Table 1.
Number and rate per 100 person-years at risk of SARS-CoV-2 re-infections among Ku-gaa-gii pimitizi-win participants having evidence of incident infection (n = 381), by method of identification and observation period
| Test-only method | Longitudinal serology | Comprehensive method | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Period of Interest | N | Rate/100 YAR (95% CI*) | N Proa | N Pob | N Indc |
N
total |
Rate/100 YAR (95% CI*) | N | Rate/100 YAR (95% CI*) |
| March 2020 to final interview (n = 381) | 37 | 8.71 (6.2–11.9) | NA | NA | NA | NA | NA | 135 | 31.78 (26.8–37.5) |
| Baseline interview to final interview (n = 381) | 31 | 8.98 (6.2–12.6) | 21 | 40 | 37 | 98 | 28.37 (23.2–34.4) | 129 | 37.35 (31.3–44.2) |
| Specific periods: | |||||||||
| March 2020 to baseline Interview (n = 202) | 6 | 5.74 (2.3–11.9) | NA | NA | NA | NA | NA | 6 | 5.74 (2.3–11.9) |
| Baseline interview to 3-mth interview (n = 221) | 0 | 0 (0–0) | 0 | 3 | 1 | 4 | 9.33 (3.0-22.5) | 4 | 9.33 (3.0-22.5) |
| Most recent interview (baseline or 3mth) to 6-month interview (n = 318) | 12 | 21.47 (11.6–36.5) | 8 | 19 | 6 | 33 | 59.05 (41.3–82.0) | 45 | 80.52 (59.4-106.8) |
| Most recent interview (baseline, 3- or 6-mth) to 9-month interview (n = 381) | 12 | 17.86 (9.7–30.4) | 7 | 13 | 17 | 37 | 55.06 (39.3–75.1) | 49 | 72.92 (54.5–95.6) |
| Most recent interview (baseline, 3-, 6-, or 9-mth) to 12-month interview (n = 381) | 7 | 9.34 (4.1–18.5) | 6 | 5 | 13 | 24 | 32.02 (21.0-46.9) | 31 | 41.36 (28.6–58.0) |
CI = Confidence Interval; YAR = Years at risk
*95% confidence interval calculated using Poisson regression
aPro=Probable re-infection = Serology-identified re-infections with supporting anti-R or anti-S evidence unexplained by recent vaccination
bPo=Possible re-infection = Serology-identified re-infections with stable or supporting anti-R or anti-S evidence with recent vaccination
cInd=Indeterminate re-infection = Serology-identified re-infections without supporting anti-R or anti-S evidence