Table 3.
Primary and key secondary vaccine efficacy endpoints in per-protocol population
|
SCB-2019 (n=6251) |
Placebo (n=6104) |
Vaccine efficacy rate (CI)* | ||||||
|---|---|---|---|---|---|---|---|---|
| Number at risk | Cumulative follow-up in person-years† | Number with event | Number at risk | Cumulative follow-up in person-years† | Number with event | |||
| Vaccine efficacy in SARS-CoV-2-naive participants | ||||||||
| Any severity RT-PCR-confirmed COVID-19 | 5935 | 517·3 | 52 | 5806 | 506·1 | 155 | 67·2% (95·72% CI 54·3 to 76·8) | |
| Moderate-to-severe RT-PCR-confirmed COVID-19 | 5935 | 517·3 | 6 | 5806 | 506·1 | 36 | 83·7% (97·86% CI 55·9 to 95·4) | |
| Severe RT-PCR-confirmed COVID-19 | 5935 | 517·3 | 0 | 5806 | 506·1 | 8‡ | 100% (97·86% CI 25·3 to 100·0) | |
| Any severity RT-PCR-confirmed COVID-19 associated with admission to hospital | 5935 | 517·3 | 0 | 5806 | 506·1 | 8‡ | 100% (42·7 to 100·0) | |
| Vaccine efficacy endpoints in SARS-CoV-2-naive participants with any severity COVID-19 against specific variants§ | ||||||||
| Delta variant (B.1.617.2) | 5935 | 517·3 | 10 | 5806 | 506·1 | 46 | 78·7% (57·3 to 90·4) | |
| Gamma variant (P.1) | 5935 | 517·3 | 1 | 5806 | 506·1 | 12 | 91·8% (44·9 to 99·8) | |
| Mu variant (B.1.621) | 5935 | 517·3 | 11 | 5806 | 506·1 | 26 | 58·6% (13·3 to 81·5) | |
| Other variants or not identified¶ | 5935 | 517·3 | 13 | 5806 | 506·1 | 27 | 55·0% (24·9 to 73·8) | |
| Vaccine efficacy in SARS-CoV-2-naive participants at low risk and high risk because of absence or presence of underlying comorbidities | ||||||||
| Any severity RT-PCR-confirmed COVID-19 | ||||||||
| Low | 4908 | 427·8 | 38 | 4857 | 423·3 | 117 | 67·9% (53·3 to 78·3) | |
| High | 1027 | 89·5 | 14 | 949 | 82·8 | 38 | 65·9% (35·7 to 82·9) | |
| Moderate-to-severe RT-PCR-confirmed COVID-19 | ||||||||
| Low | 4908 | 427·8 | 3 | 4857 | 423·3 | 23 | 87·1% (57·3 to 97·5) | |
| High | 1027 | 89·5 | 3 | 949 | 82·8 | 13 | 78·7% (22·3 to 96·1) | |
| Severe RT-PCR-confirmed COVID-19 | ||||||||
| Low | 4908 | 427·8 | 0 | 4857 | 423·3 | 1 | 100% (−3759 to 100·0) | |
| High | 1027 | 89·5 | 0 | 949 | 82·8 | 7 | 100% (35·8 to 100·0) | |
| Any severity RT-PCR-confirmed COVID-19 associated with admission to hospital | ||||||||
| Low | 4908 | 427·8 | 0 | 4857 | 423·3 | 2 | 100% (−427 to 100·0) | |
| High | 1027 | 89·5 | 0 | 949 | 82·8 | 6 | 100% (21·5 to 100·0) | |
| Vaccine efficacy in SARS-CoV-2-naive participants with any severity COVID-19 according to age, sex, or BMI | ||||||||
| Age 18–59 years | 5814 | 502·3 | 49 | 5679 | 489·5 | 147 | 67·5% (54·8 to 77·0) | |
| Age ≥60 years | 121 | 15·0 | 3 | 127 | 16·7 | 8 | 58·4% (−73·4 to 92·9) | |
| Female | 2703 | 229·2 | 25 | 2569 | 217·0 | 72 | 67·1% (47·5 to 80·0) | |
| Male | 3232 | 288·1 | 27 | 3237 | 289·1 | 83 | 67·4% (49·1 to 79·7) | |
| BMI <30 | 5054 | 444·0 | 42 | 4987 | 438·8 | 128 | 67·6% (53·7 to 77·7) | |
| BMI ≥30 | 880 | 73·3 | 10 | 817 | 67·2 | 27 | 66·0% (27·6 to 85·3) | |
BMI=body mass index.
CI for vaccine efficacy, calculated using the Clopper-Pearson method based on conditional binomial distribution, was 95% CI unless shown otherwise.
Cumulative follow-up calculated among all participants at risk within each group, using the time period from 14 days after the second dose to the analysis cutoff on Aug 10, 2021.
Of eight severe cases of COVID-19, seven were admitted to hospital; of eight participants admitted to hospital, seven had severe COVID-19 and one had moderate COVID-19 with pneumonia.
Only calculated for variants for which a sufficient number of cases were detected to provide meaningful analysis.
Includes cases where variant was not identified or cases were too few for variant-specific analysis (alpha, beta, B.1.623, lambda, theta, etc).