The year is rushing to a close. World Aids Day is around the corner, and from our vantage point at SACEMA, 2011 is likely to be remembered as the year in which the concept of Treatment as Prevention (TasP) stopped being controversial. Few now seriously express doubt that effective ARV treatment cuts transmission, and debate has moved on to grapple with the questions of the extent, and over what time scale, this can translate into ‘game changing’ or ‘paradigm shifting’ scenarios.
SACEMA had the privilege of hosting an intense (Gates Foundation Funded) workshop of the international ‘HIV modelling consortium’, focusing on models of early treatment and their potential impact. Model scenarios were intriguing, debate was intense and constructive, and the prognosis was sobering. Treatment alone, at conceivable levels, given the current financial and infrastructural outlook, can curtail HIV incidence, but does not appear to open a road to HIV eradication. So we must accept that we must look to the ‘multiple prevention methods’ paradigm, new technologies, and cleverer healthcare systems if there is to be a future where HIV is a tolerable burden on those societies currently bearing the greatest impact.
An interesting theme worth watching, in the context of debate on interventions in the face of what will inevitably be a multi-generational epidemic, is the limits of orthodox discourse offered by various professional fraternities like ‘modellers’, ‘biostatisticians’, and ‘health economists’. The lengthy time scales, over which interventions and their consequences must play out, stretch all known, and perhaps all conceivable, formal methods to their limits, and demand that interpretation be a nuanced and careful technical execution. Should the model outputs be treated as crystal ball predictions, warnings, structural insights, or mere mental gymnastics. Perhaps it depends on the actual model in question, but formal predictions, in anything resembling the predictions which are the bread and butter of natural science, are hardly likely to be what epidemiological modelling is about.
On a narrower scope than steering us towards an HIV free generation, this edition of the SACEMA Quarterly epidemiological update offers, as usual, three perspectives on current challenges and recent progress. Carel Pretorius and Samuel Manda explore superficially very different, but, at a deeper level, analogous analytical problems relating to making sense of epidemiological ‘clusters’. It is tempting to attach interpretations to limited data which often does not support our pat conclusions, and we hope these pieces offer a useful view of on-going technical developments to support sound joining of the dots. A popular theme here at SACEMA, HIV incidence estimation, returns once again with a piece by Reshma Kassanjee, demonstrating how existing, previously neglected, specimens from the blood donation industry can be used to perform low cost, low risk, preliminary investigations into surveillance-application performance of new laboratory assays.