TABLE 1.
| Variant | Vaccine | Design and setting | Key outcomes | Vaccine effectiveness, % (95% CI) | Reference |
|---|---|---|---|---|---|
| Alpha | BNT162b2 | Israel; ≥7 days post-dose 2, up to 80% isolates during study period were alpha | PCR-confirmed documented infection | 92 (88 to 95) | 146 |
| PCR-confirmed symptomatic COVID-19 | 94 (87 to 98) | ||||
| Hospitalization due to COVID-19 | 87 (55 to 100) | ||||
| Severe COVID-19 | 92 (75 to 100) | ||||
| Israel; ≥7 days post-dose 2, during alpha-dominant period; HCPs | PCR-confirmed infection | 94.5 (82.6 to 98.2) | 147 | ||
| PCR-confirmed symptomatic infection | 97.0 (72.0 to 99.7) | ||||
| England; ≥14 days post-dose 2 | PCR-confirmed symptomatic COVID-19 caused by alphab | 93.7 (91.6 to 95.3) | 149 | ||
| Qatar, ≥14 days post-dose 2 | Any PCR-confirmed infection caused by alpha | 89.5 (85.9 to 92.3) | 150 | ||
| Severe, critical, or fatal disease caused by alpha | 100 (81.7 to 100) | ||||
| Scotland, ≥14 days post-dose 2 | PCR-confirmed infection caused by alphab | 92 (90 to 93) | 148 | ||
| Canada, ≥14 days post-dose 2 | PCR-confirmed symptomatic infection | 89 (87 to 91) | 151 | ||
| BNT162b2 and/or mRNA-1273 and/or ChAdOx1 nCoV-19c | Norway, ≥7 days post-dose 2 | PCR- or whole genome sequencing-confirmed infection by alpha or delta | 84.4 (81.8 to 86.5) | 187 | |
| mRNA-1273 | Canada, ≥14 days post-dose 2 | PCR-confirmed symptomatic infection | 91 (84 to 95) | 151 | |
| ChAdOx1 nCoV-19 | England, ≥14 days post-dose 2 | PCR-confirmed symptomatic COVID-19 caused by alphab | 74.5 (68.4 to 79.4) | 149 | |
| Scotland, ≥14 days post-dose 2 | PCR-confirmed infection caused by alphab | 73 (66 to 78) | 148 | ||
| Canada, ≥14 days post-dose 2 | PCR-confirmed symptomatic infection | 75 (−98 to 97) | 151 | ||
| Beta | BNT162b2 | Qatar, ≥14 days post-dose 2 | Any PCR-confirmed infection caused by beta | 75.0 (70.5 to 78.9) | 150 |
| Severe, critical, or fatal disease caused by beta | 100 (73.7 to 100) | ||||
| Delta | BNT162b2 | England, ≥14 days post-dose 2 | PCR-confirmed symptomatic COVID-19 caused by deltab | 88.0 (85.3 to 90.1) | 149 |
| Scotland, ≥14 days post-dose 2 | PCR-confirmed infection caused by deltab | 79 (75 to 82) | 148 | ||
| UK, ≥14 days post-dose 2, during delta-dominant period | PCR-confirmed infection | 80 (77 to 83) | 152 | ||
| Canada, ≥14 days post-dose 2 | PCR-confirmed symptomatic infection | 85 (59 to 94) | 151 | ||
| US, ≥14 days post-dose 2, during delta-dominant period | PCR-confirmed COVID-19 associated hospitalization | 80 (73 to 85) | 154 | ||
| PCR-confirmed COVID-19-associated emergency department/urgent care encounters | 77 (74 to 80) | ||||
| US, ≥7 days post-dose 2 | PCR-confirmed infection caused by delta | 75 (71 to 78) | 156 | ||
| US, ≥7 days post-dose 2 | Hospitalization due to delta | 93 (84 to 96) | |||
| England, 2–≥25 wks post-dose 2 and 1–≥2 wks post-BNT162b2 booster | PCR-confirmed symptomatic disease caused by delta | wks post-dose 2: 2–9: 88.2 (86.7 to 89.5) 10–14: 77.7 (76.3 to 79.0) 15–19: 72.2 (71.0 to 73.4) 20–24: 64.8 (62.6 to 66.9) ≥25: 63.5 (61.4 to 65.5) Wks post-booster: 1–2: 92.2 (90.7 to 93.4) ≥2: 92.6 (92.0 to 93.1) |
159 | ||
| Denmark, 1–150 days post-dose 2 and 1–30 days post-booster | PCR-confirmed infection caused by deltae | Days post-dose 2 1–30: 86.7 (84.6 to 88.6) 31–60: 80.9 (79.0 to 82.6) 61–90: 72.8 (71.7 to 73.8) 91–150: 53.8 (52.9 to 54.6) Post-booster: 81.2 (79.2 to 82.9) |
161 | ||
| England, ≥14 days post-dose 2 and ≥14 days post-mRNA vaccine booster | PCR-confirmed symptomatic infection caused by delta | Cohort analysis: Post-dose 2: 55.9 (55.5 to 56.3) Post-booster: 88.6 (88.1 to 89.1) Test-negative case–control: Post-dose 2: 69.8 (69.4 to 70.2) Post-booster: 94.3 (93.9 to 94.6) |
162 | ||
| BNT162b2 or mRNA-1273 | US, ≥14 days post-dose 2, during delta-dominant period | PCR-confirmed infection | 74 (65 to 82) | 153 | |
| mRNA-1273 | US, ≥14 days post-dose 2 and post-booster | PCR-confirmed infection caused by deltad | Days post-dose 2: 14–90: 82.8 (69.6 to 90.3) 91–180: 63.6 (51.8 to 72.5) 181–270: 61.4 (56.8 to 65.5) ≥270: 52.9 (43.7 to 60.5) Post-booster: 95.2 (93.4 to 96.4) |
160 | |
| Hospitalization caused by deltad | Post-dose 2: 98.0 (87.2 to 99.7) | ||||
| Denmark, 1–150 days post-dose 2 and 1–30 days post-booster | PCR-confirmed infection caused by deltae | Days post-dose 2: 1–30: 88.2 (83.1 to 91.8) 31–60: 81.5 (77.7 to 84.6) 61–90: 72.2 (70.4 to 74.0) 91–150: 65.0 (63.6 to 66.3) Post-booster: 82.8 (58.8 to 92.9) |
161 | ||
| ChAdOx1 nCoV-19 | England, ≥14 days post-dose 2 | PCR-confirmed symptomatic COVID-19 caused by deltab | 67.0 (61.3 to 71.8) | 149 | |
| Scotland, ≥14 days post-dose 2 | PCR-confirmed infection caused by deltab | 60 (53 to 66) | 148 | ||
| UK, ≥14 days post-dose 2, during delta-dominant period | PCR-confirmed infection | 67 (62 to 71) | 152 | ||
| England, 2–≥25 wks post-dose 2 and 1–≥2 wks post-ChAdOx1 nCoV-19 booster | PCR-confirmed symptomatic disease caused by delta | wks post-dose 2: 2–9: 76.2 (63.7 to 84.4) 10–14: 64.9 (55.2 to 72.4) 15–19: 48.5 (44.7 to 52.0) 20–24: 45.4 (43.0 to 47.6) ≥25: 41.8 (39.4 to 44.1) Wks post-booster: 1–2: 87.0 (85.5 to 88.4) ≥2: 93.8 (93.2 to 94.3) |
159 | ||
| England, ≥14 days post-dose 2 and ≥14 days post-ChAdOx1 nCoV-19 booster | PCR-confirmed symptomatic infection caused by delta | Cohort analysis: Post-dose 2: 25.0 (24.3 to 25.7) Post-booster: 89.7 (88.9 to 90.4) Test-negative case–control: Post-dose 2: 43.7 (43.0 to 44.4) Post-booster: 93.8 (93.3 to 94.3) |
162 | ||
| BNT162b2 and/or mRNA-1273 and/or ChAdOx1 nCoV-19c | Norway, ≥7 days post-dose 2 | PCR- or whole-genome sequencing-confirmed infection by alpha or delta | 64.4 (60.6 to 68.2) | 187 | |
| Ad26.COV2.S | US, ≥14 days post-dose 1, during delta-dominant period | PCR-confirmed infection | 51 (−2 to 76) | 153 | |
| US, ≥14 days post-dose 1, during delta-dominant period | PCR-confirmed COVID-19-associated hospitalization | 60 (31 to 77) | 154 | ||
| PCR-confirmed COVID-19-associated emergency department/urgent care encounters | 65 (56 to 72) | ||||
| US, ≥14 days post-dose 2, during delta-dominant period | PCR-confirmed COVID-19-associated hospitalization | 95 (92 to 97) | |||
| PCR-confirmed COVID-19-associated emergency department/urgent care encounters | 92 (89 to 93) | ||||
| England, 2–≥25 wks post-dose 2 and ≥2 wks post-BNT162b2 booster | PCR-confirmed symptomatic disease caused by omicron | wks post-dose 2: 2–9: 88.0 (65.9 to 95.8) 10–14: 48.5 (24.3 to 65.0) 15–19: 34.1 (9.7 to 52.0) 20–24: 36.6 (0.4 to 59.6) ≥25: 34.2 (−5.0 to 58.7) Wks post-booster: ≥2: 75.5 (56.1 to 86.3) |
159 | ||
| Omicron | BNT162b2 | Denmark, 1–150 days post-dose 2 and 1–30 days post-booster | PCR-confirmed infection caused by omicrone | Days post-dose 2: 1–30: 55.2 (23.5 to 73.7) 31–60: 16.1 (−20.8 to 41.7) 61–90: 9.8 (−10.0 to 26.1) 91–150: −76.5 (−95.3 to −59.5) Post-booster: 54.6 (30.4 to 70.4) |
161 |
| England, adults aged ≥65 yrs, post-booster | PCR-confirmed symptomatic disease caused by omicron | wks post-BNT162b2 booster: 2–4: 65 5–9: 49 ≥10: 31 Wks post-mRNA-1273 booster: 2–4: 70 5–9: 57 |
163 | ||
| mRNA-1273 | US, ≥14 days post-dose 2 and post-booster | PCR-confirmed infection caused by omicrond | Days post-dose 2: 14–90: 30.4 (5.0 to 49.0) 91–180: 15.2 (0 to 30.7) 181–270: 0 (0 to 1.2) ≥270: 0 (0 to 1.7) Post-booster: 62.5 (56.2 to 67.9) |
160 | |
| Denmark, 1–150 days post-dose 2 | PCR-confirmed infection caused by omicrone | Days post-dose 2: 1–30: 36.7 (−69.9 to 76.4) 31–60: 30.0 (−41.3 to 65.4) 61–90: 4.2 (−30.8 to 29.8) 91–150: −39.3 (−61.6 to −20.0) |
161 | ||
| ChAdOx1 nCoV-19 | England, 2–≥25 wks post-dose 2 and 1–≥2 wks post-BNT162b2 booster | PCR-confirmed symptomatic disease caused by omicron | wks post-dose 2: 15–19: −54.7 (−174.0 to 12.6) 20–24: −13.2 (−60.2 to 20.1) ≥25: 5.9 (−29.7 to 31.7) Wks post-booster: 1–2: 71.9 (9.1 to 91.3) ≥2: 71.4 (41.8 to 86.0) |
159 | |
| England, adults aged ≥65 yrs, post- BNT162b2 or mRNA-1273 booster | PCR-confirmed symptomatic disease caused by omicron | wks post-booster: 2–4: 62–65 5–9: 48–56 ≥10: 32 (BNT162b2 booster only) |
163 | ||
a
CI, confidence interval; COVID-19, coronavirus disease 2019; HCP, health care professionals; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
b
Based on presence or absence of deletion in S gene at 69–70.
c
ChAdOx1 nCoV-19 was discontinued in Norway on 11 March, 2021, and those who received their first dose were offered a second dose of either BNT162b2 or mRNA-1273. In Norway, a mixed regimen of the two mRNA doses has been administered. The majority of patients in this study (81.3%) received BNT162b2 (187).
d
Specimens with S gene target failure were considered to be omicron, and specimens for which S gene was detected were assumed to be delta.
e
All specimens investigated for omicron by sequencing or variant-specific PCR; cases not identified as omicron assumed to be delta.