Table 4.
Efficacy against SARS-CoV-2 more than 21 days after the first standard dose in seronegative participants who received only standard doses
| Total number of cases |
ChAdOx1 nCoV-19 |
Control |
Vaccine efficacy (95% CI) | |||
|---|---|---|---|---|---|---|
| n/N (%) | Incidence per 1000 person-years (person-days of follow-up) | n/N (%) | Incidence per 1000 person-years (person-days of follow-up) | |||
| COV002 (UK) | 90 | 28/3060 (0·9%) | 35·4 (288 955) | 62/3064 (2·0%) | 78·5 (288 395) | 55·0% (29·7 to 71·1) |
| COV003 (Brazil) | 102 | 23/3247 (0·7%) | 46·7 (179 743) | 79/3233 (2·4%) | 162·4 (177 693) | 71·2% (54·2 to 81·9) |
| Primary symptomatic COVID-19* | 192 | 51/6307 (0·8%) | 39·7 (468 698) | 141/6297 (2·2%) | 110·5 (466 088) | 64·1% (50·5 to 73·9) |
| Other non-primary symptomatic COVID-19† | 21 | 12/6307 (0·2%) | 9·4 (468 698) | 9/6297 (0·1%) | 7·1 (466 088) | −32·8% (−214·8 to 44·0)‡ |
| Any symptomatic COVID-19 | 213 | 63/6307 (1·0%) | 49·1 (468 698) | 150/6297 (2·4%) | 117·5 (466 088) | 58·3% (44·0 to 68·9) |
| Asymptomatic or symptoms unknown (COV002) | 71 | 34/2751 (1·2%) | 46·8 (265 142) | 37/2760 (1·3%) | 51·0 (264 994) | 7·8% (−46·7 to 42·1) |
| Any NAAT-positive swab | 291 | 102/6307 (1·6%) | 79·5 (468 698) | 189/6297 (3·0%) | 148·1 (466 088) | 46·3% (31·8 to 57·8) |
Vaccine efficacy was calculated from the robust Poisson model. The first-standard-dose efficacy population includes participants seronegative at baseline who received only standard dose vaccines or were in the corresponding control group, and remained on study 22 days after their first dose without having had a previous virologically confirmed SARS-CoV-2 infection. In addition, for groups in COV002, only efficacy groups (ie, groups 4, 6, 9, and 10) are included. SARS-CoV-2=severe acute respiratory syndrome coronavirus 2. NAAT=nucleic acid amplification test.
NAAT-positive swab plus at least one of cough, shortness of breath, fever higher than 37·8°C, anosmia, or ageusia.
Other non-primary symptomatic COVID-19 disease includes cases that have symptoms other than the five main symptoms required for inclusion in the primary analysis (eg, a participant who has diarrhoea and malaise but no fever, cough, shortness of breath, anosmia, or ageusia).
Vaccine efficacy was calculated from a reduced robust Poisson model (excluding the age group category due to the full model failing to converge). Participants with a low-dose prime were excluded.