Table 3.

STI incidence over 12 months, by site

	Overall (N=451)	Cape Town (N=141)	Johannesburg (N=162)	Harare (N=148)
Neisseria gonorrhoeae
Events	51	32	2	17
Person-years	445.58	134.13	161.23	150.23
Event rate (100 person-years)	11.4	23.9	1.2	11.3
95% exact CI for event rate	(8.5, 15.0)	(16.3, 33.7)	(0.2, 4.5)	(6.6, 18.1)
Chlamydia trachomatis
Events	123	50	38	35
Person-years	441.7	135.1	155.2	151.4
Event rate (100 person-years)	27.8	37	24.5	23.1
95% exact CI for event rate	(23.1, 33.2)	(27.5, 48.8)	(17.3, 33.6)	(16.1, 32.1)
Trichomonas vaginalis
Events	30	6	7	17
Person-years	448.8	138	161.2	149.6
Event rate (100 person-years)	6.7	4.3	4.3	11.4
95% exact CI for event rate	(4.5, 9.5)	(1.6, 9.5)	(1.7, 9.0)	(6.6, 18.2)

STI, sexually transmitted infection.