Volume 28, Number 3—March 2022
Research
Effectiveness of 3 COVID-19 Vaccines in Preventing SARS-CoV-2 Infections, January–May 2021, Aragon, Spain
, Héctor López-Mendoza, Armando Chaure-Pardos, Alberto Vergara-Ugarriza, and Joaquín Guimbao-Bescós
Table 3
Effectiveness of Pfizer-BioNTech, Moderna, and Oxford-AstraZeneca coronavirus disease vaccines in preventing confirmed SARS-CoV-2 infection, Aragon, Spain, January–May 2021*
| Vaccination status | Person-days, total (average) | Population | SARS-CoV-2 infections | IR† | Unadj HR‡ | Adj HR‡ | Unadj VE,§ % (95% CI) | Adj VE, § % (95% CI) |
|---|---|---|---|---|---|---|---|---|
| Pfizer-BioNTech | ||||||||
| 1 dose | 3,750,582 (15.5) | 242,142 | 463 | 0.86 | 0.77 | 0.79 | 23.5 (16.0–30.3) | 20.8 (11.6–29.0) |
| 2 doses |
8,705,040 (41.0) |
212,419 |
280 |
0.23 |
0.24 |
0.30 |
76.1 (73.1–78.8) |
70.0 (65.3–74.1) |
| Moderna | ||||||||
| 1 dose | 633,821 (19.5) | 32,522 | 28 | 0.31 | 0.31 | 0.47 | 69.2 (55.4–78.8) | 52.8 (30.7–67.8) |
| 2 doses |
592,877 (37.9) |
15,660 |
18 |
0.21 |
0.22 |
0.30 |
78.4 (65.6–86.4) |
70.3 (52.2–81.5) |
| Oxford-AstraZeneca | ||||||||
| 1 dose |
2,932,610 (30.1) |
97,492 |
230 |
0.55 |
0.56 |
0.60 |
43.7 (35.7–50.7) |
40.3 (31.8–47.7) |
| Unvaccinated | 128,261,888 (133.0) | 592,102 | 25,767 | 1.41 | 1.00 | 1.00 | NA | NA |
*Adj, adjusted; HR, hazard ratio; IR, incidence rate; NA, not applicable; SARS-CoV-2, severe acute respiratory syndrome coronavirus; unadj, unadjusted; VE, vaccine effectiveness †Incidence rate of SARS-CoV-2 infection was measured in 1,000 person-weeks (not person-days) to make it to read the table (estimates expressed with <2 decimals. ‡HR was adjusted by age, sex, work or residence in nusing or residential homes), weekly cumulative incidence in each primary care service area, and number of SARS-CoV-2 tests administered in the previous 6 months. §Vaccine effectiveness against SARS-CoV-2 infection was calculated as 1 – HR.