Volume 28, Number 12—December 2022
Research
Daily Rapid Antigen Exit Testing to Tailor University COVID-19 Isolation Policy
, Christine Chen, Chrispin Chaguza, Anne M. Hahn, Nathan D. Grubaugh1, Madeline S. Wilson1, and for the Yale COVID-19 Resulting and Isolation Team2
Table 2
Event time ratios of the association between covariates in study of students in a university-managed isolation program, January 1–February 11, 2022*
| Covariate | Sample size | ETR (95% CI) | p value |
|---|---|---|---|
| Time since last negative test, d | |||
| <4† | 155 | NA | NA |
| 5–9 | 40 | 0.88 (0.77NA1.01) | 0.065 |
| >10 |
68 |
0.85 (0.75NA0.96) |
0.008 |
| Symptoms at diagnosis | |||
| N | 104 | NA | Referent |
| Y |
159 |
1.13 (1.02NA1.25) |
0.016 |
| Ct value at diagnosis |
263 |
1 (0.99NA1) |
0.378 |
| Prior infection >90 d | |||
| N† | 244 | NA | NA |
| Y |
19 |
0.5 (0.33NA0.76) |
0.001 |
| No. dose/time since last dose | |||
| 2 doses / >5 mo† | 44 | NA | NA |
| 2 doses / <5 mo | 31 | 1.29 (0.97NA1.73) | 0.083 |
| 3 doses |
188 |
1.2 (1.04NA1.39) |
0.012 |
| Primary vaccine brand | |||
| Janssen/Johnson & Johnson† | 24 | NA | NA |
| mRNA | 239 | 1.21 (0.89NA1.65) | 0.219 |
*N = 263 persons who were fully vaccinated with Pfizer-BioNTech (https://www.pfizer.com), Moderna (https://modernatx.com), or Janssen/Johnson & Johnson (https://jnj.com), did not additionally receive an international vaccine, and did not have a missing Ct value or symptom status. ETR >1 is associated with prolonged RAT positivity duration compared to the reference group. An ETR <1 is associated with a decreased RAT positivity duration. Ct, cycle threshold; Dx, diagnosis; ETR, event time ratio; mRNA, either of the mRNA vaccines from Pfizer or Moderna; NA, not applicable; RAT, rapid antigen test.
1These authors contributed equally to this article.
2Members of the team are listed at the end of this article.