Table.
Vaccine efficacy against B.1.1.7 and non-B.1.1.7 variants
| Cases* | ChAdOx1 nCoV-19 vaccine (n=4244) | Control vaccine (n=4290) | ChAdOx1 nCoV-19 vaccine efficacy (95% CI) | |
|---|---|---|---|---|
| Primary symptomatic COVID-19 | ||||
| B.1.1.7 | 52 (19%) | 12 | 40 | 70·4% (43·6 to 84·5) |
| Other variants | 95 (35%) | 15 | 80 | 81·5% (67·9 to 89·4) |
| No sequence result† | 30 (11%) | 5 | 25 | 80·2% (48·3 to 92·4) |
| Not sequenced‡ | 92 (34%) | 27 | 65 | 59·1% (36·0 to 73·9) |
| Total cases | 269 | 59 | 210 | 72·3% (63·1 to 79·3) |
| Asymptomatic or unknown infection | ||||
| B.1.1.7 | 19 (9%) | 8 | 11 | 28·9% (−77·1 to 71·4) |
| Other variants | 34 (16%) | 8 | 26 | 69·7% (33·0 to 86·3) |
| No sequence result† | 64 (31%) | 36 | 28 | −27·0% (−108·1 to 22·5) |
| Not sequenced‡ | 92 (44%) | 45 | 47 | 5·6% (−42·3 to 37·3) |
| Total cases | 209 | 97 | 112 | 14·6% (−12·1 to 34·9) |
| Any NAAT positive infection§ | ||||
| B.1.1.7 | 75 (14%) | 21 | 54 | 61·7% (36·7 to 76·9) |
| Other variants | 144 (28%) | 27 | 117 | 77·3% (65·4 to 85·0) |
| No sequence result† | 101 (19%) | 44 | 57 | 23·7% (−13·0 to 48·5) |
| Not sequenced‡ | 200 (38%) | 81 | 119 | 32·9% (11·0 to 49·5) |
| Total cases | 520 | 173 | 347 | 50·9% (41·0 to 59·0) |
Data include SD/SD and LD/SD seronegative efficacy cohorts only. NAAT=nucleic acid amplification test. SD=standard dose. LD=low dose.
*
Data in this column are n (%) or n.
†
No viable sequence obtained or unprocessed due to cycle threshold >30.
‡
Sample did not enter sequencing pipeline, was destroyed, or sequencing results are yet to be obtained.
§
Includes primary symptomatic cases, non-primary symptomatic cases (those with other symptoms such as nausea or diarrhoea; not shown separately), asymptomatic cases, and cases for which symptoms were unknown.