A dual-antigen self-amplifying RNA SARS-CoV-2 vaccine induces potent humoral and cellular immune responses and protects against SARS-CoV-2 variants through T cell-mediated immunity.

Self-amplifying RNA vaccines may induce equivalent or more potent immune responses at lower doses compared to non-replicating mRNA vaccines via amplified antigen expression. In this paper, we demonstrate that 1 µg of an LNP-formulated dual-antigen self-amplifying RNA vaccine (ZIP1642), encoding both the S-RBD and N antigen, elicits considerably higher neutralizing antibody titers against Wuhan-like Beta B.1.351 and Delta B.1.617.2 SARS-CoV-2 variants compared to those of convalescent patients. In addition, ZIP1642 vaccination in mice expanded both S- and N-specific CD3+CD4+ and CD3+CD8+ T cells and caused a Th1 shifted cytokine response. We demonstrate that the induction of such dual antigen-targeted cell-mediated immune response may provide better protection against variants displaying highly mutated Spike proteins, as infectious viral loads of both Wuhan-like and Beta variants were decreased after challenge of ZIP1642 vaccinated hamsters. Supported by these results, we encourage redirecting focus toward the induction of multiple antigen-targeted cell-mediated immunity in addition to neutralizing antibody responses to bypass waning antibody responses and attenuate infectious breakthrough and disease severity of future SARS-CoV-2 variants.

Covid-19 Social Distancing Interventions by Statutory Mandate and Their Observational Correlation to Mortality in the United States and Europe.

PURPOSE: Evaluate the correlation between statutory social distancing interventions and Covid-19 mortality independently in both the United States and Europe. The study is presented as a potential methodology to evaluate the effectiveness of statutory social distancing policy. PATIENTS AND METHODS: Twenty-seven states in the United States and, separately, 12 European countries were selected which had clearly defined and dated establishment of statewide or national mandates for social distancing measures from the Institute for Health Metrics and Evaluation (IHME) data. Mandated social distancing measures considered in this study include: School closures, Prohibition on mass gatherings, business closures, stay at home orders, severe travel restrictions, and closure of non-essential businesses. The state/country Covid-19 peak mortality rate (PMR) was defined as the initial averaged normalized maximum during which social distancing mandates were in effect. Mandate-days were defined as the total days legislative mandates were in place to the PMR. RESULTS: The normalized peak mortality rate in the US and in Europe did not demonstrate a statistically significant correlation to the total mandate days (R-squared=0.053, p=0.246, R-squared=2.4E-06, p=0.996). A significant correlation was found between normalized mortality rate and state/country population density (R-squared=0.524, p=0.00002,R-squared=0.397, p=0.0281). DISCUSSION: The analysis appears to suggest no mandate effective reduction in Covid-19 mortality rate to its defined initial peak when interpreting their mean-effect. A strong correlation to population density suggests human interaction frequency does affect the peak mortality rate.