Table 1. Efficacy and effectiveness of COVID-19 vaccines against SARS-CoV-2 infection (symptomatic and asymptomatic), 1 January–14 May 2021 (n = 26).
| Study | Country | Study design | Study population (n) | Age | Circulating variant | Vaccine | Time point of analysis after vaccine dose | Adjusted vaccine efficacy/effectiveness (95% CI) |
|
|---|---|---|---|---|---|---|---|---|---|
| After dose 1 | After dose 2 | ||||||||
| Abu-Raddad [23]; 10 May 2021 | Qatar | Case–control study (test-negative design) | General population (cases: n = 35,979; controls: n = 35,979) | Adults (median: 32 years) | Alpha (B.1.1.7); Beta (B.1.351) | Comirnaty | After dose 1; ≥ 14 days after dose 2 |
Alpha: 29.5% (22.9–35.5) Beta: 16.9% (10.4–23.0) |
Alpha: 89.5% (85.9–92.3) Beta: 75.0% (70.5–78.9) |
| Amit [3]; 18 Feb 2021 | Israel | Retrospective cohort study | HCW (n = 9,109) | Adults | Not reported | Comirnaty | 15–21 days after dose 1; 22–28 days after dose 1; 6 days after dose 2 |
65% (43–68) 75% (72–84) (including some persons vaccinated with two doses) |
Not reported |
| Andrejko [4]; 10 Apr 2021a | US | Case–control study (test-negative design) | Population-based (325 cases; 320 controls) |
≥ 18 years | Not reported | Comirnaty, Moderna | 8–14 days after dose 1 or dose 2; ≥ 15 days after dose 1 or 2 |
66.3% (− 68.7–93.3) 58.9% (− 9.7–84.5%) |
78.4% (23.2–94.3) 85.7% (67.2–93.9) |
| Björk [24]; 21 Apr 2021 |
Sweden | Cohort study | Population-based (n = 805,741) | 18–64 years | Not reported | Comirnaty | > 14 days after dose 1; > 7 days after dose 2 |
42% (14–63) | 86% (72–94) |
| Britton [5]; 19 Mar 2021a | US | Retrospective cohort study | LTCF inhabitants (n = 463) | Not reported | Not reported | Comirnaty | > 14 days after dose 1 | 63% (33–79) | Not reported |
| Chodick [6]; 29 Jan 2021a | Israel | Retrospective cohort study | Insurance members (n = 503,875) |
≥ 16 years, mean: 59.7 years (SD: 14.7) | Not reported | Comirnaty | > 13 days after dose 1 | 51.4% (− 7.2–78) | Not reported |
| Corchado-Garcia [25]; 30 Apr 2021 |
US | Retrospective cohort study | Mayo Clinics health system records (vaccinated: 2,195; unvaccinated: 21,950) | ≥ 18 years | Not reported | COVID-19 vaccine Janssen | > 15 days after dose | 76.7% (30.3–95.3) | Not applicable |
| Dagan [7]; 15 Apr 2021 | Israel | Matched case–control study | Insurance members (n = 1,193,236) |
≥ 16 years, median: 45 years | 80% Alpha (B.1.1.7) | Comirnaty | ≥ 7 days after dose 2 | 46% (40–51) | 92% (88–95) |
| EMA Assessment report COVID-19 Vaccine Janssen [22]; 11 Mar 2021 |
Multi-centre (incl. US, Brazil, South Africa) | RCT (phase 3-licensure trial) | Vaccine group (n = 19,306); placebo group (n = 19,178) | ≥ 18 years | Beta (B.1.351); Zeta (P.2); D614G-carrying ‘WT/ref’ | COVID-19 vaccine Janssen | 14 days after vaccination | 67.2% (56.86–75.26) | Not applicable |
| Emary [8]; 30 Mar 2021 | UK | RCT | Randomised population, 66% working in health and social care settings (vaccinated n = 4,244; control: n = 4,290) |
≥ 18 years | Alpha (B.1.1.7); Non-Alpha | Vaxzevria | ≥ 15 days after dose 2 | Not reported | Non-Alpha: 77.3% (65.4–85.0); Alpha: 61.7% (36.7–76.9) |
| Fabiani [26]; 29 Apr 2021 |
Italy | Retrospective cohort study | HCW (n = 6,423) | Mean: 47.1 years (SD: 10.8 years) | Not reported | Comirnaty | 14–21 days after dose 1; ≥ 7 days after dose 2 |
84% (40–96) | 95% (62–99) |
| Glampson [9]; 10 Apr 2021a | UK | Retrospective cohort study | Population-based (n = 2,183,939; (n = 389,587 vaccinated) | ≥ 16 years | Alpha (B.1.1.7) | Comirnaty; Vaxzevria | 28 days after dose 1 | Vaxzevria: 74% (HR: 0.26 (0.19–0.35) Comirnaty: 78% (HR: 0.22 (0.18–0.27)) |
Not reported |
| Guijarro [10]; 26 Mar 2021a |
Spain | Cohort study | HCW: n = 2,590 (cf.d with average population: n = 170,513) | Not reported | Not reported | Comirnaty | 2–4 weeks after dose 1; 7 days after dose 2 |
63% incidence reduction (cf.d with average population) | 99% incidence reduction (cf.d with average population) |
| Haas [11]; 24 Mar 2021 | Israel | Cohort study | Surveillance data (national); n = 202,684 SARS-CoV-2 infections; n = 102,012 non-vaccinated | ≥ 15 years | 94.5% Alpha (B.1.1.7) | Comirnaty | ≥ 7 days after dose 2; ≥ 14 days after dose 2 |
Not reported | 95.3% (94.9–95.7) 96.5% (96.3–96.8) |
| Hall [12]; 22 Feb 2021 | UK | Cohort study | HCW without previous SARS-CoV-2 infection (n = 23,324) | Median: 46.1 years (IQR: 36.0–54.1) | Alpha (B.1.1.7) | Comirnaty | 21 days after dose 1; 7 days after dose 2 |
72% (58–86) | 86% (76–97) |
| Lumley [13]; 12 Mar 2021 | UK | Cohort study | HCW (n = 13,109) | Median: 39 years (range: 30–50) | Alpha (B.1.1.7 ) | Comirnaty; Vaxzevria | > 14 days after dose 1 and dose 2 | 64% (aIRR = 0.36 (0.26–0.50)) |
90% (aIRR = 0.10 (0.02–0.38)) |
| Mason [27]; 22 Apr 2021a |
UK | Matched case–control study | Population (n = 170,226) | 80–83 years | Alpha (B.1.1.7) | Comirnaty | 21 to 27 days after dose 1; 35–41 days after dose 1 and 7 days after dose 2 |
55.2% (40.8 - 66.8) 70.1% (55.1–80.1) (including persons vaccinated with two doses |
Not reported |
| Menni [28]; 27 Apr 2021 |
UK | Cohort study | Users of the COVID Symptom study app (vaccinated: n = 103,622; unvaccinated: n = 464,356) | 16–99 years; Comirnaty: 54.5 years (SD: 14.3); Vaxzevria: 60.8 years (SD: 13.5); unvaccinated: 49.4 years (SD: 14.6) | Not reported | Comirnaty; Vaxzevria | Comirnaty: 45–59 days after dose 1; Vaxzevria: 21–44 days after dose 1 |
Comirnaty: 72% (63–79); Vaxzevria: 60% (49–68) |
Not reported |
| Monge [14]; 15 Apr 2021a | Spain | Retrospective cohort study | LTCF inhabitants (n = 299,209) |
Mean: 85.9 years | Not reported | 99.8% Comirnaty | 15–21 days after dose 1; ≥ 7 days after dose 2 |
51.0% (49.7–52.3) | 81.2% (80.2–82) |
| Moustsen-Helms [15]; 9 Mar 2021a | Denmark | Retrospective cohort study | LTCF inhabitants (n = 39,040); HCW (n = 331,039) |
LTCF median: 84 years (IQR: 77–90); HCW median: 47 years (IQR: 36–57) |
Not reported | LTCF: > 99% Comirnaty HCW: 89% Comirnaty |
> 14 days after dose 1; > 7 days after dose 2 |
HCW: 17% (4–28), LTCF inhabitants: 21% (− 11–44) |
HCW: 90% (82–95) LTCF inhabitants: 64% (14–84) |
| Pawlowski [16]; 27 Feb 2021a | US | Matched case–control study | 62,138 persons tested at Mayo Clinics | ≥ 18 years | Not reported | Comirnaty; Moderna | > 36 days after dose 1; 1–2 weeks after dose 2 | 83.4% (60.2–94.3) | 88.7% (68.4–97.1%) |
| Pritchard [29]; 23 Apr 2021a |
UK | Prospective cohort study | Population-based (n = 373,402) | ≥ 16 years | Alpha (B.1.1.7); Non-Alpha | Comirnaty; Vaxzevria | ≥ 21 days after dose 1 and dose 2 (only Comirnaty) | Alpha: 66% (OR: 0.34 (0.28–0.41)) Non-Alpha: 71% (OR: 0.29 (0.16–0.51)) |
Alpha: 78% (OR: 0.22; (0.15–0.32)) Non-Alpha: 82% (OR: 0.18 (0.06–0.51)) |
| Shrotri [17]; 7 Apr 2021a | UK | Cohort study | LTCF inhabitants (n = 10,412) |
Mean: 86 years | Mainly Alpha (B.1.1.7) | Comirnaty (33%); Vaxzevria (67%) | 35–48 days after dose 1 | 62% (23–81) (HR: 0.38 (0.19–0.77)) Comirnaty: 65% (HR: 0.35 (0.17–0.71) Vaxzevria: 68% (HR 0.32 (0.15–0.66)) |
Not reported |
| Swift [30]; 26 Apr 2021a |
US | Retrospective cohort study | HCW at Mayo Clinics (n = 71,152) | Median: 41 years | Not reported | Comirnaty; Moderna | > 14 days after dose 1 and ≤ 14 days from dose 2; > 14 days after dose 2 |
Comirnaty: 78.1% (71.1–82.0) Moderna: 91.2% (80.6- 96.1) |
Comirnaty: 96.8% (95.3–97.8) Moderna: 98.6% (90.1–99.8) |
| Tang [31]; 6 May 2021 |
US | Cohort study | HCW (n = 5,217) | Adults | Not reported | Comirnaty | ≥ 12 days after dose 1 and before dose 2; ≥ 7 days after dose 2 |
58% (IRR: 0.42 (0.26–0.70)) | 96% (IRR: 0.04 (0.02–0.09)) |
| Thompson [18]; 2 Apr 2021 |
US | Prospective cohort study | HCW, first responders, other essential and frontline workers (n = 3,950) | ≥ 18 years | Not reported | Comirnaty (62.7%); Moderna (29.6%); unknown mRNA vaccine (7.7%) | ≥ 14 days after dose 1 and dose 2 | 80% (59–90) | 90% (68–97) |
aIRR: adjusted incidence rate ratio; CI: confidence interval; COVID-19: coronavirus disease; HCW: healthcare workers; HR: hazard ratio; IQR: interquartile range; IRR: incidence rate ratio; LTCF: long-term care facility; RCT: randomised controlled trial; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; SD: standard deviation; UK: United Kingdom; US: United States.
a Preprint.