Table 3. Primary End Point and Key Supportive Efficacy Analyses in the Full Preexposure Analysis Set.^*.

First Case of SARS-CoV-2 RT-PCR–Positive Symptomatic Illness	Primary Analysis				Median 6-Mo Follow-up†
	AZD7442 (N=3441)	Placebo (N=1731)	Relative Risk Reduction % (95% CI)	P Value	AZD7442 (N=3441)	Placebo (N=1731)	Relative Risk Reduction % (95% CI)
	no. of participants (%)				no. of participants (%)
Primary end point: first case of illness, with data censored at unblinding or receipt of Covid-19 vaccine	8 (0.2)	17 (1.0)	76.7 (46.0–90.0)	<0.001	11 (0.3)	31 (1.8)	82.8 (65.8–91.4)
Key supportive analyses
First case of illness, regardless of unblinding or receipt of Covid-19 vaccine	10 (0.3)	22 (1.3)	77.3 (52.0–89.3)	<0.001	20 (0.6)	44 (2.5)	77.4 (61.7–86.7)
First case of illness, including all deaths, with data censored at unblinding or receipt of Covid-19 vaccine	12 (0.3)	19 (1.1)	68.8 (35.6–84.9)	0.002	18 (0.5)	36 (2.1)	75.8 (57.3–86.2)

^*The full preexposure analysis set consisted of all the participants who had undergone randomization, received at least one injection of AZD7442 or placebo, and did not have RT-PCR–confirmed SARS-CoV-2 infection at baseline. Estimates were based on a Poisson regression with robust variance. The model included trial group (AZD7442 or placebo) and age at informed consent (≥60 years or <60 years), with the log of the follow-up time as an offset. Unadjusted relative risk reductions (95% CI) for the primary end point were the same as the adjusted relative risk reductions for both the primary analysis and the median 6-month follow-up. An estimated relative risk reduction greater than 0 favored AZD7442, with a P value of less than 0.05 indicating statistical significance.

^†This analysis was not prespecified in the trial protocol, so P values were not calculated.