HIV prevalence in Kenyan adults has remained relatively steady since 2003, at around 7%, according to a major national study presented to the Sixteenth Conference on Retroviruses and Opportunistic Infections (CROI) on Wednesday. However, fewer than one in five HIV-positive adults were aware of their HIV status, and over half had never been tested for HIV at all.
The first population-based HIV serosurvey in Kenya, the 2003 Kenya Demographic and Health Survey (KDHS), found an overall prevalence rate of 6.7% among adults 15 to 49 years of age (4.6% in men and 8.7% in women). Access to antiretroviral therapy (ART) has grown 13-fold in Kenya since that survey, and a new surveillance survey – the Kenya AIDS Indicator Survey, or KAIS – was conducted between August and December 2007 by a collaborative group of Kenyan national governmental organisations and the University of California, San Francisco.
Ibrahim Mohammed, of the National AIDS/STI Control Program, Nairobi, Kenya, presented findings. KAIS was a more robust surveillance tool than KDHS, including adults 15 to 64 years of age, collecting data on Herpes simplex virus (HSV-2) infection, syphilis and male circumcision, and including questions on testing history, knowledge of HIV status (self and partner), CD4 cell counts, and use of ART and cotrimoxazole.
A two-stage cluster design was used to achieve a nationally representative sample. The study used both a household and an individual questionnaire, plus a blood draw for HIV antibody, HSV and syphilis testing, as well as CD4 cell counts in HIV-infected respondents. Test results were returned to health facilities for participants to receive results and appropriate referrals.
Response rates were extremely high, with (of 19,840 eligible individuals) 91% completing an individual interview, 97% completing a household interview, and 80% consenting to having their blood drawn (88% of those interviewed). The final sample sizes for analysis were 9691 households, 17,940 individual interviews, and 15,853 blood draws. Results were weighted by age and sex, but the reported findings did not reflect a full multivariate analysis, which is still in progress.
HIV and HSV prevalence
Nationally, 7.1% (95% confidence interval [CI], 6.5 to 7.8) of adults aged 15 to 64 were found to be HIV-positive – equivalent to 1.3 million Kenyans – with no statistically significant difference from the 2003 estimates. As in 2003, prevalence was higher among women than men (8.4% vs 5.4%, p
Prevalence was 3.8% for young people aged 15 to 24 years, 9.8% for people aged 25 to 49 years, and 5.0% among those aged 50 to 64 years. Infection was more common in women than men up until the age of 35.
Prevalence varied widely by province, from 0.8% to 14.9%. Prevalence was 3.4 times higher in uncircumcised than in circumcised men (13.2% vs 3.9%, p
HSV-2 prevalence was 35.1% overall and 80.7% among those infected with HIV (p
HIV testing and awareness
HIV testing nearly doubled in men aged 15 to 49 since the KDHS survey in 2003, with 25.6% reporting that they had ever been tested, versus 14.3% in 2003. Testing in women in the same age group tripled, from 13.1% in 2003 to 44.6% in 2007.
However, of all respondents, 63.5% still said that they had never been tested. Among HIV-positive respondents, 16% knew they were positive, 28% reported being uninfected based on their last test, and 56% had never been tested – a total of 84% of HIV-positive respondents who did not know that they were HIV-positive. These figures are comparable with other study findings in sub-Saharan Africa.
Among HIV-infected people who were married or cohabitating, 43.8% had an uninfected partner. The investigators estimated that 6% of all couples (350,000 couples) in Kenya were serodiscordant. Over three-quarters of all partnered respondents (77%) did not know their partner's HIV status.
A CD4 cell count of less than 250 cells/mm3 was taken to designate eligibility for ART, according to Kenyan guidelines.
There was an enormous gap in treatment use based on knowledge of HIV status. Treatment use was very high among HIV-positive respondents who knew their HIV status, but as most did not, the majority were not taking appropriate treatment. Among those aware of their status, 75% were taking cotrimoxazole and 92% of those eligible for ART were receiving it. Among all HIV-infected adults, however, cotrimoxazole coverage was only 12% and ART coverage was 39% among those eligible. Fifty-seven percent of those eligible for ART were not receiving it because they did not know their HIV status, and an additional 4% were not receiving it despite knowing their status.
Mohammed concluded that there does not appear to have been a significant increase in Kenyan HIV prevalence since 2003, and that testing rates have increased dramatically since that time. However, lack of diagnosis is still a major barrier to accessing prevention, care and treatment, and expansion of testing coverage "is now a priority," Mohammed said. "You cannot do anything to improve your health if you do not know that you are HIV positive."
Due to widespread lack of awareness of partner status, partner testing should also be a core component of care programmes, he added.
Mohammed I et al. HIV prevalence and unmet need for HIV testing, care and treatment in Kenya: results of a nationally representative survey. Sixteenth Conference on Retroviruses and Opportunistic Infections, Montreal, abstract 137LB, 2009.