Table 1.

The number and percentages of subjects who were seroconverted by age group and minimum number of contacts.

	minimum number of contacts
age group	1–2 (n = 54)	3–4 (n = 94)	5–6 (n = 130)	7–8 (n = 94)	9–10 (n = 57)	11–19 (n = 160)	20–100 (n = 155)	100+ (n = 18)	% of positive
3–9 (n = 21)	0	2	4	0	1	1	3	0	52.4
10–19 (n = 89)	1	4	3	1	2	6	15	0	36.0
20–29 (n = 85)	0	0	1	0	2	1	4	0	9.4
30–39 (n = 60)	0	0	0	2	0	2	0	1	8.3
40–49 (n = 177)	1	0	1	3	1	5	2	1	7.9
50–59 (n = 202)	1	0	2	0	0	3	0	0	3.0
60–69 (n = 85)	0	0	1	0	0	0	0	0	1.2
70+ (n = 43)	0	0	0	0	0	0	0	0	0
% of positive	5.6	6.4	9.2	6.4	10.5	11.3	15.5	11.1