Real world SARS-COV-2 vaccine effectiveness in a Miami academic institution

To assess the effectiveness of messenger RNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) in preventing emergency department (ED) presentations for acute respiratory illness. We conducted a retrospective study assessing adult presentations (age ≥ 18) to the University of Miami Hospital's ED from January 1st through August 25th, 2021, with a SARS-COV-2 PCR test and acute respiratory infection symptoms. Vaccine effectiveness was calculated using a test-negative design. Both univariable and multivariable (adjusted for age, gender, race, insurance status, imputed body mass index [BMI], vaccine type, week of presentation) regression analyses were conducted for the full cohort and subgroups. The cohort consisted of 13,203 ED presentations—3134 (23.7%) fully vaccinated and SARS-COV-2 negative, 108 (0.8%) fully vaccinated and SARS-COV-2 positive, 8817 (66.8%) unvaccinated and SARS-COV-2 negative, and 1144 (8.7%) unvaccinated and SARS-COV-2 positive. Unadjusted vaccination effectiveness was 73.4% (95% confidence interval: 67.5%,78.3%) and, after adjustment, 73.8% (66.2%,79.7%). The Moderna vaccine's effectiveness was numerically higher (unadjusted: 78.2% [68.8%, 84.7%]; adjusted: 78.0% [68.1%, 84.9%]) than the Pfizer vaccine's (unadjusted: 70.8% [62.9%, 76.9%]; adjusted: 73.9% [66.3%,79.8%]). We found a significant difference in adjusted vaccine effectiveness across categories was BMI (p < 0.001)—BMI