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. 2022 Apr 18;22(7):990–1001. doi: 10.1016/S1473-3099(22)00144-X

Table 5.

Vaccine efficacy of two doses of SCB-2019 in participants with evidence of previous exposure to SARS-CoV-2 from 14 days post-dose 2

SCB-2019 (n=6706)
Placebo (n=6683)
Vaccine efficacy (95% CI)*
Number of individuals at risk Cumulative follow-up in person-years Number of individuals with event Number of individuals at risk Cumulative follow-up in person-years Number of individuals with event
Any severity rtPCR-confirmed COVID-19 6195 551·0 11 6147 537·8 30 64·2% (26·5 to 83·8)
Moderate-to-severe rtPCR-confirmed COVID-19 6195 551·0 1 6147 537·8 3 67·5% (−305 to 99·4)
Severe rtPCR-confirmed COVID-19 6195 551·0 0 6147 537·8 0

Vaccine efficacy endpoints (from 14 days after the first dose up to second dose) of the cutoff data for efficacy analysis. Participants included in the analysis population were considered at risk only if they were followed ≥14 days after the first or second dose in the corresponding vaccine efficacy analysis period.

*

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

Cumulative follow-up was calculated for all participants at risk within each group using the time period from 1 day after the first dose to analysis cutoff on Aug 10, 2021.