Table 3. Odds ratio of COVID-19 vaccination by time since vaccination to symptom onset among participants receiving one dose only of 2-dose COVID-19 vaccines in the primary care/outpatient I-MOVE-COVID-19 vaccine effectiveness study, Europe, December 2020–May 2021.
| Main analysis (nine study sites) | |||
|---|---|---|---|
| Analysis type and one dose vaccination status | Cases / controls |
OR
(95% CI)a |
AOR (95% CI)b |
| Any COVID-19 vaccine (except Janssen (Ad26.COV2-S (recombinant), Janssen-Cilag International NV, Beerse, Belgium) | |||
| Unvaccinated | 508/2,358 | Ref | Ref |
| 1–4 daysc | 36/243 | 0.89 (0.60–1.31) | 0.86 (0.58–1.27) |
| 5–13 daysd | 59/503 | 0.64 (0.47–0.89) | 0.63 (0.45–0.87) |
| ≥ 14 dayse | 52/866 | 0.38 (0.26–0.55) | 0.38 (0.26–0.55) |
| Comirnaty (BNT162b2, BioNTech-Pfizer, Mainz, Germany/New York, United States) vaccine | |||
| Unvaccinated | 506/2,352 | Ref | Ref |
| 1–4 daysc | 27/169 | 0.92 (0.59–1.43) | 0.88 (0.56–1.39) |
| 5–13 daysd | 50/366 | 0.70 (0.50–0.99) | 0.68 (0.48–0.97) |
| ≥ 14 dayse | 30/433 | 0.40 (0.26–0.62) | 0.39 (0.25–0.61) |
| Vaxzevria (ChAdOx1/nCoV-19, AstraZeneca, Cambridge, United Kingdom) vaccine | |||
| Unvaccinated | 505/2,345 | Ref | Ref |
| 1–4 daysc | 6/56 | 0.71 (0.29–1.74) | 0.70 (0.28–1.73) |
| 5–13 daysd | 3/102 | Sample size too small | Sample size too small |
| ≥ 14 dayse | 18/342 | 0.32 (0.17–0.59) | 0.32 (0.17–0.61) |
AOR: adjusted odds ratio; CI: confidence interval; COVID-19: coronavirus disease; OR: odds ratio; Ref: reference; VE: vaccine effectiveness.
a Adjusted by study site, month of swab (due to low numbers December and January were one category).
b Adjusted by study site, month of swab (due to low numbers December and January were one category), 10-year age group, sex. Due to substantial missing data on chronic conditions from one study site, the estimates were not adjusted by chronic condition.
c First dose of 2-dose COVID-19 vaccine received 1–4 days before onset, patients with unknown doses or two doses excluded.
d First dose of 2-dose COVID-19 vaccine received 5–13 days before onset, patients with unknown doses or two doses excluded.
e First dose of 2-dose COVID-19 vaccine received ≥ 14 days before onset, patients with unknown doses or two doses excluded.