Answer Happy

A recently published study assessed the efficacy of a SARS-CoV-2 vaccine on preventing symptomatic COVID-19 disease (N Engl J Med 2021;384:403-416). Participants in this study were randomly assigned to either receiving 2 doses of the Moderna vaccine 4 weeks apart or 2 doses of a placebo given 4 weeks apart. Of 14,134 persons assigned to the vaccine group who were SARS-CoV-2 uninfected at baseline and who received both vaccine doses, 11 persons developed symptomatic COVID-19 disease. Among 14,073 persons who were SARS- COV-2 uninfected at baseline and received both placebo doses, 185 developed symptomatic COVID-19 disease. 1. List the independent variable in this study: 2. The study design is best described as a (Highlight and/or bold the one best answer): Cross-sectional study Cohort study Case-control study Clinical trial 3. Draw a 2 X 2 contingency table demonstrating the association between vaccine receipt (active vaccine vs placebo) and symptomatic COVID-19 disease in this study. For full credit, the table must be labeled correctly and all internal boxes and marginal totals must be filled appropriately. Label: Label: Label: Label: