The World Health Organization (WHO) describes the Human Immunodeficiency Virus (HIV) as a
retrovirus that infects cells of the host’s immune system and destroys or impairs their function. Acquired
Immune Deficiency Syndrome (AIDS) is the disease caused by infection with the HIV. AIDS results in
severe damage of the body’s immune system causing vulnerability to life-threatening infections and
tumors (1). Heterosexual sex between an HIV infected person and uninfected partner is the main mode
of HIV transmission in many sub-Saharan African (SSA) countries (2;3). The WHO and The Joint United
Nations Programme on HIV/AIDS (UNAIDS) joint report on global HIV epidemic showed that nearly twothirds
of the 34 million people infected with the virus resided in SSA in 2010 (4). Kenya is among the
countries with high HIV prevalence in SSA. The Kenya AIDS Indicator Survey (KAIS) conducted in 2007
showed that HIV prevalence among adults aged 15-64 years was 7.1% (5). A similar population-based
survey conducted five years later showed a decline in HIV prevalence to 5.6% (6). The two surveys
showed that Nyanza province in western Kenya had the highest HIV prevalence in Kenya with 14.9% and
15.2% of adults aged 15-64 years having HIV-infection in 2007 and 2012, respectively (5;6).
In order to plan for effective interventions to respond to the HIV epidemic, it is necessary to understand
the socio-demographic, behavioral and biological factors associated with the disease. Various sources of
data including routine statistical summaries, surveys, surveillance, operational research and
mathematical modeling are used to monitor the distribution and trends in the epidemic in response to
prevention and treatment programs. UNAIDS and WHO have developed guidelines for measuring HIV
prevalence in population-based surveys (7). The KAIS protocols were developed based on the
UNAIDS/WHO guidelines to provide HIV prevalence data as well as factors associated with HIV infection
in Kenya (5;6).
KAIS is a household survey that entails interviewing eligible and consenting respondents from sampled
clusters of households. Blood samples are collected from consenting participants for central testing in
the laboratory to determine HIV prevalence. Individual participants who wish to know their HIV status
can collect their results at the nearest clinic six weeks after blood sample collection, or participate in a
voluntary home-based HIV counseling and testing. Those confirmed to be HIV-infected are referred for
HIV care and treatment services. KAIS also provides critical data on access to HIV prevention, care and
treatment services, respondents’ perception of risk for HIV infection, risk factors for HIV infection and
co-morbidities – including sexually transmitted infections.