Date Published: August 17, 2017
Author(s): Bonaventura C. T. Mpondo, Daniel W. Gunda, Semvua B. Kilonzo.
HIV remains a public health concern in Tanzania and other Eastern and Southern African countries. Estimates show that there were about 1.4 million people living with HIV in Tanzania in the year 2013. HIV is a generalized epidemic in Tanzania with heterosexual transmission being the main route of transmission. Recently, however, there has been growing concern on the potential role of the key populations in HIV epidemic in the country. Studies done have shown significantly higher HIV prevalence in these populations compared to the general population. These studies have also reported high risky behaviors among members of these populations. This review aims at discussing the possible role of the key populations in the HIV epidemic in Tanzania.
HIV remains a public health concern in many sub-Saharan African countries including Tanzania. In the year 2013, it was estimated that there were a total of 1.4 million people living with HIV in Tanzania . The national prevalence among people aged 15–49 years in Tanzania was estimated to be 5.1% in 2011, which is a drop of approximately 2% compared to the year 2003 . In Tanzania, HIV is a generalized epidemic affecting both urban and rural populations with approximately over 80% of HIV infections resulting from heterosexual transmission .
In April 2014, the Ministry of Health of Tanzania together with the Tanzania Commission for AIDS (TACAIDS) met with stakeholders to estimate the HIV prevalence and population estimates of the key populations in mainland Tanzania. The stakeholders reviewed the existing evidence and identified the limitations and knowledge gaps in the studies. They then used a Delphi method  to come to a consensus on the estimated population size and HIV prevalence on the three groups of key populations: female sexual workers, men who have sex with men, and people who use/inject drugs .
The prevalence of HIV in general population in Tanzania is estimated to be about 5.1%; however, there are geographical variations with high burden in the Southern Highland zone of the country  (Figure 1). Several studies have been done to determine the drivers of HIV epidemic in Tanzania. A survey that was conducted by the National Institute for Medical Research in 2009 revealed that early age for sexual debut, having multiple sexual partners, extramarital sex, and low knowledge on condoms were factors associated with HIV risk in Tanzanian communities . In this survey, 85% of the respondents reported to have had their sexual debut between the ages of 10–19 years. Early sexual debut has been reported to be a predictor of having multiple sexual partners later in life . Up to 25% of the respondents reported that they did not know where to get the condoms; extramarital sex was reported in 79% of the respondents. The conclusion from this survey was that high levels of multiple and concurrent sexual partners, intergenerational sex, and transactional sex were among the drivers of HIV epidemic in Tanzania.
HIV prevalence has been reported to be higher among the members of the key populations compared to the general population in Tanzania just like in other countries. As reported earlier, members of these populations have high frequency of partner change; with the high HIV prevalence, these form a “core group” in the transmission model described by Anderson . According to the model, sexual partners of these individuals will serve as a “bridging population” between the members of the core groups and the general population (Figure 2). Members of the core groups and their sexual partners have been shown to be the drivers of HIV epidemic in many parts of the world . Members of the key population, therefore, together with their sexual partners could be contributing to the epidemic in Tanzania.
Tanzania through scaling up HIV interventions has managed to significantly reduce the prevalence of HIV in the general population. The prevalence of HIV has been on the decline; in 2003/2004, the prevalence was estimated to be 7%. The survey done in 2007/2008 found the prevalence to be 5.7% and that in 2011/2012 found it to be 5.1%. However, the prevalence among the KPs has been found to be disproportionately high. The country therefore saw the need to have interventions among the KPs and developed a national guideline that stipulates the comprehensive package of HIV interventions for key populations . The guidelines aimed at increasing access to both health-related and social services among the members of the KPs in order to minimize HIV transmission in these vulnerable and at risk groups.
Members of key population have higher rates of HIV in Tanzania compared to the general population. Risky sexual behaviors have been reported to be common in these populations; interactions with the general population increase the chance of transmission of HIV to the general population. Interventions to minimize HIV prevalence and transmission risk in these populations such as promoting and providing condoms for MSM and FSW, promoting the use of water-based lubricants for MSM, screening and treating STIs, harm-reduction techniques for IDUs (e.g., needle syringe exchange programs), and HIV counseling, testing, and early treatment initiation are important measures to prevent HIV transmission in Tanzania. The country therefore needs to lay stress on the need for HIV prevention, care, and treatment among the members of the key populations.