Table 2.

Pair-level demographic and clinical characteristics for the Hamburg outbreak

Covariate	Level	n (%) of all pairs
		(n = 3633)
City	Same city	2148 (59.1%)
	Different city	1485 (40.9%)
Nationality	Both German	2129 (58.6%)
	Same foreign country	19 (0.5%)
	One German, one foreign country	1315 (36.2%)
	Different foreign countries	170 (4.7%)
Sex	Male to male	2401 (66.1%)
	Female to female	120 (3.3%)
	Male to female	757 (20.8%)
	Female to male	355 (9.8%)
Age group	Same age group	695 (19.1%)
	Different age group	2938 (80.9%)
Smear status	Infector smear–	2339 (64.4%)
	Infector smear+	1294 (35.6%)
HIVa status	Infector HIV–	3463 (95.3%)
	Infector HIV+	170 (4.7%)
Substance abuse	Both yes	1372 (37.8%)
	Both no	526 (14.5%)
	Different	1735 (47.8%)
Residence	Both permanent	2473 (68.1%)
	Both homeless	105 (2.9%)
	Different	1055 (29.0%)
Affiliation to alcohol-consuming milieu/street scene	Both affiliated	2062 (56.8%)
	Both not affiliated	210 (5.8%)
	Different	1361 (37.5%)
Observation time difference	<1 year	546 (15.0%)
	1–2 years	485 (13.3%)
	2–3 years	374 (10.3%)
	3–4 years	305 (8.4%)
	>4 years	1923 (52.9%)
SNPb distance	<2 SNPs	796 (21.9%)
	2–12 SNPs	2452 (67.5%)
	>12 SNPs	385 (10.6%)
Confirmed contact	Yes	51 (1.4%)
	No	408 (11.2%)
	Unknown	3174 (87.4%)

^aHuman immunodeficiency virus.

^bSingle nucleotide polymorphism.