Adi Stern, Tel-Aviv University. Title: Evidence for vaccine breakthrough by coronavirus variants of concern in particular time windows post vaccination. Abstract: The BNT162b2 mRNA vaccine is highly effective against SARS-CoV-2. However, apprehension exists that variants of concerns (VOCs) may surmount vaccine protection, following evidence showing reduced neutralization of VOCs B.1.1.7 and B.1.351, and others, in laboratory assays. We performed a matched cohort study to examine the distribution of VOCs in infections of vaccinees, and hypothesized that if vaccine effectiveness against a VOC is reduced, its proportion among breakthrough cases would be higher than in unvaccinated controls. We showed that vaccinees who tested positive at least a week after the second dose, were disproportionally infected with B.1.351, compared with controls. Those who tested positive between two weeks after the first dose and a week after the second dose, were disproportionally infected by B.1.1.7, suggesting reduced vaccine effectiveness against both VOCs at particular time windows. Our results emphasize the importance of rigorously tracking viral variants, and of increasing vaccination to prevent the spread of VOCs. YouTube and Slides

Jun 17 Chantal Darquenne, University of California, San Diego. Title: The fate of inhaled aerosols in health and disease. YouTube and Slides