Table 1.
Studies Through August 18, 2021, That Show Prior COVID-19 Infection Reduces Risk for Reinfection.
| Setting | Percent Reduction in Reinfection | Sample Size | Follow-Up | Reference |
|---|---|---|---|---|
| Israel | 94.8% | 238,702 | 9.92 million person-months | Goldberg et al., April 20, 2021 |
| England | 84.0% | 25,661 | Median 9.2 months (IQR: 7.3-9.7) | Hall et al., April 9, 2021 |
| Denmark | 80.5% | 525,339 | Up to 10.3 months | Hansen et al., March 27, 2021 |
| USA | 100.0% | 5,052 | 12625.2 person-months | Kojima et al., July 8, 2021 |
| US Marines | 82.0% | 3,076 | 1.9 months | Letizia et al., April 15, 2021 |
| Austria | 91.0% | 8,900,480 | Up to 9.4 months | Pilz et al., February 13, 2021 |
| USA | 84.0% | 16,101 | 8.4 months | Rennert et al., May 16, 2021 |
| USA | 81.8% | 150,325 | Up to 9.8 months | Sheehan et al., March 15, 2021 |
| USA | 100.0% | 52,238 | Median 5.1 months (IQR: 2.7-6.4) | Shrestha et al., June 1, 2021 |
| Italy | 94.0% | 13,496 | Mean 9.3 months (SD 1.4) | Vitale et al., May 28, 2021 |
| Weighted average | 90.4% | 9,930,470 |