Monovalent Vaccine Research Articles

The Apparent Lack of the Risk of Intussusception Immediately After Rotavirus Vaccination Among Japanese Infants

Rotavirus vaccines carry a small risk of intussusception mainly 1–7 days after vaccination in the United States of America, Europe, Australia, and Latin America where the background rate of intussusception is relatively low. Such risks are undetectable in Africa and India where the background rate is the lowest. Because few studies were carried out in high-background-rate countries such as Japan, we examined how intussusception occurred in infants living in Akita prefecture, Japan, while the vaccines were sold in the private market. Between 2011 and 2018, an estimated 21,677 infants (46%) were vaccinated and 54% were not. Through a retrospective survey of medical records in 18 hospitals in the prefecture, we identified 58 infants, 28 of whom were vaccinated and 30 of whom were unvaccinated, as having intussusception that met level 1 of the Brighton criteria. Thus, the intussusception rate was 123 per 100,000 infant-years (95% confidence interval [CI]: 94–160). Despite the high rate, none developed intussusception 1–7 days after the first dose of either the monovalent human rotavirus vaccine (GSK) or the pentavalent human–bovine reassortant vaccine (MSD). The incidence rate ratio of vaccinated to unvaccinated infants between 42 and 245 days of life was estimated at 0.96 (95%CI: 0.43–2.1; p = 0.92). Given that over 95% of infants received the first dose before 15 weeks of age, the risk of intussusception associated with the rotavirus vaccines in high-incidence-rate countries can be reduced to a minimum by adhering to the recommended schedule at 2, 3, and 4 months of age.

Effectiveness of Original Monovalent and Bivalent COVID-19 Vaccines Against COVID-19-Associated Hospitalization and Severe In-Hospital Outcomes Among Adults in the United States, September 2022-August 2023.

Assessments of COVID-19 vaccine effectiveness are needed to monitor the protection provided by updated vaccines against severe COVID-19. We evaluated the effectiveness of original monovalent and bivalent (ancestral strain and Omicron BA.4/5) COVID-19 vaccination against COVID-19-associated hospitalization and severe in-hospital outcomes. During September 8, 2022 to August 31, 2023, adults aged ≥ 18 years hospitalized with COVID-19-like illness were enrolled at 26 hospitals in 20 US states. Using a test-negative case-control design, we estimated vaccine effectiveness (VE) with multivariable logistic regression adjusted for age, sex, race/ethnicity, admission date, and geographic region. Among 7028 patients, 2924 (41.6%) were COVID-19 case patients, and 4104 (58.4%) were control patients. Compared to unvaccinated patients, absolute VE against COVID-19-associated hospitalization was 6% (-7%-17%) for original monovalent doses only (median time since last dose [IQR] = 421 days [304-571]), 52% (39%-61%) for a bivalent dose received 7-89 days earlier, and 13% (-10%-31%) for a bivalent dose received 90-179 days earlier. Absolute VE against COVID-19-associated invasive mechanical ventilation or death was 51% (34%-63%) for original monovalent doses only, 61% (35%-77%) for a bivalent dose received 7-89 days earlier, and 50% (11%-71%) for a bivalent dose received 90-179 days earlier. Bivalent vaccination provided protection against COVID-19-associated hospitalization and severe in-hospital outcomes within 3 months of receipt, followed by a decline in protection to a level similar to that remaining from previous original monovalent vaccination by 3-6 months. These results underscore the benefit of remaining up to date with recommended COVID-19 vaccines.

Effectiveness of Bivalent mRNA Vaccines in Preventing Symptomatic SARS-CoV-2 Infection-Increasing Community Access to Testing Program, United States, January-September 2023.

On September 2, 2022, bivalent COVID-19 mRNA vaccines, were recommended to address reduced effectiveness of COVID-19 monovalent vaccines during SARS-CoV-2 Omicron variant predominance. Using national pharmacy-based SARS-CoV-2 testing program data from January 15 to September 11, 2023, this test-negative, case-control design study assessed bivalent COVID-19 vaccine effectiveness (VE) against symptomatic infection. VE against symptomatic infection of a bivalent dose between 2 weeks and 1 month after bivalent vaccination ranged from 46% (95% CI: 38%-52%) for those aged ≥ 65 years to 61% (95% CI 41%-75%) for those aged 12-17 years. Bivalent vaccines protected against symptomatic infection. However, effectiveness waned over time, emphasizing the need to stay up to date with COVID-19 vaccination.

Divergence of variant antibodies following SARS-CoV-2 booster vaccines in myeloma and impact of hybrid immunity

Hematological malignancies are associated with an increased risk of complications during SARS-CoV-2 infections. Primary series or monovalent booster vaccines reduce disease severity, hospitalization, and death among multiple myeloma patients. We characterized virus-neutralizing and spike-binding antibody profiles following monovalent (WA1) or bivalent (WA1/BA.5) SARS-CoV-2 booster vaccination in MM patients. Bivalent vaccination improved the breadth of binding antibodies but not neutralization activity against contemporary variants. Hybrid immunity and immune imprinting impact vaccine-elicited immunity.

Vaccination against respiratory syncytial virus (RSV)-For the protection of infants and older adults

Respiratory syncytial virus (RSV) is afrequent cause of respiratory infections in all age groups. Infections in infants and older adults frequently result in severe disease and complications. There is no specific antiviral treatment against RSV. The characterization of the structure of the fusion (F) protein in its immunogenic prefusion conformation has enabled the development of novel vaccines directed against the prefusion protein as the antigen. These include an adjuvanted monovalent vaccine (Arexvy) and anonadjuvanted bivalent vaccine (Abrysvo). Both are approved and indicated for use in older adults, in whom they have been shown to be over 80% effective in the protection against symptomatic RSV infections and associated lower respiratory tract diseases. Abrysvo is approved for use in pregnancy to protect the newborn through the transplacental transfer of high-titer maternal antibodies. The vaccine has been shown to have an efficacy of over 80% in the first 3 months of life to protect the infant from severe RSV-associated lower respiratory disease but slightly deceases after an age of 6 months. The clinical studies demonstrated the safety of the vaccines in both adults and pregnant women. The rate of undesired side effects was low in all studies and severe side effects were very rare. The new vaccines are efficacious new tools to prevent RSV-associated disease and complications in high-risk groups. For infants, an alternative strategy can be passive immunization with monoclonal antibodies, including the recently developed nirsevimab, which has also shown high efficacy.

Comparative Analysis of the Neutralizing Capacity of Monovalent and Bivalent Formulations of Betuvax-CoV-2, a Subunit Recombinant COVID-19 Vaccine, Against Various Strains of SARS-CoV-2

SARS-CoV-2, the causal agent of the COVID-19 pandemic, is characterized by rapid evolution, which poses a significant public health challenge. Effective vaccines that provide robust protection, elicit strong immune responses, exhibit favorable safety profiles, and enable cost-effective large-scale production are crucial. The RBD-Fc-based Betuvax-CoV-2 vaccine has previously demonstrated a favorable safety profile and induced a significant anti-SARS-CoV-2 humoral immune response in clinical trials. Due to the rapid evolution and emergence of new SARS-CoV-2 strains, the relevance of bivalent vaccine formulations has increased. Methods: This study compared the neutralizing capacity of monovalent and bivalent vaccine formulations against different SARS-CoV-2 strains detected with a SARS-CoV-2 microneutralization assay (MNT). Findings: The monovalent Wuhan-based vaccine generated neutralizing antibodies against the Wuhan and Omicron BA.2 variants but not the distinct Omicron BQ.1 strain. Conversely, the monovalent BA.2-based vaccine induced neutralizing antibodies against both Omicron strains but not Wuhan. While the bivalent Wuhan and BA.2-based vaccine was effective against strains containing the same antigens, it was insufficient to neutralize the distinctive BQ.1 strain at a small dosage. Interpretation: These findings suggest that the vaccine composition should closely match the circulating SARS-CoV-2 strain to elicit the optimal neutralizing antibody response and include the appropriate dosage. Moreover, this study did not find additional advantages of using the bivalent form over the monovalent form for the vaccination against a single prevailing SARS-CoV-2 strain.

Cellular and humoral immunity and IgG subclass distribution after omicron XBB.1.5 monovalent vaccination in Japan

BackgroundUp to seven doses of coronavirus disease 2019 (COVID-19) mRNA vaccines (BNT162b2) were administered to Japanese healthcare workers, until February 2024. The monovalent Omicron XBB.1.5 vaccine (hereafter called XBB.1.5 vaccine) was used for dose 7. ObjectiveAlthough the XBB.1.5 vaccine has been reported to induce a robust increase in neutralizing antibodies against the currently circulating Omicron variant BA.2.86, little is known about its serological effects in Japan, where the BNT162b2 mRNA vaccine is the most frequently administered in the world. Study designTwenty-five recipients of the XBB.1.5 vaccine, categorized as seronegative (n = 18) or seropositive (n = 7) based on their recent history of COVID-19, were analyzed. Neutralizing antibody titers against Omicron subvariants, receptor binding domain (RBD) IgG levels, IgG subclass distribution, and T-cell responses were assessed. ResultsWe found a significant increase in neutralizing antibody titers against XBB.1.5 and BA.2.86 variants following XBB.1.5 vaccination, particularly in seropositive individuals. No significant change in total RBD IgG levels was observed, indicating efficient induction of antibodies targeting regions outside the RBD by XBB.1.5 vaccination. IgG subclass analysis demonstrated no significant subclass switching after vaccination. T-cell responses against the virus were comparable between seropositive and seronegative groups. ConclusionsThe study suggests that XBB.1.5 vaccination enhances humoral immunity against Omicron variants without significant IgG subclass switching. However, some individuals with low pre-vaccination IgG titers did not exhibit increased antibody levels post-vaccination, raising concerns about potential immune tolerance.

Antitumor activity of PAbs generated by immunization with a novel HER3-targeting protein-based vaccine candidate in preclinical models.

Despite the cumulative evidence supporting HER3 as a target for antitumor therapies, no agents targeting HER3 have been approved for cancer treatment. Most of the agents evaluated in preclinical and clinical trials have been specific monoclonal antibodies (MAbs), with few examples of active immunotherapy directed against this receptor. However, some cancer vaccine formats may generate polyclonal antibodies (PAbs) that replicate the diverse effector mechanisms of MAbs, including ligand neutralization and receptor degradation. In this study, we developed a protein subunit-based monovalent vaccine candidate targeting the extracellular domain (ECD) of HER3. Immunization of mice with a formulation targeting murine ErbB3-ECD successfully overcome tolerance to this self-antigen, inducing high titers of ErbB3-specific PAbs. The antitumor potential of this formulation and the induced PAbs was demonstrated in vivo and in vitro in an ErbB3-overexpressing 3LL-D122-derived tumor model. The immunogenicity of the HER3-ECD-based vaccine candidate was confirmed by the induction of high titers of HER3-specific PAbs. Consistent with the initial results, HER3-ECD-targeting PAbs were cytotoxic in several human epithelial tumor cell lines and exerted antitumor effects in vivo. These results support the value of HER3 as a tumor antigen and the effector mechanisms of HER3-specific therapeutic MAbs, while suggesting the potential of the proposed vaccine candidate for the treatment of HER3-expressing carcinomas.

Effectiveness of the original monovalent mRNA COVID-19 vaccination series against hospitalization for COVID-19-associated venous thromboembolism.

COVID-19 is a strong risk factor for venous thromboembolism (VTE). Few studies have evaluated the effectiveness of COVID-19 vaccination in preventing hospitalization for COVID-19 with VTE. Adults hospitalized at 21 sites between March 2021 and October 2022 with symptoms of acute respiratory illness were assessed for COVID-19, completion of the original monovalent mRNA COVID-19 vaccination series, and VTE. Prevalence of VTE was compared between unvaccinated and vaccinated patients with COVID-19. Vaccine effectiveness in preventing COVID-19 hospitalization with VTE was calculated using a test negative design. Vaccine effectiveness was also stratified by predominant circulating SARS-CoV-2 variant. Among 18,811 patients (median age 63 [IQR:50-73], 49% women, 59% non-Hispanic White, 20% non-Hispanic Black, 14% Hispanic, and median of 2 comorbid conditions [IQR:1-3]), 9,792 were admitted with COVID-19 (44% vaccinated) and 9,019 were test-negative controls (73% vaccinated). Among patients with COVID-19, 601 were diagnosed with VTE by hospital day 28, of whom 170 were vaccinated. VTE was more common among unvaccinated than vaccinated COVID-19 patients (7.8% versus 4.0%; p=0.001). Vaccine effectiveness against COVID-19 hospitalization with VTE was 84% (95% CI: 80-87%) overall. Vaccine effectiveness stratified by predominant circulating variant was 88% (73-95%) for alpha, 93% (90-95%) for delta, and 68% (58-76%) for omicron variants. Vaccination with the original monovalent mRNA series was associated with a decrease in COVID-19 hospitalization with VTE, though data detailing prior history of VTE and use of anticoagulation were not available. These findings will inform risk-benefit considerations for those considering vaccination.

Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review.

This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines. A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not. We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1-odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization. Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.

Long-term outcomes of high-risk human papillomavirus in anal infection support HPV men vaccination

Abstract Introduction/Objective The clinical laboratory in a local hospital has an important role in population surveillance. The clinical laboratory performs analyses on patients admitted to the hospital as inpatients or critical patients and it is also a reference point for people’s health check-ups and health surveillance. Infectious diseases normally have severe symptoms. To ensure benefits from therapeutic treatment, a timely diagnosis is necessary. The human papillomavirus (HPV) virus is among the most diagnosed sexually transmitted infections worldwide, and the male gender is not exempt from it. In fact, 1 out of 3 male individuals is infected with HPV and 1 out of 5 male individuals is infected with a high-risk strain (1). In Italy, vaccination is underway for women only. Vaccine prevention extended to male individuals could lead to a halving of HPV cases. Methods/Case Report From 2018 to 2022, we performed 7362 HPV tests using DNA extraction technique (QiaSimphony) and real-time Multiplex PCR (SeeGene 28 strains). Results (if a Case Study enter NA) 3762 out of 7362 HPV tests performed were positive for one (2059 patients) or more (1969 patients) HPV strains. Women, who are more aware of prevention, are more represented in our sample of subjects. The tests performed on women are 6499 and half (3331) are positive for at least one strain of HPV. Regarding men, 863 tests were performed. About half (431 patients) were positive for at least one HPV strain. Noteworthy, out of 175 anal HPV tests, 48% were positive and 1 patient had squamous cell carcinoma. Furthermore, in our male patients tested 2 - 12% had low or medium-risk injuries. In total, out of 7529 tests carried out from 2018 to 2022, over than 50% were found to be high-risk viral strains (5231). Of these, however, approximately half (2781) are now preventable with the monovalent HPV vaccine (strains covered: 6, 11, 16, 18, 31, 33, 45, 52, 58). Conclusion The Ospedale Isola Tiberina – Gemelli Isola is an Institution in the center of Rome, Italy. It is also a reference center for birthrates and women’s prevention. Therefore, our Institution is very efficient in raising awareness of the prevention of HPV-related cancer. Current data indicate that male cases are not negligible, being positive in almost 50% of anal tests, and associated with an increased risk of the related cancers. These data can have an important impact on the Italian population, both in terms of the spread of HPV and healthcare burden and in terms of high healthcare costs.

Broad immunogenicity to prior SARS-CoV-2 strains and JN.1 variant elicited by XBB.1.5 vaccination in nursing home residents.

SARS-CoV-2 vaccination has reduced hospitalization and mortality for nursing home residents (NHRs) but emerging variants and waning immunity challenge vaccine effectiveness. This study assesses the immunogenicity of the most recent XBB.1.5 monovalent vaccine to variant strains among NHRs. Participants were subset of a longitudinal study of consented NHRs and Healthcare workers (HCWs) who have received serial blood draws to assess immunogenicity with each SARS-CoV-2 mRNA vaccine dose. We report data on participants who received the XBB.1.5 monovalent vaccine post-FDA approval in Fall 2023. NHRs were categorized by whether they had an interval SARS-CoV-2 infection between their first bivalent vaccine dose and their XBB.1.5 monovalent vaccination. The sample included 61 NHRs [median age 76 (IQR 68-86), 51% female] and 28 HCWs [median age 45 (IQR 31-58), 46% female). After XBB.1.5 vaccination, a robust geometric mean fold rise (GMFR) in XBB.1.5-specific neutralizing antibody titers was observed:17.3 (95% confidence interval [CI] 9.3, 32.4) and NHRs with interval infection and 11.3 (95% CI 5, 25.4) in those without and 13.6 (95% CI 8.4,22) in HCWs. For JN.1-specific titers, GMFRs were 14.9 (95% CI 7.9, 28) and 6.5 (95% CI 3.3, 13.1) in NHRs with and without interval infection, and 11.4 (95% CI 6.2, 20.9) in HCWs. NHRs with interval SARS-CoV-2 infection had higher titers across all analyzed strains analyzed. The XBB.1.5 vaccine significantly elevates Omicron-specific neutralizing antibody titers to XBB.1.5 and JN.1 strains in both NHRs and HCWs with more pronounced in those previously infected with SARS-CoV-2 since bivalent vaccination.

Preclinical immunogenicity and safety of hemagglutinin-encoding modRNA influenza vaccines

Seasonal epidemics of influenza viruses are responsible for a significant global public health burden. Vaccination remains the most effective way to prevent infection; however, due to the persistence of antigenic drift, vaccines must be updated annually. The selection of vaccine strains occurs months in advance of the influenza season to allow adequate time for production in eggs. RNA vaccines offer the potential to accelerate production and improve efficacy of influenza vaccines. We leveraged the nucleoside-modified RNA (modRNA) platform technology and lipid nanoparticle formulation process of the COVID-19 mRNA vaccine (BNT162b2; Comirnaty®) to create modRNA vaccines encoding hemagglutinin (HA) (modRNA-HA) for seasonal human influenza strains and evaluated their preclinical immunogenicity and toxicity. In mice, a monovalent modRNA vaccine encoding an H1 HA demonstrated robust antibody responses, HA-specific Th1-type CD4+ T cell responses, and HA-specific CD8+ T cell responses. In rhesus and cynomolgus macaques, the vaccine exhibited durable functional antibody responses and HA-specific IFN-γ+ CD4+ T cell responses. Immunization of mice with monovalent, trivalent, and quadrivalent modRNA-HA vaccines generated functional antibody responses targeting the seasonal influenza virus(es) encoded in the vaccines that were greater than, or similar to, those of a licensed quadrivalent influenza vaccine. Monovalent and quadrivalent modRNA-HA vaccines were well-tolerated by Wistar Han rats, with no evidence of systemic toxicity. These nonclinical immunogenicity and safety data support further evaluation of the modRNA-HA vaccines in clinical studies.

Determination of T cell response against XBB variants in adults who received either monovalent wild type inactivated whole virus or mRNA vaccine or bivalent WT/BA.4-5 COVID-19 mRNA vaccine as the additional booster

ObjectivesAs the SARS-CoV-2 virus evolves more rapidly than vaccines are updated, T cell immunity potentially confers protection against disease progression and death from new variants. In this study, we aimed to assess whether the current boosting vaccination schemes offer sufficient T cell protection against new SARS-CoV-2 variants. Methods. 292 adults who had received the second booster of either monovalent wild type vaccines (inactivated virus or mRNA) (cohort 1) or the second/third booster of bivalent WT/BA.4-5 mRNA vaccine (cohort 2) were recruited in Hong Kong. All participants showed no serological evidence of recent infection of SARS-CoV-2. Blood samples of each participant were collected before and one-month after receiving the booster. T cell and antibody responses were determined by flow cytometry and neutralization test respectively. Results. Among all vaccination strategies, only the adults who had received the bivalent vaccine as the third booster dose significantly elicited T cell responses to the XBB variant. Either monovalent or bivalent mRNA but not inactivated virus vaccine as the second/third booster induced antibody against different XBB variants. Conclusions. Receiving bivalent mRNA vaccine as the third booster is preferrable to induce both T cell and antibody responses against XBB.

Enhancing Omicron Sublineage Neutralization: Insights From Bivalent and Monovalent COVID-19 Booster Vaccines and Recent SARS-CoV-2 Omicron Variant Infections.

Omicron variants have rapidly diversified into sublineages with mutations that enhance immune evasion, posing challenges for vaccination and antibody responses. This study aimed to compare serum cross-neutralizing antibody responses against various SARS-CoV-2 Omicron sublineages (BA.1, BA.5, XBB.1.17.1, FK.1.1, and JN.1) in recipients of monovalent COVID-19 boosters, bivalent booster recipients, and individuals who had recovered from Omicron BA.5 infections. We conducted a micro-neutralization assay on serum samples from monovalent BNT162b2 booster recipients (N = 54), bivalent BNT162b2 booster recipients (N = 24), and SARS-CoV-2 Omicron BA.5-recovered individuals (N = 13). The history of SARS-CoV-2 Omicron infection was assessed using ELISA against the SARS-CoV-2 NP protein. Bivalent booster recipients exhibited significantly enhanced neutralization efficacy against Omicron sublineages compared to those who had received monovalent booster vaccinations. Omicron BA.5-recovered individuals displayed similar neutralizing antibodies (NAbs) to the bivalent booster recipients. Despite the improved neutralization in bivalent recipients and BA.5-recovered individuals, there were limitations in neutralization against the recently emerged Omicron subvariants: XBB.1.17.1 FK.1.1, and JN.1. In both monovalent and bivalent booster recipients, a history of Omicron breakthrough infection was associated with relatively higher geometric mean titers of NAbs against Omicron BA.1, BA.5, and XBB.1.17.1 variants. This study underscores the intricate interplay between vaccination strategies, immune imprinting, and the dynamic landscape of SARS-CoV-2 variants. Although bivalent boosters enhance neutralization, addressing the challenge of emerging sublineages like XBB.1.17.1, FK.1.1, and JN.1 may necessitate the development of tailored vaccines, underscoring the need for ongoing adaptation to effectively combat this highly mutable virus.

Detection of PCV2d in Vaccinated Pigs in Colombia and Prediction of Vaccine T Cell Epitope Coverage against Circulating Strains Using EpiCC Analysis.

Porcine circovirus type 2 (PCV2) is strongly linked to a group of syndromes referred to as porcine-circovirus-associated diseases (PCVADs), which are controlled through vaccination; however, this does not induce sterilizing immunity but is instead involved in the evolution of the virus and is considered a factor in vaccine failure. This study sampled 84 herds (167 pigs) vaccinated against PCV2 and with clinical signs of PCVADs in five provinces across Colombia. PCV2 was identified and further characterized at the molecular level via genotyping and phylogenetic reconstructions. In addition, PCV2-associated lesions were examined via histopathology. Furthermore, the PCV2-Cap sequences retrieved were compared with three vaccines via the EpiCC tool and T cell epitope coverage. The prevalence of PCV2 was 82% in pigs and 92.9% in herds. The highest viral loads were identified in lymphoid tissue, and PCV2d emerged as the most predominant in pigs and herds (93.4% and 92.3%). Sequences for PCV2-ORF2 (n = 57; 55 PCV2d and 2 PCV2a) were determined, and PCV2d sequences were highly similar. The most common pneumonia pattern was suppurative bronchopneumonia, while the most common lung lesion was exudation in the airways; in lymphoid tissue, there was lymphoid depletion. The bivalent vaccine (PCV2a and PCVb) exhibited a higher EpiCC score (8.36) and T cell epitope coverage (80.6%) than monovalent PCV2a vaccines. In conclusion, PCV2d currently circulates widely in Colombia. Despite vaccination, there are clinical cases of PCV2, and immunoinformatic analyses demonstrate that bivalent vaccines improved the average coverage.

Symptoms Six Weeks After COVID-19 Are Reduced Among US Health Care Personnel Receiving Additional Vaccine Doses During the Omicron Period, December 2021-April 2022.

The objective of this study was to test the hypothesis that subsequent doses of the coronavirus disease 2019 (COVID-19) vaccine are associated with lower incidence of COVID-19-like symptoms at 6 weeks after infection. This study was a case-control analysis of health care personnel in an ongoing multicenter COVID-19 vaccine effectiveness study. We enrolled participants at the time of COVID-19-like symptoms between December 19, 2021, and April 27, 2022, which corresponded to the early Omicron-predominant period after original monovalent severe acute respiratory syndrome coronavirus 2 additional vaccination doses became available. Our outcome was self-reported symptoms completed 6 weeks after the onset of symptoms. We enrolled 2478 participants, of whom 1422 (57%) had COVID-19. The prevalence of symptoms at 6 weeks was 26% (n = 373) in those with COVID-19 and 18% (n = 195) in those without COVID-19. Fatigue (11%) and difficulty sleeping (7%) were most strongly associated with COVID-19. A total of 1643 (66%) participants received a subsequent vaccine dose (after the primary series). Participants with COVID-19 who had received a subsequent vaccination had lower odds of symptoms at 6 weeks (adjusted odds ratio [aOR], 0.55; 95% CI, 0.43-0.70), but this relationship was not observed in those without COVID-19 (aOR, 0.87; 95% CI, 0.59-1.29). Health care personnel who received subsequent doses of original monovalent COVID-19 vaccine had a lower prevalence of symptoms at 6 weeks than those that did not.

Evaluation of a Quadrivalent Shigella flexneri Serotype 2a, 3a, 6, and Shigella sonnei O-Specific Polysaccharide and IpaB MAPS Vaccine

Background: Shigellosis is the leading cause of diarrheal deaths worldwide and is particularly dangerous in children under 5 years of age in low- and middle-income countries. Additionally, the rise in antibiotic resistance has highlighted the need for an effective Shigella vaccine. Previously, we have used the Multiple Antigen-Presenting System (MAPS) technology to generate monovalent and quadrivalent Salmonella MAPS vaccines that induce functional antibodies against Salmonella components. Methods: In this work, we detail the development of several monovalent vaccines using O-specific polysaccharides (OSPs) from four dominant serotypes, S. flexneri 2a, 3a, and 6, and S. sonnei. We tested several rhizavidin (rhavi) fusion proteins and selected a Shigella-specific protein IpaB. Quadrivalent MAPS were made with Rhavi-IpaB protein and tested in rabbits for immunogenicity. Results: Individual MAPS vaccines generated robust, functional antibody responses against both IpaB and the individual OSP component. Antibodies to IpaB were effective across Shigella serotypes. We also demonstrate that the OSP antibodies generated are specific to each homologous Shigella O type by performing ELISA and bactericidal assays. We combined the components of each MAPS vaccine to formulate a quadrivalent MAPS vaccine which elicited similar antibody and bactericidal responses compared to their monovalent counterparts. Finally, we show that the quadrivalent MAPS immune sera are functional against several clinical isolates of the serotypes used in the vaccine. Conclusions: This quadrivalent MAPS Shigella vaccine is immunogenicity and warrants further study.

Persistence of hepatitis B surface antibody until 7 years of age following administration of hexavalent and pentavalent vaccines in children at 2, 4, 6, and 18 months

Thailand incorporated the hepatitis B (HepB) vaccine into the infant combination vaccine known as pentavalent wP-containing vaccines (DTwP-HB-Hib) and hexavalent aP-containing vaccines (DTaP-IPV-HB-Hib). We followed healthy children from the clinical trial (ClinicalTrials.gov NCT02408926) in which children were randomly assigned to receive either pentavalent or hexavalent vaccines for their primary series (administered at 2, 4, and 6 months) and first booster vaccination (at 18 months), following the monovalent HepB vaccine at birth. Blood samples were collected to evaluate the persistence of hepatitis B surface antibody (anti-HBs) at 3, 4, 5, 6 and 7 years of age. The results showed that at 7 years of age, a higher percentage of children in the hexavalent group maintained anti-HBs levels ≥ 10 mIU/mL compared to those in the pentavalent group (86.9 % vs. 59.7 %). This study showed good persistence of anti-HBs among hexavalent-vaccinated children 5.5 years after the last dose of the HepB vaccine.

Indirect effectiveness of COVID-19 vaccines in the pre-omicron and omicron periods: A nation-wide test-negative case-control study in Brazil

ObjectivesMass COVID-19 immunization campaigns altered the pandemic's progress by protecting the vaccine recipient and reducing transmission. However, evidence for indirect vaccine effectiveness (IVE) is limited due to the difficulties of ascertaining this type of protection. MethodsUsing linked national Brazilian databases, we adapted the test-negative design to evaluate the IVE against symptomatic infection. We analyzed data from January 1 to December 1, 2021 (pre-omicron) and January 1 to April 30, 2022 (omicron BA.1 and BA.2). We compared the probability of testing positive across various levels of second ancestral-strain monovalent COVID-19 vaccine dose coverage, including only unvaccinated individuals in the main analysis and both vaccinated and unvaccinated individuals in additional analyses. Sensitivity analysis focused on children younger than 12 years who did not have access to COVID-19 vaccines during the pre-omicron period. ResultsWe included 11,039,315 unvaccinated individuals tested during the pre-omicron study period. IVE was minimal until 30% vaccination coverage (<10%), then it followed a dose-dependent pattern, peaking at 37.7 (95% confidence interval 32-42.8) at 70% coverage. For children younger than 12 years, IVE peaked at 59.8% (95% confidence interval 52.7-65.9) at 70% coverage. During the omicron period, IVE remained constant at about 5% across all comparisons. ConclusionsOur findings confirm that high vaccination coverage using vaccines that prevent infection indirectly protects the community. However, IVE was substantially higher during the pre-omicron period.