Table 3.
Vaccine effectiveness of two doses of mRNA-1273 against admission to hospital with covid-19 due to delta, non-delta, or unidentified variants
| Variant | No | No (%) test positive | No (%) test negative | Odds ratio (95% CI) | Vaccine effectiveness (95% CI) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Vaccinated | Unvaccinated | Vaccinated | Unvaccinated | Unadjusted | Adjusted* | Unadjusted (%) | Adjusted* (%) | |||||
| Delta | 846 | 5 (4) | 136 (96) | 365 (51.8) | 340 (48.2) | 0.03 (0.01 to 0.07) | 0.03 (0.01 to 0.07) | 97.4 (92.8 to 99.0) | 97.5 (92.7 to 99.2) | |||
| Non-delta† | 1038 | 0 (0) | 173 (100) | 306 (35.4) | 559 (64.6) | NE | NE | NE | NE | |||
| Unidentified‡ | 588 | 7 (7) | 91 (93) | 227 (46.3) | 263 (53.7) | 0.05 (0.02 to 0.13) | 0.03 (0.01 to 0.11) | 94.8 (86.8 to 98.0) | 96.6 (89.5 to 98.9) | |||
This subgroup analysis included test positive cases admitted to hospital and their matched test negative controls.
NE=not estimable.
Model for delta variant adjusted for smoking, Charlson comorbidity score, frailty index, liver disease, pregnancy, history of SARS-CoV-2 infection, number of outpatient and virtual visits, preventive care, medical center area, month of specimen collection, and specimen type; model for unidentified variants adjusted for body mass index, smoking, Charlson comorbidity score, frailty index, pregnancy, history of SARS-CoV-2 infection, number of outpatient and virtual visits, number of emergency department visits, preventive care, medical center area, month of specimen collection, and specimen type.
Non-delta variants included alpha, epsilon, gamma, iota, mu, and other (beta, eta, kappa, and other variants).
Unidentified variants were those for which whole genome sequencing failed.