Search Results (121)

Background: During the COVID-19 pandemic, reductions in cases of bacterial diseases transmitted via the respiratory route were reported by the Invasive Respiratory Infection Surveillance Consortium. Here, we evaluate the epidemiology of invasive meningococcal disease (IMD) in Argentina, Brazil, Chile, and Colombia during and after the COVID-19 pandemic. Methods: The epidemiology of meningococcal disease was reviewed in selected South American countries through 2023 from publicly available national surveillance system databases. Results: The incidence of IMD decreased substantially in 2020 in Argentina, Brazil, Chile, and Colombia and was followed by a trend of increased disease. Similarly to observations in several European countries, the post-pandemic rebounds in cases of IMD in the four South American countries included in this analysis were mainly caused by serogroup B, that became one of the predominant serogroups causing IMD in all four countries. Conclusions: Enhanced surveillance of IMD, including genomic characterization of strains, is needed to inform public health policymakers and guide future vaccination strategies in the region. Full article

Background/Objectives: This study aimed to evaluate the immunogenicity and safety of a Meningococcal A and C Polysaccharide Conjugate Vaccine in 3–5-month-old infants. A single-center, randomized, blinded, positive-controlled phase III clinical trial was conducted in Binyang County, Guangxi Zhuang Autonomous Region, China. Infants aged 3–5 months were randomly assigned to the experimental or control group at a 1:1 ratio. Both groups received 3 primary doses with a 1-month interval between each dose, and a booster dose administered at 18 months of age. Seroconversion rate, seropositivity rate, and GMT of bactericidal antibodies against Neisseria meningitidis groups A and C were assessed, along with adverse reactions within the full course of primary immunization and 30 days after booster immunization. Results: After primary immunization, in the experimental group’s pre-vaccination antibody-negative infants, seroconversion rates for groups A and C exceeded 90%, with antibody fold increases over 90 times; its seroconversion rates and GMT were non-inferior to the control group. Before the 18-month booster, the experimental group’s group A and C antibody seropositivity rates dropped to approximately 70% and 30% (slightly higher than the control), respectively. After booster immunization, the antibody levels against groups A and C were significantly higher than those before the booster and the positive rates and GMT levels of the two groups were similar. Adverse reactions were mainly solicited systemic ones (fever most common), with no statistical difference between groups. Conclusions: The experimental vaccine shows great immunogenicity and safety in infants aged 3–5 months and is non-inferior to the control vaccine. In the booster immunization phase of the control group, sequential vaccination with vaccines from different manufacturers was adopted, and the immunogenicity was good. Full article

The increase in the incidence and antibiotic-resistant strains show a need for a broadly protective vaccine to prevent gonorrhea. OMVax has developed a combination vaccine based on native outer membrane vesicles (NOMVs) from two Neisseria meningitidis (Nm) and two Neisseria gonorrhoeae (Ng) strains. The strains had the acyl transferase LpxL1 knocked out to increase safety, and the reduction-modifiable protein was also knocked out in the Ng strains. Factor H binding protein (FHbp) mutants with reduced Factor H (FH) binding from Subfamilies A and B, respectively, were overexpressed in the Nm strains. The Ng strains individually expressed porin outer membrane protein B 1a (PorB.1a) or PorB.1b. Antibodies elicited by the Nm-Ng NOMV vaccine had SBA with a human complement against diverse Nm and Ng strains grown in the presence of Cytidine-5′-monophospho-N-acetylneuraminic acid (CMP-NANA), had no significant reduction in serum bactericidal activity (SBA) compared to the respective individual vaccines, inhibited the adhesion to human cervical and vaginal cells in five out of six Ng strains tested, and inhibited Nm and Ng colonization in a transgenic mouse model. In conclusion, the Nm-Ng NOMV vaccine has the potential to protect against disease and inhibit colonization by diverse Nm and Ng strains, which may be an advantage for controlling the disease through vaccination, particularly in the adolescent/young adult age group. Full article

Background: Meningococcal B (MenB) vaccination offers protection against invasive meningococcal disease and moderate cross-protection against gonorrhea. However, little is known about coverage and behavioral correlates among men who have sex with men (MSM) in China. This study assessed self-reported MenB vaccination uptake and its associations with sociodemographic and behavioral factors. Methods: We conducted a nationwide cross-sectional survey among 1022 MSM recruited via community-based organizations and online platforms. Vaccination status and recent sexual behaviors were self-reported. Logistic regression identified correlates of uptake, and latent class analysis (LCA) examined behavioral profiles. Results: Participants had a mean age of 29.6 years; most were unmarried (87.7%) and nearly 90% had a college degree or above. Overall, 21.7% reported receiving MenB vaccination. Uptake was positively associated with condomless anal intercourse (aOR = 1.57, 95% CI: 1.08–2.31), group sex (occasionally: aOR = 1.63, 95% CI: 1.01–2.64; frequently: aOR = 3.86, 95% CI: 1.85–8.04), and female partners in the past six months (aOR = 3.69, 95% CI: 2.25–6.10). MSM with multiple casual male partners were less likely to be vaccinated (aOR = 0.55, 95% CI: 0.32–0.93). LCA identified heterogeneous subgroups; notably, the “multi-partner and proactive” group, with high pre-exposure prophylaxis against HIV infection awareness and frequent STI testing, showed low uptake (13.4%). Conclusions: MenB vaccination coverage among MSM in China remained suboptimal. Uptake differed across behavioral subgroups, underscoring the need for stratified, context-specific strategies to inform future vaccine introduction. Full article

Background: Invasive meningococcal disease (IMD) is an uncommon but potentially life-threatening condition, resulting in life-long sequelae or death in up to 20% of cases. Most IMD cases are caused by Neisseria meningitidis serogroups (Men) A, B, C, W, X, and Y. The highest IMD incidence is among children < 5 years of age (YOA). We reviewed IMD epidemiology data and existing national immunization programs (NIP) in the Americas and identify unmet needs to decrease IMD burden in young children. Methods: Using national surveillance data and published literature from 2006 to 2024, we evaluated the IMD burden and national vaccination strategies for children < 5 YOA in the Americas, focusing on Canada, the United States, Brazil, Chile, Argentina. Results: The highest IMD incidence was among infants, followed by children 1–4 YOA, with MenB infections predominating in both age groups. Chile has both MenACWY (2014) and MenB (2023) infant vaccination in its NIP. Argentina and Brazil’s NIPs include MenACWY (2017) and MenC (2010) vaccinations for infants, respectively. In Canada, MenC (2002) vaccination is recommended at 1 YOA (replaced by MenACWY in 2024 in Manitoba); MenB vaccination is selectively recommended. In each country, the incidence of IMD caused by vaccine-preventable serogroups decreased following the introduction of the respective meningococcal vaccination in the NIP. Conclusions: Comprehensive meningococcal vaccination programs in the Americas have the potential to reduce the IMD burden in children < 5 YOA. National recommendations and NIPs could reduce IMD burden by offering equitable access to protection against IMD, aligning with the WHO roadmap to defeat meningitis by 2030. Full article

Background/Objectives: Meningococcal disease (MD) remains a significant public health concern worldwide. In Serbia, mandatory immunization against MD with the meningococcal polysaccharide vaccine (MenAC) for high-risk groups and international travelers was introduced in 2006. Since 2017, the polysaccharide vaccine has been replaced with the quadrivalent meningococcal conjugate vaccine (MenACWY). The aim of this study was to analyze long-term trends in incidence, age-specific patterns, seasonality, and lethality of invasive meningococcal disease (IMD) in the Autonomous Province of Vojvodina (AP Vojvodina), Serbia, over a 28-year period. Methods: A descriptive study analyzed all reported cases of IMD in AP Vojvodina, from 1997 to 2024. Data were obtained from the regional communicable disease surveillance system, based on mandatory hospital reporting and case classification according to national and WHO guidelines. Temporal, demographic, and clinical characteristics, along with disease outcomes, were analyzed. Results: From 1997 to 2024, 175 IMD cases were reported in AP Vojvodina. The annual incidence peaked in 1997 (1.24/100,000), with smaller surges in 2003 and 2005. Since 2006, coinciding with the introduction of immunization against MD, a sustained decline has been observed, with incidence rarely exceeding 0.30/100,000. A slight resurgence occurred in 2023–2024, with 13 cases reported. From 1997 to 2024, IMD in AP Vojvodina exhibited a clear seasonal pattern, with most cases occurring in winter and early spring, peaking in January (17%), March (12%), and February (11%), and the fewest cases occuring in the summer months. Throughout the study period, the highest IMD incidence rates were consistently observed among infants <1 year of age and children aged 1–4 years, with peaks of up to 22.9/100,000 and 16.0/100,000, respectively. Incidence was much lower in older age groups, especially adults. After a 2006 peak, rates declined across all ages, with a slight resurgence in 2023–2024 among children and adolescents. Children aged 1–4 years made up the largest share of IMD cases, peaking in January–March (45.1%). Half of the infant cases were recorded in October–November, while cases in older children, adolescents, and adults were fewer and showed varied monthly patterns, with small peaks in winter and early spring. During the 28-year study period, the highest IMD mortality rate was observed among infants <1 year of age (0.59 per 100,000 population), followed by children aged 1–4 years (0.32 per 100,000). Mortality rates declined progressively with increasing age, with the lowest rate recorded among individuals aged ≥40 years (0.01 per 100,000). Of the 175 IMD cases reported in AP Vojvodina (1997–2024), 21 were fatal (case fatality rate [CFR] = 12.0%). The CFR of IMD varied across age groups. The highest CFR was observed among individuals aged ≥40 years (21.4%), followed by the 5–9 years (17.4%) and <1 year (16.7%) age groups. None of the patients had been vaccinated against MD. Fatal outcomes were more common in children aged 1–4 years and among rural residents, though differences were not statistically significant (p > 0.05). Most deaths (57.1%) occurred in the first quarter of the year. A strong association was found between clinical form and outcome, with meningococcal sepsis being significantly more frequently associated with fatality than meningitis (p = 0.0002). Deaths were sporadic over time, with most occurring within 1–2 days of notification. All confirmed fatal cases were due to serogroup B. Conclusions: MD remains a rare yet serious public health threat in AP Vojvodina. Mortality rates indicate that the public health impact of this disease is greatest among the youngest age groups; however, the risk of death, i.e., disease severity, does not appear to be age dependent. The recent rise in cases, high fatality among sepsis patients, and absence of prior vaccination among all IMD cases highlight the need for enhanced surveillance, physician education, and consideration of introducing both MenACWY and MenB vaccines for high-risk groups. Full article

Meningococcal meningitis is a deadly acute bacterial infection caused by the Neisseria meningitidis bacterium that affects the membrane covering the brain and spinal cord. The World Health Organization launched the “Defeating bacterial meningitis by 2030” initiative in 2018, which relies on recent discoveries of cheap and effective vaccines. Here, we consider one important factor—human behavior—which is often neglected by immunization campaigns. We constructed a game-theoretic model of meningitis in the meningitis belt, where individuals make selfish rational decisions whether to vaccinate based on the assumed costs and the vaccination decisions of the entire population. We identified conditions when individuals should vaccinate, and we found the optimal (equilibrium) population vaccination rate. We conclude that voluntary compliance significantly reduces the endemic levels of meningitis if the cost of vaccination relative to the cost of the disease is sufficiently low, but it does not eliminate the disease. We also performed uncertainty and sensitivity analysis on our model. Full article

Background: While efforts have been made to control meningococcal disease or carriage during mass gatherings (MGs), it is still a significant problem. This meta-analysis aims to assess the prevalence and predictors of meningitis carriage during MGs and travel. Methodology: PubMed, Scopus, Embase, and Cochrane were searched from their conception to January 2025. Cohort and cross-sectional studies assessing the prevalence of meningitis carriage and its serotype related to MGs and/or travel, and risk factors associated with its spread, were considered. The Newcastle–Ottawa scale was used for the quality assessment of studies. Results: Out of 1301 studies, 25 were considered for this meta-analysis. The largest geographic area involved was Saudi Arabia. A meta-analysis of 24 studies identified a pooled prevalence rate of meningococcal disease or carriage of 15.9% (95%CI: 4.45–27.4%) and the most frequent infecting organisms to be Serotype C (13.9%; 95%CI: −14.7 to 42.5; 4 studies) and A (11.5%; 95%CI: −2.13 to 25.2; 9 studies) among those at MGs or traveling. Age, gender, smoking history, and the vaccination status did not affect the infection risk. Conclusions: There is an increased prevalence of meningococcal disease and carriage, especially Serogroups A and C, associated with MGs and travel. New interventions and methodologies should be undertaken to control and prevent meningococcal disease or carriage transmission during such events. Full article

In the United States, adolescents and young adults between the ages of 16 and 23 have high rates of serogroup B meningococcal infections due to an elevated risk for those attending college. This review examines meningococcal vaccination requirements and recommendations for college students in the United States, with a focus on state-level mandates. National stakeholder resources, state legislatures, and official state Department of Health and Department of Education websites were analyzed for each state and Washington, DC. Overall, 26 states mandate MenACWY vaccination for college entry, whereas only 2 have specific requirements for MenB vaccination. Among the six states with the largest state university campus enrollments, half mandate MenACWY vaccination for college students, whereas none mandate MenB. By region, the Northeast had the highest percentage of states with a MenACWY requirement for college entry (77.8%) followed by the South (64.7%), Midwest (41.7%), and West (23.1%). Further research is needed to elucidate the relationship between state mandates and coverage to aid in optimizing meningococcal vaccination for college students. Full article

Background: Neisseria meningitidis B is one of the main causative pathogens of meningitis and other forms of severe meningococcal disease. In the past decade, meningococcal B vaccines have been developed to address this infection and its sequelae. Objective: This article aims to present an example of how the EU regulatory framework allowed the early authorisation of two life-saving vaccines initially based on immunogenicity surrogates of clinical evidence. This was subsequently followed by post-marketing surveillance providing real-world evidence to support their safety profile and impact on the paediatric population in the EU. Methods: We review the evidence supporting the initial regulatory approval of the vaccines, the confirmatory data demonstrating vaccine effectiveness post-authorisation, and the real-world impact of these vaccines on the paediatric population. Results: Two vaccines were approved in the EU for active immunisation to prevent IMD caused by MenB (4CMenB in 2013 and MenB-fHBP in 2017). Both marketing authorisations were based on immunogenicity data (efficacy studies were not feasible due to the rarity of the disease) and safety data generated from pre-authorisation studies. Additional pharmacovigilance activities to further investigate the safety profile and effectiveness studies were requested to be conducted after approval. Both the effectiveness and safety profile of the vaccines were confirmed by these data. Conclusions: This paper illustrates that the EU medicines regulatory framework and safety monitoring system are robust. By supplementing the initial evidence with post-authorisation studies, further effectiveness and safety data enabled regulators to confirm the positive benefit–risk of the vaccines without delaying their access to the people who need them. Full article

Background: The combined diphtheria–tetanus–acellular pertussis (three-component), Haemophilus influenzae type b (Hib, conjugate), and ACYW135 meningococcal (conjugate) vaccine (DTaP-Hib-MCV4) offers a promising alternative to single-component vaccines, potentially simplifying immunization schedules and improving vaccination coverage. Methods: We evaluated the safety, immunogenicity, and protective efficacy of DTaP-Hib-MCV4 in animal models. Acute and long-term toxicity studies were conducted in Sprague-Dawley (SD) rats with equal numbers of male and female animals. Immunogenicity was assessed in female NIH mice and SD rats using a three-dose regimen at 14-day intervals. Orbital blood was collected 14 days post-immunization to measure IgG titers against pertussis, diphtheria, tetanus, Hib, and meningococcal antigens. The protective efficacy was determined using potency tests for the pertussis, diphtheria, and tetanus components; passive protection studies for Hib; and serum bactericidal antibody (SBA) titers against A/C/Y/W135 meningococcal serogroups. Results: Acute and repeated-dose toxicity studies in SD rats showed no signs of abnormal toxicity or irritation at either high (three doses/rat) or low (one dose/rat) doses levels. The no-observed-adverse-effect level (NOAEL) for DTaP-Hib-MCV4 was established at three doses/rat after 8 weeks of repeated intramuscular administration and a 4-week recovery period. Specific IgG antibodies against all the vaccine components were detected in animal sera at both one and three doses/rat, with no evidence of immunotoxicity. Following two-dose primary immunization in murine models, the combined vaccine elicited robust antigen-specific antibody responses, with geometric mean titers (GMTs) as follows: 1,280,000 for pertussis toxin (PT); 761,093 for filamentous hemagglutinin (FHA); 1,159,326 for pertactin (PRN); 1,659,955 for diphtheria toxoid (DT); 1,522,185 for tetanus toxoid (TT); 99 for Haemophilus influenzae type b (Hib); and 25,600, 33,199, 8300, and 9051 for serogroups A, C, Y, and W135 of Neisseria meningitidis, respectively. In the rat models, three-dose primary immunization also elicited robust antigen-specific antibody responses. Protection studies demonstrated efficacy against pertussis, tetanus toxin, and diphtheria toxin challenges. In the Hib challenge study, none of the 10 animals given anti-DTaP-Hib-MCV4 antiserum developed bacteremia after the live Hib challenge (vs. 5814/0.1 mL in the negative control, p < 0.001). In addition, the SBA titers against meningococcal serogroups exceeded the protective threshold (≥1:8) in 92.2% of the immunized mice and 100% of the immunized rats. Crucially, the combined vaccine induced potent immune responses and protective efficacy, with antibody levels and protection against each component antigen comparable to or greater than those of the individual components: DTaP, Hib, and MCV4. Conclusions: These findings demonstrate that the DTaP-Hib-MCV4 combined vaccine is both safe and immunogenic, supporting its potential as a viable alternative to individual vaccines. This combined vaccine may streamline immunization programs and enhance vaccination coverage. Full article

Vaccination with ChAdOx1 nCoV-19 is an important countermeasure to fight the COVID-19 pandemic. This vaccine enhances human immunoprotection against SARS-CoV-2 by inducing an immune response against the SARS-CoV-2 S protein. However, the immune-related genes induced by vaccination remain to be identified. This study employs feature ranking algorithms, an incremental feature selection method, and classification algorithms to analyze transcriptomic data from an experimental group vaccinated with the ChAdOx1 nCoV-19 vaccine and a control group vaccinated with the MenACWY meningococcal vaccine. According to different time points, vaccination status, and SARS-CoV-2 infection status, the transcriptomic data was divided into five groups, including a pre-vaccination group, ChAdOx1-onset group, MenACWY-onset group, ChAdOx1-7D group, and MenACWY-7D group. Each group contained samples with 13,383 RNA features and 1662 small RNA features. The results identified key genes that could indicate the efficacy of the ChAdOx1 nCoV-19 vaccine, and a classifier was developed to classify samples into the above groups. Additionally, effective classification rules were established to distinguish between different vaccination statuses. It was found that subjects vaccinated with ChAdOx1 nCoV-19 vaccine and infected with SARS-CoV-2 were characterized by up-regulation of HIST1H3G expression and down-regulation of CASP10 expression. In addition, IGHG1, FOXM1, and CASP10 genes were strongly associated with ChAdOx1 nCoV-19 vaccine efficacy. Compared with previous omics-driven studies, the machine learning algorithms used in this study were able to analyze transcriptome data faster and more comprehensively to identify potential markers associated with vaccine effect and investigate ChAdOx1 nCoV-19 vaccine-induced gene expression changes. These observations contribute to an understanding of the immune protection and inflammatory responses induced by the ChAdOx1 nCoV-19 vaccine during symptomatic episodes and provide a rationale for improving vaccine efficacy. Full article

Background/Objectives: In France, non-pharmaceutical interventions (NPIs) implemented to control COVID-19 led to a significant decline in invasive meningococcal disease (IMD) cases. However, a rebound in cases, particularly for serogroups W and Y, was observed after the gradual lifting of NPIs, raising questions about an “immunity gap” due to reduced circulation of the bacteria. During the study period, vaccination against MenC was mandatory from 2018, and vaccination against MenB has been recommended since 2022. Methods: We conducted a retrospective seroepidemiological study using 166 normal sera collected between 2016 and 2024. Anti-Neisseria meningitidis IgG levels were quantified by ELISA using purified capsular polysaccharides for serogroups B, C, W, Y, and X. Samples were categorized into three periods: pre-NPIs (n = 72), during NPIs (n = 33), and post-NPIs (n = 61). Statistical comparisons were performed using Kruskal–Wallis tests for non-parametric data. Results: Our results show a significant decline in anti-serogroup B IgG antibody levels after the lifting of NPIs (p < 0.0001) in line with reduced circulation. Anti-serogroup C IgG antibody levels increased incrementally (p = 0.0003), particularly in those aged 1–4 years, likely reflecting a catch-up in anti-meningococcal C vaccination coverage. Anti-serogroup W IgG antibody levels remained stable, suggesting sustained circulation, but shifted to young children in the post-NPI period, potentially due to a genotypic shift. Anti-serogroup Y IgG antibody levels transiently increased significantly (p < 0.0001) during the NPI period but then decreased back after their lifting. Anti-serogroup X IgG antibody levels remained stable, consistent with its low prevalence and the absence of targeted vaccination. Full article

Background: Co-administration of vaccines can impact the immune response and safety. We aim to systematically review the current scientific literature and find evidence regarding the immunogenicity and safety of pneumococcal vaccines co-administered with common vaccines that are recommended for travelers, including hepatitis A, hepatitis B, yellow fever, tetanus, diphtheria, and acellular pertussis (Tdap), Japanese encephalitis, rabies, typhoid, or meningococcal (MCV) vaccine in adults (18 years or older). Methods: We followed the PRISMA 2020 guidelines and used the PICOS process to select the keywords. We searched PubMed, Web of Science, Scopus, EMBASE, and Google from 1 January 2000 to 30 June 2024. We included randomized controlled trials, non-randomized controlled trials, observational studies, case series, and case reports in adults, all published in English. Results: Out of 598 articles screened, 6 studies were included in our study. Three studies involved immunocompetent individuals, and three involved immunocompromised individuals. Co-administration of pneumococcal vaccine with Tdap or Hepatitis A in immunocompetent individuals was safe and immunogenic. Similar findings were reported for immunocompromised individuals when pneumococcal vaccines were co-administered with Tdap, hepatitis A, and hepatitis B. However, no reports investigated the co-administration of yellow fever, rabies, Japanese encephalitis, and typhoid. Two non-randomized studies in immunocompromised individuals had a high risk of bias. Conclusions: The studies collectively indicate that the co-administration of pneumococcal vaccines with Hepatitis A and Tdap vaccines in adult immunocompetent and immunocompromised individuals is safe and immunogenic. However, a knowledge gap remains, and further high-quality studies are needed, particularly due to the limited number of studies and the potential risk of bias. Full article

Background: The Spanish Interterritorial Council of the National Health System (a central government body) currently recommends vaccination against meningococcal serogroup C (MenC) at 4 and 12 months of age for prevention of invasive meningococcal disease (IMD). The Advisory Committee on Vaccines of the Spanish Association of Pediatrics (a professional medical association) and numerous Spanish regional bodies instead recommend quadrivalent vaccination against serogroups A, C, W, and Y (MenACWY) at 4 and 12 months of age. The central government and Spanish Association of Pediatrics also recommend MenACWY vaccination at 12 years of age. This study assessed the potential public health effects of replacing the MenC vaccination schedule with different MenACWY vaccination schedules in infants. Methods: Here, a static multi-cohort population model was used to evaluate potential effects on public health of IMD due to meningococcal serogroups C/W/Y, comparing MenC infant vaccination (reference strategy) against four different strategies including quadrivalent tetanus toxoid conjugate vaccine (MenACWY-TT; Nimenrix^®, Pfizer Europe MA EEIG, Brussels, Belgium) infant vaccination; all strategies included MenACWY-TT vaccination at 12 years of age. Results: The most effective strategy for infant vaccination was MenACWY-TT at 2, 4, and 12 months, preventing an estimated additional 103 IMD cases, 17 deaths, and 41 cases with long-term sequelae (LTS) versus the reference strategy in the base-case IMD incidence scenario. When strategies included a two-dose infant schedule, the earlier the infant MenACWY-TT vaccine was administered, the more additional cases, deaths, and cases with LTS were prevented (base-case and high-incidence scenarios). Conclusions: This analysis supports implementation of MenACWY-TT as a replacement for MenC vaccination. Full article