Table 3.

Protective efficacy against any severity of COVID-19 due to previous SARS-CoV-2 exposure in placebo recipients, by country

	Predominant variants		SARS-CoV-2-naive patients		SARS-CoV-2-exposed patients		Protective efficacy (95% CI)*
	Before the study†	During the study	Cumulative follow-up in person-years‡	Number of individuals with an event	Cumulative follow-up in person-years‡	Number of individuals with an event
Belgium	Alpha	Alpha	65·0	4	8·7	0	100% (−1032 to 100)
Brazil	Gamma	Gamma (57%); delta (13%)	290·7	53	128·1	3	87·2% (60·4 to 97·4)
Colombia	Alpha, gamma, mu, lambda	Mu (49%); gamma (10%); B.1.623 (7%); lambda (6%)	199·5	123	168·4	22	78·8% (66·5 to 87·2)
Philippines	Alpha	Delta 29%); beta (15%); alpha (14%); theta (3%)	486·8	132	847·3	38	83·5% (76·1 to 88·8)
South Africa	Beta	Delta (61%); beta (7%)	46·9	41	40·0	2	94·3% (78·0 to 99·3)
Overall	..	..	1088·9	353	1192·5	65	83·2% (78·0 to 87·3)

^*95% CI for protective efficacy was calculated using Clopper-Pearson method, which was based on conditional binomial distribution.

^†Sourced from Nextstrain and the Philippines Genome center .

^‡Cumulative follow-up was calculated in all participants at risk within each group using the time period from 14 days after the first dose to analysis cutoff on Aug 10, 2021.