Table 2.

Incidence of Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Adjusted Estimates of Vaccine Efficacy by Group and Vaccine Receipt^a

Group	Exposure Time Period	Participants Contributing Person-Time, No.	Incident Infections, No.	Person- Years	Incidence Rate Per 100 Person-Years (95% CI)	Adjusted Estimate of Vaccine Efficacy Against SARS-CoV-2 Infection (95% CI), %b
Immediate	Before vaccination	521	0	4.8	0.0 (.0–77.3)	NA
	After 1 dose	573	13	43.8	29.7 (15.8–50.7)	−6.8 (−138.3, to 52.2)
	After 2 doses	489	11	89.9	12.2 (6.1–21.9)	52.6 (−14.1 to 80.3)
SoC	Unvaccinated	531	24	75.6	31.8 (20.3–47.2)	NA
Vaccine declined	Unvaccinated	311	45	50.2	89.6 (65.4–119.9)	NA

Abbreviations: CI, confidence interval; NA, not applicable; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; SoC, standard of care.

^aThis analysis included the subset of participants without SARS-CoV-2 at baseline, from the full analysis set with polymerase chain reaction data; they were censored at outside vaccination.

^bCox proportional hazard models of incident SARS­CoV­2 infection event on the calendar time scale, stratified by site and adjusted for factors associated with outside vaccination or SARS-CoV-2 infection absent vaccination: sex, residence, team sport participation at baseline, mask wearing at baseline, and SARS­CoV­2 exposure risk score.