Table 1.

Patient Characteristics

	Acute			Late
Characteristic	Developed Rebound Symptoms (n = 2)	No Rebound Symptom Development (n = 5)	Rebound After NMV-r (n = 6)	Rebound Without Treatment (n = 2)	No Rebound Symptoms (n = 1)
Gender
Male	1 (50%)	1 (20%)	3 (50%)	1 (50%)	0 (0%)
Female	1 (50%)	4 (80%)	3 (50%)	1 (50%)	1 (100%)
Age, years
Median [min, max]	39 [33, 45]	50 [49, 65]	42.5 [33, 74]	44.5 [35, 54]	23
Comorbidity
None	0 (0%)	1 (20%)	0 (0%)	2 (100%)	1 (100%)
Pulmonary	1 (50%)	1 (20%)	2 (33.3%)	0 (0%)	0 (0%)
Immunocompromised	1 (50%)a	1 (20%)b	2 (33.3%)c	0 (0%)	0 (0%)
Cardiac	0 (0%)	0 (0%)	2 (33.3%)	0 (0%)	0 (0%)
Other	0 (0%)	2 (40%)d	0 (0%)	0 (0%)	0 (0%)
Days from initial symptom onset to visit
Median [min, max]	3.5 [3, 4]e	3 [1, 3]	16 [11, 17]f	19 [14, 24]	8
Initial symptoms
Upper respiratory only	0 (0%)	2 (40%)	2 (33.3%)	1 (50%)	0 (0%)
Upper and lower respiratory	1 (50%)	1 (20%)	1 (16.7%)	0 (0%)	1 (100%)
Upper respiratory and constitutional	1 (50%)	1 (20%)	3 (50%)	1 (50%)	0 (0%)
Upper respiratory, lower respiratory, and constitutional	0 (0%)	1 (20%)	0 (0%)	0 (0%)	0 (0%)
Receipt of NMV-r
Recipients	2 (100%)	2 (40%)	6 (100%)	0 (0%)	0 (0%)
Nonrecipients	0 (0%)	2 (40%)	0 (0%)	2 (100%)	1 (100%)
Day of illness NMV-r started
Median [min, max]	2.5 [2, 3]	2.5 [2, 3]	2.5 [1, 4]	NA	NA
Day of illness symptoms returned
Median [min, max]	13 [11, 15]	NA	12.5 [11, 15]	14.5 [9, 20]	NA
Number of days symptoms returned after completing NMV-r
Median [min, max]	6 [4, 8]	NA	6.5 [3, 9]	NA	NA

Four rebound patients repeated rapid antigen tests after initial symptom resolution. Three became negative and the fourth became weakly positive. All 4 became positive again when rebound symptoms returned.

Abbreviations: NA, not applicable; NMV-r, nirmatrelvir-ritonavir.

^aAnkylosing spondylitis on golimumab.

^bIdiopathic thrombocytopenic purpura status post-splenectomy.

^cMultiple sclerosis on natalizumab; Ankylosing spondylitis on golimumab.

^dPrimary biliary cirrhosis and obesity; epithelioid hemangioendothelioma and hypothyroidism.

^ePatients 1 and 2 were seen for acute visits 3 and 4 days from initial symptom onset, respectively.

^fPatients 1 and 2 were again seen 16 days and 11 days from initial symptom onset, respectively.