The evidence shown by the study by Pettifor AE et al throw up VERY important findings as we think about addressing the HIV risk of young people in Africa including Nigeria. As noted by Cate Hankins, the Scientific Adviser for UNAIDS, the comparison of two nationally representative surveys of young people by the authors of the study (see abstract below) starkly underscores that behaviour is not the sole determinant of HIV risk. South African young people had their first sex at a later age, have fewer sexual partners, and practise more safer sex than their American counterparts. How then can the more
than 10-fold difference in HIV prevalence be explained?
Cate's first thought goes to larger age gaps between sexual partners for the two countries. In South Africa, it is evident that women have older sex partners when compared to what is observed in the US. This means sexual mixing with older partners who can act as a bridge population to younger cohorts.... but there has to be more to it than that.
Also, in South Africa, male circumcision levels are far lower, herpes simplex 2 infection levels are higher, genital tract inflammation is higher, co-infections (tuberculosis, helminths) that can increase viral set points are more common, and the prevalence of the CCR5Δ32 coreceptor is lower.
As Cate rightly notes, social determinants such as gender power imbalances, poverty, coerced sex and rape, lack of youth friendly services, and stigma are likely playing important roles in the observed higher HIV risk observed amongst young persons in South Africa. There are however need for further studies to pull together how all these factors truly increase the risk of young persons to HIV.
The study by Pettifor et al was based on surveys conducted in 2003 (South Africa) and 2001-2 (USA) using somewhat different methodologies. Yet the findings give South Africa something to work with: they gradually are better understanding their epidemic and learning how to use their limited resources cost effectively to address their epidemic. Lets take a cue from this study and pull the multiple data we have in the country together - the many, many sentinel survey reports including the upcoming NARHS 2011 study – to learn more about the true drivers of the Nigerian epidemic. Lets pay more attention to the youths as efforts at cubbing the epidemic at this level will significantly drive down our incidence. Secondary data
analysis like the one done by Pettifor et al may well be most welcome for a country like Nigeria