Quadrivalent Vaccine Research Articles

Modeling antibody persistence after MenACYW-TT vaccination and comparative analysis with other quadrivalent meningococcal vaccines

Evaluating the persistence of antibody titers produced by quadrivalent meningococcal vaccines is crucial for determining the optimal timing for primary and booster doses. Using 3 − 7-year persistence data after a single priming dose of MenACYW-TT to fit a statistical model of antibody decay over time (10 years), this analysis modeled long-term antibody persistence for this vaccine in toddlers (12–23 months), adolescents/young adults (13–26 years), and older adults (≥ 56 years), comparing it with other vaccines (MCV4-TT, MenACWY-CRM, MPSV4). The statistical model is based on a Bayesian approach and it accounts for vaccine- and age group-specific antibody decline, missing data, assay errors, and antibody boosting from breakthrough infections. At 10 years post-vaccination, it predicted comparable or higher seroprotective immunopersistence for MenACYW-TT (titers ≥ 1:8 with hSBA) versus (1) MCV4-TT in toddlers (77% [95% CI 70–84] vs. 17% [6–31] for serogroup C, 67% [59–74] vs. 36% [20–53] for serogroup W); (2) MenACWY-CRM in adolescents/young adults (63% [55–71] vs. 40% [32–48] for serogroup C, 67% [59–74] vs. 57% [47–67] for serogroup W); and (3) MPSV4 in older adults (31% [23–39] vs. 22% [14–29] for serogroup C, 38% [31–46] vs. 20% [14–27] for serogroup W). In conclusion, our analysis indicated similar or higher immune persistence at 10 years for MenACYW-TT compared with other quadrivalent meningococcal vaccines, particularly for serogroups C and W.

Incidence of Circulating Antibodies Against Hemagglutinin of Influenza Viruses in Epidemic Season 2023/2024 in Poland

The aim of this study was to determine the level of anti-hemagglutinin antibodies using the hemagglutination inhibition test (HAI) in the blood sera of patients collected during the 2023/2024 epidemic season in Poland. This data is valuable for assessing the level of population immunity to influenza viruses circulating in Poland during this epidemic season. The study material consisted of serum samples collected across the country and divided into seven age groups. The test results confirmed the presence of anti-hemagglutinin antibodies for the antigens included in the quadrivalent influenza vaccine recommended by the World Health Organization (WHO) for the 2023/2024 epidemic season: A/Victoria/4897/2022 (H1N1)pdm09, A/Darwin/9/2021 (H3N2), B/Austria/1359417/2021 (B/Victoria lineage) and B/Phuket/3073/2013 (B/Yamagata lineage). The highest values of the geometric mean (GMT = 121.0 [95% CI: 108.5–134.9]) and protective factor (70 [95% CI: 67–74]%) were recorded for the A/H3N2/influenza virus antigen. In Poland, the vaccination rate of the general population in the discussed season was only 5.52%. The obtained results can therefore be interpreted as a response of the immune system, consisting of the production of anti-hemagglutinin antibodies in patients who had previously had an infection caused by the influenza virus.

Cost-benefit analysis of a quadrivalent influenza vaccine in India

Background In India, influenza presents a significant burden of disease to the population at large. Influenza vaccination is a cost-effective means of preventing the disease, with quadrivalent vaccines providing broader protection against influenza by covering more strains, but generally at a higher list price, than older trivalent vaccines. Research design and methods Broadly, the economic burden of influenza can be categorized into treatment and productivity costs. We undertake a cost-benefit analysis to determine the cost-effectiveness of a quadrivalent influenza vaccine versus no vaccination amongst healthy adults and pregnant women from the perspective of both employers and the Employees’ State Insurance Company (ESIC) in India. Results Administration of the quadrivalent vaccine results in better outcomes in terms of productive days worked and disease infection rates amongst the target populations whilst incurring lower overall health resource utilization costs than when no vaccine is employed. In healthy adults, we estimate a saving of INR 13,730 per case averted from the corporate perspective and a saving of INR 11,211 from the ESIC perspective. Deterministic and probabilistic sensitivity analyses indicate that there is a high probability that these results hold true given the uncertainty in our model’s input parameters. Conclusions We find that for healthy adults and pregnant women, receiving a quadrivalent influenza vaccine is dominant over no vaccination in terms of cost-effectiveness that is, it results in better health outcomes at a lower overall cost.

Influenza-Specific T-Cell Responses to Vaccination Are Independent of Underlying Hematological Malignancy: Analysis of a Randomized Influenza Vaccination Trial.

There are few in-depth immunogenicity analyses of novel influenza vaccination strategies in high-risk patients with hematological malignancy (HM). Participants receiving treatment for active HM (multiple myeloma [MM], chronic lymphocytic leukemia [CLL], or non-Hodgkin lymphoma [NHL]) in a randomized controlled trial of 2 doses of adjuvanted quadrivalent inactivated influenza vaccine (QIV) versus 2 doses of standard-dose QIV during 2022 were included. Hemagglutination (HA) inhibition assay and HA probe-specific B-cells were compared at baseline and 1, 2, and 6 months after the first vaccine dose (visits 1-4). A subset underwent ex vivo live virus infection of peripheral blood mononuclear cells at visits 1 and 3 with A/H1N1 and A/H3N2 to assess interferon (IFN) γ-producing CD4+ T cells, CD8+ T cells, natural killer cells, CD161+TRAV1-2+ mucosal-associated invariant T (MAIT)-like T cells and γδ T cells. In total, 62 patients with HM were analyzed (32 in the adjuvanted-dose and 30 in the standard-dose group), 13 (21.0%) with CLL, 24 (38.7%) MM, and 25 (40.3%) with NHL. Participants with MM had higher geometric mean antibody titers (P < .001) and influenza-specific B-cell responses for H1, H3, and B/Victoria at visits 2 and 3 than those with CLL or NHL (P < .05). The total CD19+ B-cell and HA probe-specific B-cell counts were found to significantly predict seroconversion at visits 2 and 3. Overall, with vaccination, there was an increase in the percentage frequency of B/Victoria influenza-specific B-cells (P = .01), IFN-γ-producing CD4+ T cells (P = .01) for A/H1N1 and IFN-γ-producing MAIT-like cells (P = .003) for A/H3N2. Influenza strain-specific cellular responses were detectable following vaccination despite expected B-cell depletion in patients receiving active treatment for HM. Australian New Zealand Clinical Trials Registry ACTRN12622000454774.

Evaluation of Anti-HPV18 Antibody Titers Preceding an Incident Cervical HPV18/45 Infection

Background: The Human Papillomavirus (HPV) vaccine generates high antibody titers against targeted HPV types. This study investigated vaccine-induced anti-HPV18 immunoglobulin (IgG) antibody titers and subsequent HPV18/45 infections. Methods: We performed a nested matched case-control study leveraging a prospective longitudinal cohort of adolescent and young adult women (AYW) vaccinated with the quadrivalent HPV vaccine (4vHPV) attending the Mount Sinai Adolescent Health Center (MSAHC) in Manhattan, NY. The case individuals included AYW who had an incident detection of cervical HPV18 (n = 3) or HPV45 (n = 34) DNA after vaccination and were compared to two vaccinated control individuals (HPV18/45-negative); one random control (RC, n = 37) and one high-risk control (HRC, n = 37) selected from the upper quartile of a sexual risk behavior score. Serological titers against HPV18 were measured by end-point dilution and enzyme-linked immunosorbent assay (ELISA) in serum collected before the incident detection of HPV. Matching was performed based on age at first dose, follow-up time, and sexual risk behavior score. Conditional logistic regression was used to assess the association between case-control status and anti-HPV antibody titers, consistent with the matched-pair design. Results: Antibody titers for HPV18 were most different between AYW who developed an HPV18/45 infection compared to high-risk controls OR = 1.66, 95% CI: 0.96–2.85 (p = 0.1629). Analyses of pooled data from vaccinated recipients including who developed HPV16/31 or HPV18/45 infections demonstrated that the odds of a one-log unit increase in anti-HPV16 or 18 antibody titers, respectively, were 40% higher in the combined control groups (RC + HRC, n = 160) (OR = 1.40, 95% CI: 1.09–1.79, p = 0.0135) and 73% higher in the HRC (n = 80) (OR 1.73, 95% CI: 1.34, 2.52, p = 0.0117) compared to HPV16/18/31/45 cases (n = 80). Conclusions: Overall, these findings suggest that higher IgG antibodies to HPV16/18 after vaccination represent an increased likelihood of protection from homologous and cross-reactive HPV types (HPV16/18/31/45). These results show that differences in antibody titers are associated with breakthrough infection after vaccination, suggesting that further study of long-term antibody titers and infection should be pursued.

Distribution of Human Papillomavirus Genotypes in Real-World Cervical Self-Collected Scrapings From the Dutch Cervical Cancer Screening Program.

High-risk HPV (hrHPV) is the necessary cause of cervical cancer with HPV16/18 accounting for around 70% of the cases worldwide, while other non-HPV16/18 hrHPV genotypes prevail in ~95% of high-grade lesions. Understanding regional genotype distribution of hrHPV types not covered by the nonavalent vaccine is crucial for evaluating vaccine effectiveness and enhancing population-based screening (PBS). The objective of the present study is to update hrHPV genotype prevalence in a non-vaccinated cohort of 1200 hrHPV-positive women from the Dutch PBS using INNO-LiPA HPV Genotyping Extra-II to identify 32 individual HPV genotypes in self-sampled material. HrHPV prevalence for all 32 genotypes, also grouped by bivalent, quadrivalent, and nonavalent vaccine types (2vHPV, 4vHPV, and 9vHPV), was reported by histologic diagnosis and age. The most common genotypes were HPV16 (394,33%), especially in younger women, followed by HPV31 (216,18%) and HPV52 (199,17%). 2vHPV genotypes were found in 23% (n = 90) of NILM cases, 27% (n = 84) of CIN0/CIN1, 45% (n = 74) of CIN2, 71% (n = 219) of CIN3, and 92% (n = 12) of cervical cancers. In comparison, 9vHPV genotypes appeared in 60% (n = 240) of NILM, 69% (n = 218) of CIN0/CIN1, 88% (n = 145) of CIN2, 94% (n = 289) of CIN3, and all cervical cancers (n = 13). HrHPV types not included in 9vHPV had an overall prevalence of 19% (n = 225), with 88% (197/225) found in NILM or CIN0/CIN1. This study highlights vaccine-type HPV in all cancer cases and many high-grade lesions, reinforcing the need for improved vaccination efforts and broader protection.

HPV Vaccines – An Overview

Abstract Human papilloma viruses (HPVs) are a group of viruses that can infect the stratified epithelium of the skin and mucosa. Based on their oncogenic potential, they can be divided into high risk and low risk types. HPV accounts for 7,30,000 cases of cancers all over the world. In June 2006, the first HPV vaccine – Gardasil – was approved by the FDA. After this in 2007, Cervarix was approved and finally Gardasil 9 in 2014. Currently, there are six prophylactic vaccines against HPV, of which five have been pre-qualified by WHO. The bivalent vaccines offer protection against acquiring HPV 16 and 18, which cause 70% of cervical cancers. The quadrivalent and nonavalent vaccines offer additional protection against low-risk HPV 6 and 11. The currently available vaccines have been found to be safe in both pre- and post-licensure trials. The vaccines offer excellent protection against cervical intra-epithelial neoplasia of grade 2 and 3. The role of HPV vaccines in prevention of other cancers is mostly supported by small retrospective studies. The currently available vaccines are approved for prophylactic use only. There have been attempts to use HPV vaccines therapeutically, and there are conflicting reports regarding their efficacy. This article reviews the currently available vaccines, their indications, adverse effects, contraindications, and epidemiological impact. It also highlights the off label therapeutic uses in various conditions and other potential vaccine candidates.

The situation with vaccination in Shkodra region after the first year of implementation of human papillomavirus vaccine

Human papillomavirus (HPV) is a common sexually transmitted infection with potentially serious health con­sequences, including anogenital and oropharyngeal cancers and genital warts. In 2022, Albania implemented an HPV vaccination program for girls aged 13-20 years, offering a single dose of the bivalent or quadrivalent vaccine. This study aims to evaluate the status of HPV vaccination in the Shkodra region after its first year of implementation and explore reasons for non-vaccination. This retrospective study collected data from official vaccination registers at health centers in the Shkodra region for the period 2022-2023. Additionally, face-to-face interviews were conducted with nurses res­ponsible for administering vaccinations (vaccinators) and with parents present at the centers. Quantitative data were obtained and validated by the Chief Vaccination Office in the Epidemiology Sector at the Local Health Care Unit in Shkodra. A simple descriptive and comparative method was employed. Data for this study were gathered from two main sources: official vaccination records and interviews conducted with nurses and parents. Quantitative data were processed and analyzed using Microsoft Office Excel 2010. The vaccination coverage plan aimed to vaccinate 812 girls, with 67% (n=546) from urban areas and 33% (n=266) from rural areas. Overall, vaccination coverage was 51% (n=412 girls). Coverage was higher in rural areas (72.6%, n=193 girls) than in urban areas (40%, n=219 girls). This study highlights the challenges and successes of the HPV vaccination program in the Shkodra region during its first year of implementation. Vaccination coverage was higher in rural areas (72.6%) compared to urban areas (40%). Key barriers to vaccine uptake included parental refusal, lack of information, and fear of side effects.

PROSPECTS FOR THE USE OF COMBINED AND MULTIVALENT VACCINES TO CREATE ROBUST ANTI-INFECTIVE IMMUNITY

Abstract Due to the expanding range of "vaccine-controlled" infections and the consolidation of the vaccination calendar, the development and more frequent use of combined and multivalent vaccines for mass population vaccination has been becoming an urgent public health problem. The analysis of scientific literature showing the possibilities, advantages and prospects of using such vaccines within the framework of the National Calendar of Preventive vaccinations in the Russian Federation is carried out. The search for publications was carried out in the databases PubMed, Scopus, Elsevier and e-library as of February 2025. The widespread use of combined and multivalent vaccines is a priority tactic for successful vaccination to create robust, long-term collective immunity to socially significant infections. Numerous clinical studies have established high safety and immunogenicity rates of modern combined vaccines, and facts have been proven to refute myths about their negative impact on children's development. They can reduce the number of injections, doctor visits and the level of psychological trauma associated with them, potential side effects post-immunization and economic costs, increase the level of public confidence and, accordingly, the percentage of vaccination coverage. The use of pentavaccines, including domestic preparations containing a cell-free pertussis component, diphtheria, tetanus toxoids, capsular polysaccharide of Haemophilus influenzae serotype b, as well as an inactivated polio vaccine or recombinant surface antigen of hepatitis B virus, has been becoming especially relevant for the immunization of children. In influenza immunoprophylaxis, preference is given to Russian-made multivalent subunit adjuvant tri- and quadrivalent vaccines. A domestic multivalent pneumococcal vaccine has also been developed. Until 2035, the strategy for developing immunoprophylaxis of infectious diseases in Russia involves expanding the National Calendar to 19 infections from the list of vaccinations for epidemic indications. Priority is given to the prevention of meningococcal and rotavirus infection using quadrivalent subunit vaccines and live pentavalent genetically engineered vaccine and chickenpox (a domestic drug is being tested) in combination with the measles-rubella-mumps vaccine, respectively. Clinical trials with a combined vaccine for preventing influenza and coronavirus infection providing protection against the SARS-CoV-2 virus and four seasonal strains of influenza viruses have begun.

A novel combined quadrivalent self-amplifying mRNA-LNP vaccine provokes protective immunity against acute and chronic toxoplasmosis in mice

BackgroundToxoplasma gondii, an intracellular parasitic protozoan, which infects almost all warm-blooded animals, including humans, causes toxoplasmosis. However, we lack effective drugs and vaccines to control toxoplasmosis, representing a clinical challenge. Therefore, safe and effective vaccines are urgently needed. In this study, a self-replicating mRNA vaccine comprising four T. gondii antigens: ROP18, TGME49_237490, TGME49_268230, and MIC13, named 4x-mRNA-LNP (lipid nanoparticle), was developed, and its protective efficacy was evaluated in mice. MethodsThe expression of this vaccine in eukaryotic Human embryonic kidney 293 T (HEK-293 T) cells and mouse myoblast (C2C12) cells were analyzed, followed by enzyme-linked immunosorbent assay (ELISA) evaluation of the elicited humoral immune response. Subsequently, the vaccine-triggered immune responses in mice were detected, including antibody titers, T lymphocyte subsets, and cytokine levels. Finally, its immunoprotective effects were evaluated after challenging mice with T. gondii PRU oocysts or tachyzoites of different strains and analyzing the pathological changes, parasite loads, and mouse survival time. Western blotting and ELISA confirmed the successful eukaryotic expression and immunogenicity of 4x-mRNA, respectively. Statistical analyses, including the log-rank (Mantel–Cox) test, Student’s t-test, and one-way ANOVA, were performed using GraphPad Prism software. ResultsMice vaccinated with 4x-mRNA-LNP generated higher levels of IgG1 and IgG2a antibodies (P < 0.05) and cytokines (IL-2, IL-4, IL-10, IL-12, IFN-γ) (P < 0.05) compared with the control group. The high specific IgG titer was maintained for at least 10 weeks after the last vaccination. The proportion of CD3+CD4+ T cells and CD3+CD8+ T cells also increased significantly (P < 0.05), along with increased spleen cell proliferation in 4x-mRNA-LNP-vaccinated mice. Notably, limited pathological changes and < 10 fg of parasites/mg were found in the immunized mice tissues post-pathogen challenge. During observation for 30 days, 4x-mRNA-LNP-immunized mice survived significantly longer under challenge with lethal doses of RH, ME49, or WH6 tachyzoites (survival rates = 60%, 80%, and 60%, respectively). Following PRU oocyst challenge, vaccinated mice had notably decreased cyst burdens (72.5%, P < 0.05) compared with control mice.ConclusionsThe 4x-mRNA-LNP vaccine triggered effective long-term antibody levels in mice, thus representing a promising candidate to further develop anti-toxoplasmosis vaccines.Graphical

Public Health Impact of Potential Infant MenACWY Vaccination Strategies in Spain

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.

Immunogenicity of primary and booster MenACWY-TT vaccination in older adults and the importance of IgM

Adults aged 65 years and older are at increased risk for infectious diseases, including invasive meningococcal disease (IMD), yet data on meningococcal vaccine immunogenicity in this population remain limited. In this randomized clinical trial (CTIS: 2024-513640-29-00, 13-05-2024), 222 older adults (65–85 years) received a quadrivalent meningococcal conjugate vaccine (MenACWY-TT), with 104 adults receiving a booster dose one year later. Serum bactericidal activity (rSBA) and polysaccharide-specific IgG and IgM concentrations were assessed. One month post-primary vaccination, 91–98% of participants had protective rSBA titers (≥8). Booster vaccination transiently increased bactericidal responses, but titers returned to pre-booster values within a year for MenC, -W, and -Y. rSBA titers correlated stronger with IgM than IgG, particularly for MenW and -Y. Interestingly, IgM depletion markedly reduced rSBA titers, while IgG depletion had minimal impact. These findings highlight that MenACWY-TT vaccination elicits functional antibody responses in older adults, largely driven by IgM.

HPV Vaccine Effectiveness by Age, Age at Vaccination, and Timing of Vaccination Relative to Age at First Sex among Men who Have Sex with Men - Seattle, Washington, 2018-2020.

We evaluated human papillomavirus (HPV) vaccine effectiveness (VE) against prevalent anal HPV among men who have sex with men (MSM) by age, age at vaccination, and age at vaccination relative to age at first sex. Residual anal specimens from 1092 MSM ages 18-45 years attending a Seattle, Washington sexual health clinic in 2018-2020 were tested for 28 HPV types. Demographic, clinical, sexual behavioral, and HPV vaccination data were extracted from clinic and electronic medical records. We calculated adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) for associations between vaccination (≥1 dose of any HPV vaccine) and quadrivalent HPV vaccine (4vHPV)-type infection, by age group (18-26, 27-35, 36-45 years), vaccination age (among age groups 18-26, 27-35 years) and vaccination age relative to first sex (among those 18-26 years). Analyses were adjusted for race and ethnicity, pre-exposure prophylaxis use for HIV prevention, and lifetime number of sex partners. VE was calculated as (1-aPR)x100. Among persons aged 18-26 years, 4vHPV-type HPV prevalence was lower among those vaccinated before first sex (aPR = 0.12[95%CI:0.02-0.87]; VE = 88%) or at <18 years of age (aPR = 0.22[95%CI:0.07-0.68]; VE = 78%) versus unvaccinated, but no VE was observed in those vaccinated at 18-26 years. Among persons aged 27-35 years, 4vHPV-type HPV prevalence was lower among those vaccinated at 18-26 years versus unvaccinated (aPR = 0.56[95%CI:0.36-0.87]; VE = 44%). No VE was observed in persons aged 27-35 or 36-45 years who were vaccinated at >26 years. Results highlight the importance of routine HPV vaccination in adolescence and support efforts to increase catch-up vaccination among MSM.

Corrigendum to ’Safety of quadrivalent recombinant influenza vaccine in pregnant persons and their infants’ [AJOG Global Reports Volume 4, Issue 4, November 2024, 100395

Corrigendum to ’Safety of quadrivalent recombinant influenza vaccine in pregnant persons and their infants’ [AJOG Global Reports Volume 4, Issue 4, November 2024, 100395

Optimization for the production of a dengue live-attenuated Quadrivalent vaccine in Vero cells grown on microcarriers

Optimization for the production of a dengue live-attenuated Quadrivalent vaccine in Vero cells grown on microcarriers

MF59-like adjuvant containing yeast-derived squalene enhances the humoral immune response to cell-derived influenza vaccine.

The aims of this study were to assess the adjuvant properties of an MF59-like adjuvant containing yeast-derived squalene (MF59-like YD) in a cell-based quadrivalent influenza vaccine (QIV) and to investigate the potential mechanisms of action. MF59-like adjuvants containing either yeast-derived or shark-derived squalene were incorporated into QIV formulations. Antigen-specific immune responses in mouse serum were evaluated via enzyme-linked immunosorbent assays (ELISAs), hemagglutination inhibition (HI) assays, and microneutralization (MN) assays. The effects and mechanisms of action of the adjuvants were further analyzed by analyzing mouse spleen germinal center (GC) cell activation via flow cytometry. MF59-like YD significantly increased the humoral immune responses induced by QIVs in mice, in particular, the titers of HI and MN antibodies against homologous and heterologous virus subtypes. Mechanistically, MF59-like YD increased the immune response to influenza vaccines by activating T follicular helper (Tfh) and B cells in the GC. Given the greater availability of yeast-derived squalene and the finding that its adjuvant efficacy was comparable to that of shark-derived squalene, we propose that the MF59-like YD adjuvant is a promising alternative adjuvant for future influenza vaccines.

Adverse events affecting recovery from seasonal influenza vaccination in the hypertensive population: A population-based pharmacovigilance analysis.

Seasonal influenza vaccination is crucial for preventing influenza and its complications. Data from the United States Vaccine Adverse Event Reporting System (VAERS) indicate a higher proportion of adverse events (AEs) after influenza vaccination in hypertensive people. However, there is limited evidence on AEs in hypertensive people following seasonal influenza vaccination. We identified 4647 individuals aged 18 years or older with a history of hypertension who received seasonal influenza vaccination and 6380 seasonal influenza-vaccine-induced AEs between 1 January 2013 and 23 June 2023 from VAERS. We identified two groups for comparison: recovery and no recovery from seasonal influenza-vaccine-induced AEs. Propensity score matching (PSM) was performed to adjust for potential confounding factors, including demographic characteristics (age, sex, and region) and season of onset. Cox regression analysis was used to calculate the risk ratio of reported adverse events (AEs) that affected recovery after seasonal influenza vaccination. Most AEs were nonserious and occurred within 48 hours. The most common AEs were general disorders and administration site conditions (therapeutic and non-therapeutic responses, inflammation) and musculoskeletal and connective tissue disorders (musculoskeletal and connective tissue pain and discomfort, bursal disorders, joint-related signs, and symptoms). All three types of seasonal influenza vaccines were associated with injection site reactions (47.07% trivalent influenza vaccine [TIA], hazard ratio, HR 2.04, 95% confidence interval, CI 1.22-3.40; 20.00% quadrivalent influenza vaccine [QIA], HR 2.81, 95% CI, 1.81-4.37; 67.48% influenza vaccine, unknown manufacturer [FLUX], HR 2.83, 95% CI, 1.12-7.15) and were the AEs affecting the largest proportion of delayed recoveries in the hypertensive population. Potential AEs following seasonal influenza vaccination may affect the recovery of the hypertensive population. The majority of AEs reported were general disorders, predominantly injection site reactions, and nonserious.

Understanding the value of meningococcal vaccination for adolescents and young adults in the United States: insights from a steady-state modelling approach

BackgroundA two-dose series of quadrivalent meningococcal conjugate vaccine (MenACWY) is recommended for the prevention of invasive meningococcal disease (IMD) in adolescents in the United States. In June 2024, the Advisory Committee on Immunization Practices discussed plans to review the adolescent meningococcal vaccination schedule. Various options are under consideration, including removing the first dose of MenACWY at age 11–12 years.ObjectivesWe evaluated the public health impact and cost-effectiveness of administering one or two doses of MenACWY compared to a scenario with no vaccination.MethodsWe constructed an incidence-based population model to compare costs and quality-adjusted life years (QALYs) associated with different vaccination schedules in a cohort of 11–25 year-olds, from a societal perspective, over a lifetime analytic horizon for outcomes related to death and disabilities. The main analyses compared various scenarios of MenACWY (Q) and MenB schedules to no vaccination. Further scenarios examined the impact of alternative assumptions applied to the first and/or second dose of MenACWY.ResultsCompared to no vaccination, 2 doses of MenACWY and 2 doses of MenB vaccine was projected to reduce IMD cases by 277 per year, resulting in an incremental cost-effectiveness ratio (ICER) of $625,322/QALY. Administering 2 doses of MenACWY was projected to reduce the annual number of IMD cases by 275 at an ICER of $438,948/QALY, which increased to 631 at an ICER of $190,030/QALY when herd immunity was considered. Alternatively, if only 1 dose of MenACWY was administered, the reduction in cases would be 253 if administered at 11–12 years old and 125 if given at 16 years, with ICERs of $252,249 per QALY and $352,169/QALY, respectively. Assuming a 25% increase in vaccination coverage rate, one MenACWY dose at 16 years resulted in 156 cases avoided.ConclusionsThe two doses of MenACWY that are currently recommended play a crucial role in reducing the burden of IMD and the first dose contributes significantly (≥ 90%) to this reduction. It is essential to take this finding into account when considering any updates to the adolescent meningococcal vaccination schedule in the United States.

A protocol for high-dose quadrivalent influenza vaccine effectiveness in the community and long-term care facilities using electronic health records.

Since the 2022-2023 season in Portugal, a high-dose quadrivalent influenza vaccine is freely available for individuals living in long-term care facilities (LTCF). In 2024-2025, vaccination was extended to community-dwelling individuals aged ≥85 years. Given the scarcity of reported high-dose influenza vaccine effectiveness (IVE) estimates for this population, this study aims to estimate the high-dose relative and absolute IVE. A retrospective cohort study using data from electronic health records databases (EHR) will be implemented, using two cohorts, one of individuals vaccinated with influenza vaccine (to estimate relative IVE) and another of individuals eligible for the high-dose quadrivalent influenza vaccine (to estimate absolute IVE). We will consider two subgroups for both cohorts: individuals living in LTCF and community-dwelling individuals aged ≥85. We will use a fixed cohort approach, defining the eligible population by age at the vaccination campaign(s) start and living status. The outcomes are based on the primary cause of hospital admission. The reference population database will be defined by linking EHR on vaccination, comorbidities, and hospitalisations using a unique identifier through a deterministic data linkage procedure, and influenza vaccination status will be assessed retrospectively. We will use Cox proportional hazards regression models to estimate the hazard ratio (HR), considering as event the first hospitalisation due to influenza-like-illness and as exposure the vaccination status. IVE will be estimated as one minus the confounder-adjusted HR of vaccinated with the high-dose quadrivalent influenza vaccine vs vaccinated with standard dose (to estimate relative IVE) or unvaccinated (to estimate absolute IVE). While challenges such as EHR constraints and potential reporting bias pose limitations, using routinely collected data has successfully estimated COVID-19 VE and enables precise monitoring of VE with higher representativeness. The results of this study will inform the Health Ministry on the future influenza vaccine programme in Portugal.

Vaccine effectiveness against anal HPV infection among men with HIV who have sex with men attending sexual health clinics in three United States cities, 2018-2023.

Men who have sex with men (MSM) with HIV are disproportionately affected by human papillomavirus (HPV) and related diseases. We assessed HPV vaccine effectiveness (VE) against anal HPV among MSM with HIV. During 2018-2023, residual anal specimens from MSM with HIV, aged 18-45 years, attending sexual health clinics in three U.S. cities were collected and tested for HPV. Demographic and vaccination information were obtained from clinic records or immunization registries. Timing of vaccination relative to HIV acquisition was unknown. Log-binomial regression was used to calculate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for associations between vaccination (≥1 dose) and quadrivalent vaccine (4vHPV)-type infection, adjusting for city. Models were stratified by age group (18-26, 27-45 years). VE was calculated as (1-aPR) x 100. Among 224 persons aged 18-26 years, 54% were vaccinated. Compared with unvaccinated persons, 4vHPV-type prevalence was lower in those vaccinated at age <18 (aPR=0.31, 95% CI:0.14-0.72, VE=69%) and ≥2 years before specimen collection (aPR=0.54, 95% CI:0.31-0.92, VE=46%). Among 700 persons aged 27-45 years, 17% were vaccinated. Compared with unvaccinated persons, 4vHPV-type prevalence was lower in those vaccinated at ages 18-26 (aPR=0.63, 95% CI:0.45-0.89, VE=37%) and ≥2 years before specimen collection (aPR=0.63, 95% CI:0.46-0.86, VE=37%). While timing of vaccination relative to HIV acquisition was unknown, we found significant VE against prevalent HPV infection in adult MSM with HIV. Within each age group, VE was higher with younger age at vaccination.