Safety and Immunogenicity of a Third Dose of SARS-CoV-2 mRNA Vaccine — An Interim Analysis (preprint)

Waning immunity after two SARS-CoV-2 mRNA vaccinations and the emergence of variants precipitated the need for a third dose of vaccine. We evaluated early safety and immunogenicity after a third mRNA vaccination in adults who received the mRNA-1273 primary series in the Phase 1 trial approximately 9 to 10 months earlier. The booster vaccine formulations included 100 mcg of mRNA-1273, 50 mcg of mRNA-1273.351 that encodes Beta variant spike protein, and bivalent vaccine of 25 mcg each of mRNA-1273 and mRNA-1273.351. A third dose of mRNA vaccine appeared safe with acceptable reactogenicity. Vaccination induced rapid increases in binding and neutralizing antibody titers to D614G, Beta, and Delta variants that were similar or greater than peak responses after the second dose. Spike-specific CD4+ and CD8+ T cells increased to similar levels as after the second dose. A third mRNA vaccination was well tolerated and generated robust humoral and T cell responses. ClinicalTrials.gov numbers NCT04283461 (mRNA-1273 Phase 1) and NCT04785144 (mRNA-1273.351 Phase 1)

Covid on Campus: An Empirical Analysis of Covid Infection Rates at US Colleges and Universities (preprint)

We provide an empirical analysis of the determinants of cumulative Covid infection rates at over 1,100 US colleges and universities during the 2020-21 academic year. We propose a simple theoretical framework in which financially constrained educational institutions face a trade-off between educational quality and the reduction of Covid infection risks. This framework suggests that an institution’s equilibrium Covid infection rate will be determined by a set of exogenous variables describing its finances, demographics, selectivity, governance, and location. We find that cumulative campus infection rates are higher at wealthier institutions, measured by higher endowments per student or higher tuition rates. Institutions with lower enrollment yields in admissions also have higher Covid infection rates, perhaps reflecting the greater influence of student preferences on decision making at these institutions. Economies of scale in Covid mitigation emerge gradually over the course of the year. Finally, we find that infection rates are higher at public institutions and that this effect is fully explained by higher infection rates at public institutions in states with Republican governors.

COVID on Campus: An Empirical Analysis of COVID Infection Rates at US Colleges and Universities (preprint)

We provide an empirical analysis of the determinants of cumulative COVID infection rates at over 1,100 US colleges and universities during the 2020-21 academic year. We propose a simple theoretical framework in which financially constrained educational institutions face a trade-off between educational quality and the reduction of COVID infection risks. This framework suggests that an institution’s equilibrium COVID infection rate will be determined by a set of exogenous variables describing its finances, demographics, selectivity, governance, and location. We find that cumulative campus infection rates are higher at wealthier institutions, measured by higher endowments per student or higher tuition rates. Institutions with lower enrollment yields in admissions also have higher COVID infection rates, perhaps reflecting the greater influence of student preferences on decision making at these institutions. Economies of scale in COVID mitigation emerge gradually over the course of the year. Finally, we find that infection rates are higher at public institutions and that this effect is fully explained by higher infection rates at public institutions in states with Republican governors.