ABSTRACT
Background Cytomegalovirus (CMV) seropositivity has a significant immunomodulating over the life course, both with respect to responses to infections and responses to vaccines. For example, influenza vaccine response is known from multivariate analyses to be reduced by CMV seropositivity in elderly individuals. In patients with COVID-19, evidence suggests there are interactions between SARS-CoV-2 and CMV. CMV seropositives may have more severe COVID disease, and patients recovering from COVID often reactivate latent CMV, leading to end-organ CMV disease. This study aimed to test two hypotheses: 1) that vectored vaccines based on attenuated arenaviruses demonstrate equivalent immunogenicity to adjuvanted protein subunit spike (S) vaccines in a guinea pig vaccine model;2) that CMV seropositivity impacts the immune response to S protein-based vaccines. Method Guinea pigs (n=3 per group) were vaccinated with a 2-dose series of an attenuated arenavirus (Pichinde virus) S protein-vectored vaccine by intranasal (IN;n=4) or intramuscular (IM) route at a dose of 1x10