Table 2.
Vaccine Effectiveness Against Alpha (B.1.1.7) Variant.
| Reference | Study Type | Population and Period | Location | Peer-Reviewed | Vaccine + | Reported Vaccine Efficacy |
|---|---|---|---|---|---|---|
| [16] | Phase 3, randomized, observer-blinded, placebo-controlled trial | 15,187 participants aged 18–84. 28 September–28 November 2020 |
UK | √ | NVX-CoV2373 | 86.3% (95% CI 71.3–93.5) against B.1.1.7 and 96.4% (73.8–99.5) against non-B.1.1.7 variants |
| [17] | Single-blind, randomized Phase 2 trial | 8534 participants aged ≥18. 31 May–13 November 2020 |
UK | √ | ChAdOx1 nCoV-19 | 70.4% (95% CI 43.6–84.5) against B.1.1.7 and 81.5% (67.9–89.4) against non-B.1.1.7 variants |
| [18] | Phase 2 and Phase 3 trials | N/A | UK | Χ | NVX-CoV2373 | 85.6% (CI Not reported) * |
| [19] | Test negative case-control study | Qatari resident. February-March, 2021 | Qatar | √ | BNT162b2 | Single dose: 29.5% (95% CI 22.9–35.5) Double dose: 89.5% (85.9–92.3) ≥14 days after the second dose |
| [20] | Test negative case-control study | 50,068 PCR-confirmed and negative for B.1.1.7 Qatari residents. 28 December 2020–10 May 2021 | Qatar | √ | mRNA-1273 | Single dose: 88.1% (95% CI 83.7–91.5) ≥14 days after first dose Double dose: 100% (91.8–100.0) ≥14 days after the second dose |
| [21] | Test negative case-control study | 19,109 participants aged ≥16. 26 October 2020–30 May 2021 | UK | √ | BNT162b2, ChAdOx1 nCoV-19 |
BNT162b2 and ChAdOx1 nCoV-19 Single dose: 48.7% (95% CI, 45.5–51.7). BNT162b2 Double dose: 93.7% (91.6–95.3) ChAdOx1 nCoV-19 Double dose: 74.5% (68.4–79.4) |
| [22] | Test negative case-control study | 25,589 participants aged ≥18. January–July 2021 | US | Χ | BNT162b2, mRNA-1273 | Results aggregated against all variants *: mRNA-1273: 86% (95% CI 81–90.6) *; BNT162b2: 76% (69–81) ≥14 days after the second dose. Effectiveness against B.1.1.7 was estimated to be higher than B.1.617.2 |
| [23] | Observational study | 126,367 fully vaccinated individuals. February–April 2021 | US | Χ | BNT162b2, mRNA-1273 | High efficacy in fully vaccinated individuals. Did not quantify. |
| [24] | Observational case-control study | 1210 hospitalized adults aged ≥18. 11 March–5 May 2021 | US | Χ | BNT162b2 and mRNA-1273 | BNT162b2: 84.3% (95% CI 74.6–90.3) * mRNA-1273 90.0% (82.0–94.4). Both Double doses |
| [25] | Test negative case-control study | 156,930 adults aged ≥70. 8 December 2020–19 February 2021 | UK | √ | BNT162b2, ChAdOx1 nCoV-19 |
BNT162b2 Single dose: 61% (95% CI 51–69) * from 28 to 34 days after vaccination and then plateaued, Double dose: 89% (85–93) after 14 days from the second dose. ChAdOx1 nCoV-19 Single dose: 60% (41–73) from 28 to 34 days, increasing to 73% (27–90) from day 35 |
| [26] | Observational study | Residents of Israel aged ≥16. 24 January–3 April 2021 |
Israel | √ | BNT162b2 | 95.3% (95% CI 94·9–95·7) * from 7 days or longer after the second dose |
| [27] | Prospective cohort study | 23,324 hospital staff aged ≥18. 7 December 2020–5 February 2021 | UK | √ | BNT162b2 | Single dose: 70% (95% CI 55–85) * 21 days after the first dose Double dose: 85% (74–96) 7 days after two doses |
| [28] | Retrospective cohort study | 245,226 Pescara resident aged ≥18. 2 January 2021–21 May 2021 |
Italy | √ | BNT162b2, ChAdOx1 nCoV-19, mRNA-1273 |
BNT162b2 Single dose: 55% (95% CI 0.34–0.60) *, Double dose: 98% (0.01–0.04) ChAdOx1 nCoV-19 Single dose: 95% (0.03–0.08) mRNA-1273 S Single dose: 93% (0.02–0.26) |
| [29] | Prospective cohort study | 10,412 care home residents aged ≥65. 8 December 2020–15 March 2021 |
UK | √ | BNT162b2, ChAdOx1 nCoV-19 | 56% (95% CI 19–76) at 28 to 34 days and 62% (23–81) * at 35 to 48 days after a single dose of ChAdOx1 or BNT162b2 |
| [30] | Prospective cohort study | 23,324 staff working in hospitals. 8 December 2020–5 February 2021 |
UK | Χ | BNT162b2 | Single dose: 72% (95% CI 58–86) * 21 days after the first dose Double dose: 86% (76–97) 7 days after two doses |
| [31] | Test negative case-control study | 4964 patients aged ≥65. 10 December 2020–31 May 2021 |
Europe | √ | BNT162b2, ChAdOx1 nCoV-19 |
BNT162b2 Single dose: 61% (95% CI 39–75) *, Double dose: 87% (74–93) ChAdOx1 nCoV-19 Single dose: 68% (39–83) |
| [32] | Case-control study (Questionnaire-based) | 41,151 questionnaire respondants and 3644 controls. 14 February–3 May 2021 | France | √ | BNT162b2, mRNA-1273 | Double dose: 86% (95% CI 81–90) 7 days after second dose. Reported efficacy for both mRNA vaccines aggregated |
| [33] | Test negative case-control study | 324,033 residents aged ≥16. 14 December 2020–19 April 2021 | Canada | √ | BNT162b2, mRNA-1273 | Single dose: 61% (95% CI 56–66) ≥14 days after the first dose Double dose: 90% (85–94) ≥7 days after the second dose (for both vaccines aggregated) Double dose against all variants combined: BNT162b2: 91% (88–93), mRNA-1273: 94% (86–97) |
| [34] | Observational study | 25,558 health care workers aged 20–69. 15 March 2020–13 May 2021 | Canada | Χ | BNT162b2, mRNA-1273 | Results aggregated against all variants *: Compared with community infection rates (for both vaccines aggregated): Single dose: 54.7% (95% CI 44.8–62.9); Double dose: 84.8% (75.2–90.7) |
| [35] | Test negative case-control study | 16,993 participants aged ≥70. 4 April–1 May 2021 |
Canada | √ | BNT162b2, mRNA-1273 | Single dose: 67% (95% CI 57–75) (for both vaccines aggregated, 85% of the study population were given BNT162b2) |
| [36] | Test negative case-control study | 682,071 symptomatic individuals aged ≥16. December 2020–March 2021 | Canada | Χ | BNT162b2, ChAdOx1 nCoV-19, mRNA-1273 |
Single dose: mRNA-1273 83% (95% CI 80–86); BNT162b2 66% (64–68); ChAdOx1 64% (60–68) ≥14 days after the first dose Double dose: mRNA-1273: 92% (86–96); BNT162b2: 89% (86–91) ≥7 days after the second dose. Insufficient data for ChAdOx1 |
+ NVX-CoV2373 (Novavax), ChAdOx1 nCoV-19 (AZD1222/Oxford–AstraZeneca), BNT162b2 (Pfizer–BioNTech), mRNA-1273 (Moderna) * Estimated efficacy due to the variant being dominant at the time of study. √ indicates the study has been peer reviewed and Χ indicates the study has not been peer reviewed.