Table 1. Demographics and clinical features of the study cohort.

*Within the ARI cohort, the specific viral etiology was known in 29 patients. The percentage reported is out of a total of 29 patients. Of these 29 patients, 4 patients tested positive for two different viruses concurrently on multiplex PCR–influenza and adenovirus (n = 1), influenza and human coronavirus OC43 (n = 1), parainfluenza and respiratory syncytial virus (n = 1), and parainfluenza and enterovirus virus (n = 1). **Any one of fatigue, somnolence, headache, concentration impairment or memory impairment.

	Dengue Cohort (n = 48)	ARI Cohort (n = 161)	p-value
Demographics
Age
Median (range), years	37.0 (21–68)	34.0 (22–79)	0.39
Male sex, no. (%)	30 (62.5)	46 (28.6)	<0.001
Ethnicity, no. (%)			0.21
Chinese	29 (60.4)	77 (47.8)
Malay	12 (25.0)	36 (22.4)
Indian	3 (6.3)	21 (13.0)
Others	4 (33.3)	27 (16.8)
Co-morbidities, no. (%)
Diabetes mellitus	2 (4.2)	5 (3.1)	0.72
Hypertension	4 (8.3)	16 (9.9)	0.74
Ischemic heart disease	2 (4.2)	2 (1.2)	0.19
Disposition
Hospitalised, no (%)	37 (77.1)	29 (18.0)	<0.001
Study Compliance
Completed at least 3 months of study follow-up, no (%)	39 (81.3)	158 (98.1)	<0.001
Viral Etiology
Severe dengue, no. (%)	1 (2.0)	-	NA
Respiratory virus type, no. (%)*
Influenza A & B	-	14 (48.3)
Rhinovirus	-	6 (20.7)
Adenovirus	-	4 (13.8)
Human coronavirus (OC43)	-	4 (13.8)
Parainfluenza	-	3 (10.3)
Human coronavirus (NL63)	-	1 (3.4)
Enterovirus	-	1 (3.4)
Clinical Features
Symptom type at presentation, no (%)
Any symptom**	46 (95.8)	152 (94.4)	1.00
Fatigue	38 (79.2)	136 (84.5)	0.51
Somnolence	32 (66.7)	93 (57.8)	0.32
Headache	29 (60.4)	119 (74.0)	0.07
Concentration impairment	29 (60.4)	95 (59.0)	0.86
Memory impairment	13 (27.1)	28 (17.4)	0.15