pneumococcal vaccine (Prevenar20 / PCV20 / PF 06482077)

A subunit vaccine protects A129 mice from death and joint swelling against lethal Chikungunya virus challenge.

Li Jiangfan J, Fang Ting T, Song Liyuan L, Qiang Li L et al.

Chikungunya virus (CHIKV) is primarily transmitted to humans through bites of infected Aedes mosquitoes, causing febrile illness as well as acute or chronic arthritis. With increasing reports in previously non-endemic regions, it poses an emerging threat to public health and a growing risk to travelers. Despite the recent approval of live-attenuated and virus-like particle-based vaccines, a safe, efficacious, and cost-effective vaccine remains urgently needed. The envelope glycoproteins E1 and E2, which play crucial roles in viral attachment and entry, are the major immunodominant structural proteins and can effectively elicit protective antibodies. We engineered mammalian cells to produce the ectodomains of the E1 and E2 glycoproteins and evaluated the protective efficacy of the resulting vaccine formulations in vivo. A two-dose vaccination regimen elicited high levels of antibodies and provided full protection against lethal challenge in A129 mice, preventing both death and joint swelling. These findings demonstrate the potential of this vaccine candidate against CHIKV and warrant its further development.

[Strategies to address vaccine hesitancy in Brazil: evidence synthesis].

Marques Ana Paula da Costa APDC, Gubert Vanessa Terezinha VT, Dias Adriano da Costa ADC, Gasparoto Antonio Luiz Dal Bello ALDB et al.

Clinical effects of third doses of mRNA COVID-19 vaccines among hemodialysis patients: a nationwide retrospective cohort study.

Cho AJin A, Jeong Seon A SA, Seo Yu Bin YB, Park Hayne Cho HC et al.

Evidence on the effectiveness of third-dose messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccination during the Omicron-dominant period in Asian hemodialysis (HD) patients remains limited. We evaluated the clinical effectiveness of a third mRNA vaccine dose against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hospitalization, and mortality in Korean HD patients. Using the Korea Disease Control and Prevention Agency-National Health Insurance Service database, we conducted a nationwide cohort study of HD patients aged ≥18 years who received two or three doses of BNT162b2 or mRNA-1273 before January 16, 2022. Study outcomes were SARS-CoV-2 infection, hospitalization, and death. Cox proportional hazards models were used to assess the associations between third-dose vaccination and clinical outcomes. Among 66,389 HD patients (mean age, 65.7 ± 12.9 years; 60.5% male), 55,125 (83.0%) received three vaccine doses and 11,264 (17.0%) received two doses. Receipt of three doses was associated with a significantly lower risk of SARS-CoV-2 infection (adjusted hazard ratio [aHR], 0.58; 95% confidence interval [CI], 0.56-0.60). Among 17,886 patients with SARS-CoV-2 infection, third-dose vaccine recipients had a lower risk of hospitalization (aHR, 0.65; 95% CI, 0.62-0.70) and 30-day mortality (aHR, 0.35; 95% CI, 0.30-0.41) compared with those who received two doses. Receipt of mRNA-1273 as the third dose was associated with lower observed risks of infection and hospitalization than receipt of BNT162b2. A third dose of an mRNA COVID-19 vaccine was associated with lower risks of SARS-CoV-2 infection, hospitalization, and mortality among HD patients during the Omicron-dominant period. These findings support the clinical importance of booster vaccination in this high-risk population.

Integrated immunoreactivity analysis of MHC-I epitopes derived from the Marburg virus glycoprotein.

Yang Yulin Y, Wang Jing J, Guan Enqi E, Wei Hengzheng H et al.

Marburg virus (MARV) is a hemorrhagic fever virus, and its glycoprotein (GP) represents an important target for vaccine research. MHC class I (MHC-I)-restricted T cell epitopes are critical for inducing cytotoxic CD8+ T cell responses. In this study, we aimed to identify MHC-I-restricted T cell epitopes derived from the MARV Angola strain GP through an integrated bioinformatics and experimental approach. We retrieved the MARV Angola strain GP sequence and divided it into 673 overlapping 9-mer peptides. By integrating five computational prediction algorithms, immunogenicity scoring tools and BLASTp conservation analysis, we screened 9-mer peptides from the MARV Angola GP. Molecular docking was performed with MHC-I structures using HPEPDOCK and molecular dynamics (MD) analysis. Bidirectional hierarchical clustering was used to analyze binding similarity across MHC-I molecules. Mutations identified in epitope regions were tested for their effect on affinity. Toxicity and allergenicity of the epitopes were predicted using dedicated tools. Finally, BALB/c and C57BL/6 mice were immunized with a DNA vaccine encoding MARV GP. IFN-γ secretion in mouse splenocytes was then measured by ELISpot, serum IgG by ELISA, and CD8+ T cell cytokine production by flow cytometry. Among 673 GP peptides, eight epitopes (GAFFLYDRI, REGDMFPFL, DMFPFLDGL, NENDCDAEL, AGLSWIPFF, NQNNLVCRL, TGWGLGGKW, SDWGVLTNL) were predicted to exhibit high-affinity MHC-I binding, strong immunogenicity, and intraspecies conservation. Bidirectional hierarchical clustering analysis, molecular docking, sequence alignment, and toxicity/allergenicity predictions suggested binding across selected alleles, structural stability, limited impact from identified mutations, and low predicted toxicity. In subsequent ELISpot validation, eight epitopes elicited strong IFN-γ responses. In addition, serum from GP-immunized mice contained IgG that bound the corresponding linear peptide sequences. An integrated computational-experimental pipeline identified eight conserved, immunogenic MHC-I epitopes from MARV GP. These selected epitopes may serve as promising candidates for future vaccine design.