Table 3. Incidence rate, hazard ratio, and vaccine effectiveness of 2 doses of mRNA-1273 in preventing SARS-CoV-2 infection by age, sex, race/ethnicity, and Delta period subgroups.
| Vaccinated (N = 927004) | Unvaccinated (N = 927004) | Hazard Ratio (95% CI) | VE % (95% CI) | |||||
|---|---|---|---|---|---|---|---|---|
| Number of cases | Incidence per 1000 person-years (95% CI) | Number of cases | Incidence per 1000 person-years (95% CI) | Unadjusted | Adjusteda | Unadjusted | Adjusteda | |
| Age at index date, years | ||||||||
| 18–44 | 3196 | 23.05 (22.26–23.86) | 7145 | 109.90 (107.38–112.48) | 0.16 (0.15–0.17) | 0.17 (0.17–0.18) | 84.0 (83.3–84.7) | 82.6 (81.7–83.5) |
| 45–64 | 2811 | 19.15 (18.46–19.88) | 6912 | 104.79 (102.35–107.29) | 0.14 (0.13–0.15) | 0.15 (0.15–0.16) | 85.9 (85.2–86.5) | 84.6 (83.8–85.4) |
| 65–74 | 1098 | 14.64 (13.80–15.53) | 1877 | 62.57 (59.81–65.47) | 0.19 (0.18–0.21) | 0.18 (0.17–0.20) | 80.8 (79.3–82.2) | 81.6 (79.9–83.1) |
| ≥75 | 580 | 13.78 (12.71–14.95) | 875 | 49.13 (45.98–52.49) | 0.24 (0.22–0.27) | 0.22 (0.20–0.25) | 75.9 (73.2–78.3) | 77.9 (75.1–80.3) |
| Sex | ||||||||
| Female | 4459 | 19.97 (19.39–20.56) | 9116 | 96.18 (94.23–98.18) | 0.17 (0.16–0.17) | 0.18 (0.17–0.18) | 83.2 (82.6–83.8) | 82.4 (81.7–83.1) |
| Male | 3226 | 18.00 (17.39–18.64) | 7693 | 91.58 (89.56–93.65) | 0.16 (0.16–0.17) | 0.17 (0.16–0.18) | 83.7 (83.0–84.4) | 83.1 (82.3–83.9) |
| Race/Ethnicity | ||||||||
| Non-Hispanic White | 2601 | 18.88 (18.16–19.62) | 6061 | 94.48 (92.13–96.89) | 0.17 (0.16–0.18) | 0.18 (0.17–0.19) | 83.2 (82.4–84.0) | 82.1 (81.1–83.0) |
| Non-Hispanic Black | 523 | 17.41 (15.98–18.97) | 1497 | 109.90 (104.47–115.61) | 0.14 (0.12–0.15) | 0.13 (0.12–0.15) | 86.2 (84.7–87.5) | 87.0 (85.5–88.4) |
| Hispanic | 3488 | 23.03 (22.28–23.81) | 7177 | 103.15 (100.79–105.57) | 0.18 (0.17–0.19) | 0.18 (0.17–0.19) | 82.1 (81.3–82.9) | 81.8(80.9–82.6) |
| Non-Hispanic Asian | 612 | 11.37 (10.50–12.31) | 940 | 52.47 (49.22–55.93) | 0.16 (0.14–0.18) | 0.17 (0.15–0.19) | 83.9 (82.1–85.6) | 83.4 (81.2–85.4) |
| Delta periodb | 319 | 20.38 (18.27–22.75) | 1973 | 146.73 (140.40–153.35) | 0.14 (0.12–0.15) | 0.13 (0.12–0.15) | 86.3 (84.6–87.9) | 86.5 (84.8–88.0) |
aAdjusted for covariates age groups (in 4 categories, and not adjusted in the age subcohort analysis), sex (not adjusted in the sex subcohort analysis), race/ethnicity (not adjusted in the race/ethnicity subcohort analysis), index date (in months), number of outpatient and virtual visits, preventive care, KPSC physician/employee status, medical center area.
bIndividuals with index dates in June 2021 were followed up to September 30, 2021.
N, sample size; CI, confidence interval; VE, vaccine effectiveness.