Table 1.
Characteristics of the clinical studies included in the network meta-analysis.
| Study and Year | Trial Number | Study Characteristics | Vaccine Developer | Dose and Route of Administration | Number of Scheduled Doses (Time of Inoculations) | Type of Candidate Vaccine | Study Duration | Characteristics of Vaccine Recipients | Participating Countries | Age (Mean/Median and Range/SD) | Male (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Baden et al., 2021 | NCT04470427 | Phase III, multicenter, randomized, observer-blind, placebo-controlled | Moderna/National Institute of Allergy and Infectious Diseases’ Vaccine Research Center | mRNA-1273 (100 μg IM) | Prime and boost inoculation (0, 28 days) | mRNA vaccine | 27 July 2020 to 21 November 2020 | Persons 18 years of age or older with no known history of SARS-CoV-2 infection and with locations or circumstances that put them at an appreciable risk of SARS-CoV-2 infection | USA | 51.4 (18–95) | 52.7 |
| Ramasamy et al., 2020 | NCT04400838 | Phase II/III, multicenter, randomized, single-blind, placebo-controlled | University of Oxford/AstraZeneca | ChAdOx1-S (3.5–6.5 × 1010 viral particles IM) | Prime and boost inoculation (0, 28 days) | Virus-vectored vaccine | May 30, 2020 to 26 October 2020 | Adults aged 18–55 years, then adults aged 56–69 years, and then adults aged 70 years and older, without severe or uncontrolled medical comorbidities | UK | 18–55 years: 43.2 (22–55); 56–69 years: 60.4 (56–69.4); ≥70 years: 73 (70–82) | 18–55 years: 36.4; 56–69 years: 55.0; ≥70 years: 64.3 |
| Voysey et al., 2021 | NCT04324606, NCT04400838, NCT04444674, ISRCTN89951424 | Phase II/III, multicenter, randomized, single-blind, placebo-controlled | University of Oxford/AstraZeneca | ChAdOx1-S (3.5–6.5 × 1010 viral particles IM) | Prime and boost inoculation (0, 28 days) | Virus-vectored vaccine | 23 April 2020 to 6 November 2020 | Health adults aged 18 or older | UK Brazil South Africa | ≥18 | 43.6 |
| Walsh et al., 2020 | NCT04368728 | Phase I, multicenter, randomized, observed-blind, placebo-controlled | BioNTech/Fosun Pharma/Pfizer | BNT162b2 (30 µg IM) | Prime and boost inoculation (0, 21 days) | mRNA vaccine | 4 May 2020 to 22 June 2020 | Healthy adults 18 to 55 years of age or 65 to 85 years of age | USA | 18–55 years: 36.1 (19–54); 65–85 years: 69.1 (65–77) | 18–55 years: 38.1; 65–85 years: 47.6 |
| Polack et al., 2020 | NCT04368728 | Phase III, multicenter, randomized, observed-blind, placebo-controlled | BioNTech/Fosun Pharma/Pfizer | BNT162b2 (30 µg IM) | Prime and boost inoculation (0, 21 days) | mRNA vaccine | 27 July 2020 to 14 November 2020 | Adults 16 years of age or older who were healthy or had stable chronic medical conditions | USA Argentina Brazil South Africa | 52 (16–91) | 50.6 |
| Logunov et al., 2021 | NCT04530396 | Phase III, multicenter, randomized, double-blind, placebo-controlled | Gamaleya Research Institute | Gam-COVID-Vac (1 ± 0.5 × 1011 viral particles IM) | Prime and boost inoculation (0, 21 days) | Virus-vectored vaccine | 7 September 2020 to 24 November 2020 | Adults aged 18 or older with no known history of SARS-CoV-2 infection, and without severe or uncontrolled medical comorbidities | Russia | 45.3 (12.0) | 61.2 |
| Palacios et al., 2021 | NCT04456595 | Phase III, multicenter, randomized, double-blind, placebo-controlled | Sinovac | CoronaVac (3 μg IM) | Prime and boost inoculation (0, 14 days) | Inactivated vaccine | 21 July 2020 to 16 December 2020 | Participants aged 18 or older without previous SARS-CoV-2 infection | Brazil | 39.5 (10.8) | 35.8 |
| Kaabi et al., 2021 | NCT04510207 | Phase III, multicenter, randomized, double-blind, placebo-controlled | The Beijing Institute of Biological Products Co, Ltd., | HB02 (4 μg IM) or WIV04 (5 μg IM) | Prime and boost inoculation (0, 21 days) | Inactivated vaccine | 16 July 2020 to 20 December 2020 | Participants aged 18 or older without previous SARS-CoV-2 infection | United Arab Emirates (Abu Dhabi Sharjahand Bahrain) | 36.1 (9.3) | 84.4 |