Tanzania HIV/AIDS and Malaria Indicator Survey ... - Measure DHS

HIV PREVALENCE 99.1 INTRODUCTIONPrior to the 2003-04 Tanzania HIV/AIDS Indicator Survey (THIS), national HIV prevalencewas estimated using prevalence from blood donors and sentinel surveillance among pregnant womenattending selected antenatal care (ANC) services. Prevalence estimates really began in 1990 when 24ANC sites were established for HIV surveillance in 11 regions. In 2005-06, surveillance of HIVamong ANC attendees had increased to 90 ANC sites in 15 regions. Results from that round of ANCsurveillance data were analysed and used together with data from the 2003-04 THIS to estimate theprevalence of HIV among the Tanzania population. The 2008 round of sentinel surveillance of HIVamong pregnant women is being collected from 134 ANC sites in all 21 regions in MainlandTanzania.Another source of information that was sometimes used in estimating HIV prevalence rates inthe general population was data collected from blood donations. As a matter of policy, there ismandatory screening of blood that is used for blood transfusion. Data from this source were availablethroughout the country. Because for some years this was the only information available at the subnationallevel, it has been used as a proxy for HIV infection rates in those areas.From July 2007 to April 2008, Tanzania carried out the National Voluntary HIV TestingCampaign in all parts of the country. During this period, over 4 million Tanzanians were tested forHIV and results were made available to those tested. In some regions and districts, HIV test resultsfrom this campaign are being used to estimate the rate of HIV infection in those localities.While the rates of HIV infection from the above-mentioned sources are important and arebeing used in various settings, they cannot be used as a reliable estimate of the HIV prevalence ratefor the Tanzania population. The ANC data do not capture information on HIV prevalence in nonpregnantwomen, nor in women who do not attend clinics for ANC. Pregnant women are more at riskfor HIV infection than women who may be avoiding both HIV and pregnancy through the use ofcondoms or women who are less sexually active and therefore less likely to become pregnant orexpose themselves to HIV. In addition, there may be biases in the ANC surveillance data becauseHIV infection reduces fertility and knowledge of HIV status may influence fertility choices.Moreover, ANC data do not include socio-economic characteristics that may facilitate HIV infection.Finally, ANC data are sex selective; therefore, the rates among pregnant women are not a proxy formale HIV rates.Although blood donor data have been used widely in various areas, they have limitations.First, before the introduction of the National Blood Transfusion Services (NTS) in Tanzania, mostblood donors were relatives of the patient and hence were not representative of the general population.Secondly, it is likely that those who suspect that they might have contracted HIV do not volunteer todonate blood for fear of being tested and/or potentially infecting the patient. While the introduction ofthe NTS eliminated dependence on relatives of patients for blood donations, data from this sourceshould not be used to estimate the prevalence of HIV in the general population. This is because NTSaims at obtaining blood of the highest quality and does a lot of screening during recruitment ofdonors; hence, NTS has a very low rate of HIV infection, which underestimates the actual prevalencein the general population.The National Voluntary HIV Testing Campaign, which took place throughout the country,was voluntary. People came for testing by choice and no scientific methods were applied to obtaininformation about the clients.HIV Prevalence | 109