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.