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.