Table 2.
Characteristics of patients.
| Reference Number and First Author | Number of Patients | Sex/Gender | Age (Mean/Median) | Comparison Group |
|---|---|---|---|---|
| 1 [21] Al-Aly et al. | 33,940 vaccinated | 91.0% Male; 9.0% Female | 67.0 years (median) | Matched unvaccinated patients |
| 2 [22] Antonelli et al. | 1,240,009 (cases 1: first dose), 971,504 (cases 2: second dose) | Cases 1: 62.5% Female, 37.5% Male; Cases 2: 61.2% Female, 38.8% Male | Cases 1: 50.2 years (mean); Cases 2: 52.9 years (mean) |
Controls matched by post-vaccination test, healthcare worker status, sex |
| 3 [23] Ayoubkhani et al. | 3333 double-vaccinated, 3090 matched unvaccinated | NR | Double-vaccinated: 49 years (mean); Unvaccinated: 47 years (mean) | Matched unvaccinated patients with COVID-19 |
| 4 [24] Azzolini et al. | 739 (29% of 2560 participants had COVID-19) | 32.7% Female, 26.1% Male (among COVID-19 cases) | 44.3 (mean) | Healthcare workers not requiring hospitalization for COVID-19 |
| 5 [25] Brannock et al. | Clinic-based: 47,404; Model-based: 198,514 | Clinic-based: 65.0% Female, 35.0% Male; Model-based: 64.6% Female, 35.4% Male | Clinic-based: 48.19 years (mean); Model-based: 47.23 years (mean) | Unvaccinated patients with COVID-19 |
| 6 [26] Ballouz et al. | 1350 vaccinated | 52.5% Female; 47.5% Male | 48 years (median) | Individuals infected with different SARS-CoV-2 variants (Wildtype, Delta, Omicron) |
| 7 [27] Emecen et al. | 5610 vaccinated | 51.8% Female, 48.2% Male | 43.1 years (mean) | NR |
| 8 [28] Ioannou et al. | 198,601 vaccinated | 89.1% Male, 10.9% Female | 60.4 years (mean) | Unvaccinated patients with COVID-19 |
| 9 [29] Meza-Torres et al. | 7,396,702 vaccinated | 55.89% Female, 44.11% Male | 44.5 years (median) | Unvaccinated patients with COVID-19 |
| 10 [30] Mohr et al. | 419 vaccinated | 84.0% Female, 15.3% Male | Age distribution: 21.5% (18–29 years), 39.9% (30–39 years), 20.3% (40–49 years), 18.4% (50–64 years) | Unvaccinated healthcare workers with COVID-19 |
| 11 [31] Taquet et al. | 10,024 vaccinated individuals matched to 9,479 controls | 59.4% Female, 50.6% Male | Vaccinated 57.0 years (mean), Unvaccinated 57.6 years (mean) | Unvaccinated (with influenza vaccine) patients with COVID-19 |
| 12 [32] van der Maaden et al. | 9166 cases, 1698 test-negative controls, 3708 population controls | NR | NR | Unvaccinated patients with COVID-19 |
| 13 [33] Zisis et al. | 1,578,719 COVID-19 patients (25,225 vaccinated) | 59.8 female, 50.2% male | Vaccine group: 54.82 years (mean); No-vaccine group: 42.91 years (mean) | Unvaccinated patients with COVID-19 |