportionately affected, accounting for approximately 50% of all cases. Mpox is typically a self-limiting illness causing smallpox-like symptoms lasting 2–4 weeks, which can cause significant pain and morbidity. People with uncontrolled or advanced HIV face an elevated risk of severe mpox, secondary complications, and worse outcomes. Vaccination with second- and third-generation vaccinia-based smallpox vaccines has emerged as an important tool in mpox prevention, alongside behavioural modification to mitigate risk. However, only the third-generation, live-attenuated, non-replicating vaccine, modified vaccinia Ankara (MVA-BN [Bavarian Nordic]), is approved for use in PWH. Real-world estimates suggest that two doses of MVA-BN administered as pre-exposure prophylaxis confers vaccine effectiveness in the range of 66–90%. Additionally, MVA-BN has been widely demonstrated to have an acceptable safety profile. This narrative review explores the changing epidemiology, clinical manifestations, and outcomes of mpox in PWH. We also summarise evidence from the Clade IIb outbreaks on the effectiveness and safety of MVA-BN among PWH. Despite progress in our understanding, knowledge gaps persist regarding vaccine performance in individuals with advanced immunosuppression. Furthermore, due to the emergent nature of outbreaks in the DRC and surrounding areas, limited information is available regarding implications for PWH in the context of Clade Ia and Ib. We aim to provide healthcare providers, community stakeholders, and researchers with a foundational understanding of mpox in PWH and the role of MVA-BN in mpox prevention among this group, while highlighting areas of uncertainty. These insights may be helpful in the planning of future research and to inform strategies for the prevention and management of mpox among PWH, particularly those with advanced or uncontrolled HIV. Full article

Background: Numerous studies have proved the efficacy of vaccination in reducing Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission and the coronavirus disease (COVID-19) burden. However, even though the COVID-19 vaccination coverage is high for primary doses, a booster dose is needed to sustain protection. Continuing our previous research, this study evaluates the immunogenicity and safety of full and half doses of two COVID-19 booster vaccines, ChAdOx1-S (AstraZeneca) and BNT162b2 (Pfizer-BioNTech), in individuals primed with ChAdOx1-S. Methods: This study was an observer-blind randomized controlled trial to evaluate the immunogenicity and safety of half and full doses of two COVID-19 booster vaccine types, BNT162b2 and ChAdOx1-S, among fully vaccinated, ChAdOx1-S-primed individuals in Jakarta, Indonesia. A total of 329 participants were randomized to receive either full or half doses of the booster vaccines, namely the ChAdOx1-S and BNT162b2 COVID-19 vaccines. Immunogenicity was assessed through SARS-CoV-2 antibody titers and neutralizing antibodies (NAbs) at 28 days post-booster, while safety was monitored via adverse event reporting. Results: The results showed that both vaccines demonstrated increased geometric mean titers (GMTs) post-booster. In the ChAdOx1-S booster group, at the baseline visit (day 0) and third visit (day 28), no statistically significant differences in GMT between the half- and full-dose groups were observed (p = 0.970 and 0.539, respectively). In the BNT162b2 group, no statistically significant difference was noted at the baseline visit, while the full dose was higher than the half dose at 28 days (Day 28, p = 0.011). Surrogate virus neutralization tests (sVNTs) and NAbs assays also revealed no significant differences between the half and full dose groups for both the Wuhan strain and the Delta variant. The BNT162b2 group compared to the ChAdOx1-S group revealed a statistically significant increase in IgG levels compared to ChAdOx1-S, with p-values of <0.001 and <0.001 for the half dose and full dose, respectively. This was also reflected in the NAbs test results, where BNT162b2 showed significantly higher levels against both the Wuhan strain and Delta variant. Adverse events were predominantly mild: 79.6% (n = 86/108) in the ChAdOx1-S full-dose group, 75.4% (n = 43/57) in the ChAdOx1-S half-dose group, 84.2% (n = 101/120) in the BNT162b2 full-dose group, and 92.6% (n = 88/95) in the BNT162b2 half-dose group, with pain at the injection site being the most common local reaction and myalgia and headache the most frequent systemic reactions. One serious adverse event was reported, assessed as unrelated to the vaccine. Conclusions: This study confirms that half doses of ChAdOx1-S and BNT162b2 are as immunogenic and safe as full doses, and a heterologous booster is more immunogenic than a homologous booster. Full article

Standardized, one-size-fits-all COVID-19 booster schedules may be suboptimal due to individual variation in immune backgrounds, particularly prior infection, which induces robust hybrid immunity. This study estimated optimal booster timing by modeling antibody decay in relation to surrogate correlates of protection (CoP). In a prospective cohort of 177 Japanese healthcare workers, we longitudinally monitored anti-spike receptor-binding domain (S-RBD) antibody titers following BNT162b2 vaccination. Participants were stratified into SARS-CoV-2-naïve and previously infected groups. Mixed-effects models were developed to predict when antibody titers would decline below predefined CoP thresholds. The model estimated optimal booster timing after a two-dose primary series to be 3–5 months for naïve individuals and approximately one year for those with prior infection. Following a third dose, the estimated interval extended to 8–12 months for the naïve group and 1.5–2 years for the previously infected group. These substantial differences underscore the limitations of uniform booster schedules. Our findings provide a quantitative framework for personalized vaccination strategies based on individual antibody profiles and immune status, thereby optimizing protection. Full article

Background: Despite remarkable progress in expanding access to childhood vaccines in the last two decades, global coverage with the third dose of the diphtheria–tetanus–pertussis-containing vaccine (DTP3) has recently plateaued, with many countries yet to meet the targets of the Immunization Agenda 2030 (IA2030). As countries cluster around the 80% coverage mark, further gains require targeted interventions for unreached populations. This analysis disaggregates children missing DTP3 into three groups—zero dose (ZD), missed DTP (MD), and drop-out (DO)—which, with DTP3, form four mutually exclusive groups, and examines which of these groups contributes most to coverage changes across countries. Methods: A total of 295 Demographic and Health Surveys from 1986 to 2023 were analyzed across 80 countries, comprising over 2.4 million children. Children were classified into mutually exclusive groups: DTP3, ZD, MD, and DO. We described trends over time and conducted decomposition analyses using a naïve approach and a structural model with isometric log-ratio transformations and causal mediation pathways. Results: Among the 2.4 million children across 80 countries, 63.8% had received DTP3, while 16.2% were DO, 8.8% were MD, and 11.2% were ZD. Countries showed important variations: some mainly reduced ZD, others reduced MD or DO, many achieved balanced progress, and a few experienced setbacks. The naïve model showed that coverage changes reflected different combinations of shifts across ZD, MD, and DO depending on context. The structural model indicated that DO had the strongest direct association with DTP3 coverage, followed by MD and ZD. Conclusions: This analysis highlights the differential contribution of intermediate groups to coverage variations over time. Understanding the association between coverage gains and shifts in ZD, MD, or DO can complement existing strategies to inform targeted planning and accelerate progress towards IA2030 equity goals. Full article

Background: Dose-sparing approaches can be effective in maintaining immunogenicity and safety while expanding vaccine coverage. We previously demonstrated that a half dose of ChAdOx1 nCoV-19 is as effective and immunogenic for primary vaccination. Methods: This non-inferiority, non-randomized controlled trial evaluated the effectiveness, humoral, and cellular immune responses of a third booster dose—comparing half-dose and full-dose regimens—in individuals aged 18–49 years, with a 1-year follow-up. Results: A total of 2801 participants were enrolled: 2352 received half doses and 449 received full doses. The incidence rate of COVID-19 was 225.0 per 1000 person-years in the half-dose group and 173.8 in the full-dose group, with no significant difference in effectiveness (β = −0.05; 95% CrI: −0.24 to 0.15). No deaths occurred, and hospitalization rates were similar. In a subsample (n = 558), anti-S IgG levels peaked 28 days post-dose and declined by day 180 after the primary series [175 (121–252) vs. 121 (71–208) GMT, p < 0.001], but remained elevated after the booster [192.1 (124–297) vs. 550 (380–797) GMT, p < 0.001]. Booster antibody levels were similar between groups [592.4 (318–1140) vs. 550 (380–797) GMT]. The half-dose group showed high titers against Omicron and robust T/B-cell responses (e.g., EMCD4, EMCD8, IFN⁺CD4⁺, CD19⁺TNF⁺). Conclusions: Fractional half dose of ChAdOx nCov-19 was effective and non-inferior to a full booster dose. Homologous regimen with 3 half doses or 3 full doses induced a similar increase in antibody titers and robust cellular response. ClinicalTrials.gov (NCT05059106). Full article

Background/Objectives: The COVID-19 vaccines have been extensively studied for their potential adverse side effects. However, reports of unexpected but potentially beneficial immune responses have received comparatively less attention. Methods: In this case series, a PubMed search was conducted using the terms “warts”, “verruca”, “HPV”, “COVID-19”, “SARS-CoV-2”, “immunization”, and “vaccination.” All reported cases of wart clearance temporally linked to COVID-19 vaccination were identified and summarized, including patient demographics, vaccine type, number of doses, timing of clearance, and follow-up duration. Results: Five cases were identified. Patients varied in age, sex, comorbidity, and immunologic status. Warts were long-standing and treatment-resistant in all cases. Clearance occurred within approximately 2–4 weeks following the second or third vaccine dose (either mRNA-based [BNT162b2, mRNA-1273] or adenoviral vector [ChAdOx1-S]) and was sustained for 2–8 months of follow-up with no recurrences reported. Conclusions: While causality cannot be determined, the convergence of reports across diverse patients, consistent timing of clearance, and plausible immunologic pathways suggest that COVID-19 vaccination may, in rare instances, trigger beneficial immune activation against HPV-infected keratinocytes. Recognition of such unexpected outcomes underscores the need for broader vaccine safety and efficacy surveillance that includes both adverse and beneficial immune effects. Full article

Background: Streptococcus equi subspecies equi (S. equi) is the cause of strangles, one of the most prevalent diseases of horses worldwide. The disease is characterised by fever and the formation of abscesses in the lymph nodes of the head and neck, which can restrict the airway. A multicomponent subunit vaccine, Strangvac, has been shown to effectively reduce clinical signs of strangles and to reduce its incidence. Objective: The aim of this study was to determine the immune response against the immunoglobulin-cleaving endopeptidase IdeE, a key protective component within the vaccine and the ability of antibodies to neutralize the proteolytic activity of IdeE. Methods: An in vitro assay was developed to measure the functional inhibition of recombinant IdeE by horse sera pre- and post-vaccination. The IdeE-neutralising titres were compared to the corresponding IdeE-specific antibody titres measured by iELISA (indirect Enzyme-Linked Immunosorbent Assay). Results: A significant IdeE-specific antibody response in blood serum collected from ponies was induced after Strangvac vaccinations. Concomitantly, significant increases in the neutralising activity of IdeE occurred, persisting for at least 12 months post-second vaccination. IdeE-neutralising activity was further increased significantly after a third vaccination, even when the third dose was administered 12 months after the second dose, demonstrating that immunological memory to the vaccine persisted for 12 months. There was a significant correlation between the IdeE-neutralising activity of blood sera and the level of IdeE-specific antibodies. Conclusions: These data provide insights into one potential mechanism by which this vaccine protects Equids against or during S. equi infection. Full article

Despite proven effectiveness, human papillomavirus (HPV) vaccination uptake remains suboptimal in many countries. The aim of this study was to explore differences in beliefs about HPV and HPV vaccination, the information environment and social influences shaping vaccination decisions between male and female undergraduate university students in Belgrade, and to identify sex-specific factors associated with HPV vaccine uptake. A cross-sectional study was conducted between April and December 2024. An online questionnaire was completed by 1529 female and 423 male students who were either receiving their second or third dose of the nonavalent HPV vaccine, or accessing general healthcare services at the general medicine department of the Institute for Students’ Health of Belgrade. Hierarchical logistic regression was used to identify predictors of HPV vaccine uptake in male and female students. Among female students, HPV vaccine uptake was associated with stronger beliefs in vaccine efficacy (OR = 2.01, 95% CI: 1.50–2.69) and safety (OR = 2.29, 95% CI: 1.69–3.10), lower perceived lack of information (OR = 0.71, 95% CI: 0.60–0.84), and social influence of family members, (OR = 1.45, 95% CI: 1.04–2.03), colleagues (OR = 1.62, 95% CI: 1.01–2.59) and media (OR = 1.92, CI: 1.10–3.37). Among male students, vaccine uptake was associated with stronger beliefs in vaccine efficacy (OR = 2.14, 95% CI: 1.37–3.34), lower perceived lack of information (OR = 0.71, 95% CI: 0.52–0.98), more frequent reliance on scientific literature (OR = 1.50, 95% CI: 1.15–1.97) and family (OR = 1.37, 95% CI: 1.07–1.75) and less frequent use of YouTube (OR = 0.70, CI: 0.53–0.92) as sources of information, and social influence of family (OR = 1.83, 95% CI: 1.03–3.24). This study highlights significant sex differences in factors influencing HPV vaccine uptake, indicating that tailored approach is required in designing vaccine promotion strategies. Strengthening communication on efficacy and safety, improving access to reliable information, and addressing sex-specific concerns such as safety and financial barriers in females and misinformation in males could improve uptake and equitable HPV protection. Full article

Background/Objectives: Group B Streptococcus (GBS) is a significant cause of perinatal infection in neonates and infants. Complications could include neonatal sepsis and meningitis, preterm birth, stillbirth, or death. Though no GBS vaccine is currently licensed, maternal immunization is expected to be a highly effective strategy to address invasive GBS disease—particularly in low- and middle-income countries (LMICs), where the disease burden is the greatest and access to existing interventions is limited. In this study, we present a novel hexavalent GBS vaccine candidate with a unique combination of serotypes (ST)—Ia, Ib, II, III, V, and VII—that could be an efficacious and cost-effective intervention, with the broadest coverage of 99% against circulating serotypes globally. Methods: The 6-valent conjugate vaccine candidate, GBS-06, is developed using a novel approach by linking the six polysaccharides (PS) to recombinant cross-reactive material 197 (rCRM197) carrier protein derivatized with a hydrazide-polyethylene glycol-hydrazide (HZ-PEG-HZ) linker. A repeat-dose GLP toxicology study with GBS-06 was conducted at the highest clinical dose of 20 µg in rabbits with saline as the placebo control. Results: The results reveal induction of robust anti-capsular polysaccharide-specific IgG responses against each of the six serotypes after each dose with the highest antibody GMCs at Day 49 following the third dose. Conclusions: Hence, this work is the first demonstration of strong immunogenicity achieved using a linker (HZ-PEG-HZ) for GBS glycoconjugate vaccine development. The positive data from the study have strong implications in the advancement of the candidate for evaluation in clinical trials and provide a licensure pathway for maternal immunization. Full article

Background: COVID-19 vaccination and subsequent booster doses became critical components of public health strategies to control the pandemic and reduce disease severity, especially in fragile individuals. Among these, subjects undergoing dialysis represent one of the highly vulnerable populations. Methods: We conducted a multicenter case–control study among dialysis patients between March 2021 and May 2022 (study population n = 3264). We evaluated anti-S/RBD-IgG and anti-SARS-CoV-2 neutralizing antibodies before (T3) and after (T4) the third dose in individuals with a COVID-19 diagnosis after the third dose (cases) and in those who did not report infection (controls). Results: The study included 187 cases and 150 controls. Serological analysis showed a significant increase (p < 0.001) in anti-SARS-CoV-2 antibody levels after the third vaccine dose (from T3 to T4) in both groups. At T3, with the same number of days between the second dose and T3, the antibody levels detected were significantly lower in cases as compared to controls. At T4, we observed similar antibody titers in the two groups. Notably, the mean difference in time from the third dose to T4 was significantly greater in controls (73.0 days vs. 36.7, p < 0.001), suggesting a reduced antibody waning in controls. Accordingly, multivariate analysis showed that the risk of infection was considerably reduced by the pre-third-dose antibody levels. Conclusions: This study reinforces the critical role of the humoral response in preventing infections in the vulnerable population of dialysis patients. Regular monitoring of antibody levels and timely administration of booster doses are essential to optimize protection in this group. Full article