Real-word immunogenicity of a recombinant subunit COVID-19 vaccine and effectiveness against omicron infection: a prospective, multi-centre, longitudinal cohort study in Alzheimer's disease patients (preprint)

Introduction Vaccination is an essential strategy against COVID-19 in the current era of emerging variants. This study evaluates the real-world immunogenicity and effectiveness of the recombinant subunit COVID-19 vaccine (Zifivax) in Alzheimer's disease (AD) patients.Methods 249 AD patients were enrolled in a multicentre, longitudinal cohort study. Levels of RBD-IgG, neutralization antibody activity, and cytokines were identified to evaluate the immune responses. Clinical outcomes were assessed within one month following Omicron infection..Results Following three doses, the vaccine induced a robust immune response, elevating neutralizing antibodies and activating T-cells. AD patients exhibited significantly higher humoral immune responses compared to unvaccinated counterparts. Following Omicron infection, unvaccinated patients experienced higher levels of Th1/Th2-type cytokines than vaccinated individuals. Vaccination correlated with increased survival rates and extended survival times after infection..Discussion The findings highlight the vaccine's efficacy in reducing severe illness, and preventing death in AD patients facing Omicron infection.

Molecular dynamics analysis of fast-spreading severe acute respiratory syndrome coronavirus 2 variants and their effects in the interaction with human angiotensin-converting enzyme 2 (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is evolving with mutations in the Spike protein, especially in the receptor-binding domain (RBD). The failure of public health measures to contain the spread of the disease in many countries has given rise to novel viral variants with increased transmissibility. However, key questions about how quickly the variants can spread and whether they can cause a more severe disease remain unclear. Herein, we performed a structural investigation using molecular dynamics simulations and determined dissociation constant (KD) values using surface plasmon resonance (SPR) assays of three fast-spreading SARS-CoV-2 variants, Alpha, Beta and Gamma ones, as well as genetic factors in the host cells that may be related to the viral infection. Our results suggest that the SARS-CoV-2 variants facilitate their entry into the host cell by moderately increased binding affinities to the human ACE2 receptor, different torsions in hACE2 mediated by RBD variants, and an increased Spike exposure time to proteolytic enzymes. We also found that other host cell aspects, such as gene and isoform expression of key genes for the infection (ACE2, FURIN and TMPRSS2), may have few contributions to the SARS-CoV-2 variants infectivity. In summary, we concluded that a combination of viral and host cell factors allows SARS-CoV-2 variants to increase their abilities to spread faster than wild-type.