Have the explosive HIV epidemics in sub-Saharan Africa been driven by higher community viral load?

Publication Type:

Journal Article

Source:

AIDS (London, England), Volume 27, Issue 6, p.981-89 (2013)

Keywords:

2013, Center-Authored Paper, Clinical Research Division, December 2012, Public Health Sciences Division, Vaccine and Infectious Disease Division

Abstract:

OBJECTIVE:: The HIV epidemic has carved contrasting trajectories around the world with sub-Saharan Africa (SSA) being most affected. We hypothesized that mean HIV-1 plasma RNA viral loads (VL) are higher in SSA than other areas, and that these elevated levels may contribute to the scale of epidemics in this region. DESIGN AND METHODS:: To evaluate this hypothesis, we constructed a database of means of 71,668 VL measurements from 44 cohorts in seven regions of the world. We used linear regression statistical models to estimate differences in VL between regions. We also constructed and analyzed a mathematical model to describe the impact of the regional VL differences on HIV epidemic trajectory. RESULTS:: We found substantial regional VL heterogeneity. The mean VL in SSA was 0.58 log10 copies/mL higher than in North America (95% CI: 0.45 to 0.71); this represents about a 4-fold increase. The highest mean VLs were found in Southern and East Africa, while in Asia, Europe, North America, and South America, mean VLs were comparable. Mathematical modeling indicated that conservatively 14% of HIV infections in a representative population in Kenya could be attributed to the enhanced infectiousness of subjects with heightened VL. CONCLUSION:: We conclude that community VL appears to be higher in SSA than in other regions and this may be a central driver of the massive HIV epidemics in this region. The elevated VLs in SSA may reflect, among other factors, the high burden of co-infections or the preponderance of HIV-1 subtype C infection.