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National sero-prevalence of herpes simplex virus type 2 and co-infection with HIV-1: results of the 2007 Kenya AIDS Indicator Survey
N. Mugo1,2, S. Dadabhai3, K. Sabin4,5, I. Baya6, J. Muttunga7, W. Omwomo8, R. Bunnell9, I. Mohammed10, R. Kaiser9
1Kenyatta Hospital, Nairobi, Kenya, 2University of Nairobi, Nairobi, Kenya, 3University of California San Francisco, Nairobi, Kenya, 4Centers for Disease Control and Prevention, Atlanta, United States, 5World Health Organization, Geneva, Switzerland, 6National Public Health Laboratory Services, Nairobi, Kenya, 7Kenya Medical Research Institute, Nairobi, Kenya, 8US Agency for International Development, Nairobi, Kenya, 9Centers for Disease Control and Prevention, Nairobi, Kenya, 10National AIDS/STI Control Programme, Nairobi, Kenya
Background: Herpes Simplex Virus type 2 (HSV-2) is a sexually transmitted infection (STI) and the most common cause of genital ulcer disease. The role of HSV-2 in transmitting and acquiring HIV-1 has been established in multiple studies; thus, the epidemiology of HSV-2 is important for understanding HIV epidemics. The Kenya AIDS Indicator Survey (KAIS) provides Kenya's first national HSV-2 prevalence data.
Methods: KAIS was a population-based serosurvey conducted from August-December 2007 among men and women age 15-64. We conducted interviews and venous blood draws, but not physical examinations. HIV-1 status was determined through serial testing; HSV-2 status was determined by two reactive EIA tests. All sero-positive and 5% of sero-negative specimens were re-tested for quality assurance. Reported proportions are weighted for the sampling design.
Results: Of 19,840 eligible individuals, 91% completed an interview and 80% consented to blood draw. Among the 15,707 participants tested for HSV-2 and HIV-1, 35% were infected with HSV-2 (42% of women; 26% of men). Controlling for sex and age, persons ever married had significantly higher HSV-2 prevalence than those never married. HSV-2 prevalence among uncircumcised men was 1.5 times higher than circumcised men (39% vs. 24%). 81% of HIV-infected persons were co-infected with HSV-2. Prevalence of HIV-1 was 8 times higher among persons infected with HSV-2 compared to those not infected (16% vs. 2%). 27% of HIV-concordant negative couples, 50% of HIV-discordant couples, and 81% of HIV-concordant positive couples were concordant positive for HSV-2. 90% of those with HSV-2 reported no STI in the prior year.
Conclusions: Over 6 million adults were HSV-2-infected at the time of KAIS. Prevalence varied by sex, marital status and male circumcision. HSV-2 infected individuals were 8 times more likely to be infected with HIV-1. Those HSV-2-infected but HIV-uninfected are at increased risk for HIV-1 acquisition, especially in HIV-discordant relationships.
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