Friday, December 10, 2010

What We Don't Know Can Hurt More Than What We Think We Know

Since HIV was first identified in the early 1980s, there have been three major trends in sub-Saharan African epidemics. The first is that about ten or more years after the virus began to spread, rates of transmission peaked and started to decline. The second is that after another ten years or so prevalence declined rapidly because of high death rates. The third is that prevalence flatlined, with deaths being replaced by new infections.

The question of why the virus started to spread rapidly in the first place has never been addressed adequately. It continues to be assumed that its spread was something to do with 'unsafe' sexual behavior, despite there being no evidence that credible levels sexual behavior could ever explain the massive transmission rates found in many countries. Nor has there been any evidence that levels of unsafe sexual behavior have ever been higher in high prevalence countries.

As to why transmission rates peaked and declined after a period, this has not been addressed either. Researchers seem to hope that no one will notice this gap in their knowledge. Not only is there no evidence that sexual behavior changed radically at around the time the virus started to spread, but nor is there evidence that some earlier increase in unsafe sexual behavior was subsequently reversed. HIV prevention programs, such as they were, didn't come along till much later and most of them had little impact.

Many countries where prevalence rates never went above 1% are seeing the same flatlining. Others are experiencing increases, including some Eastern and Central European countries, some Asian countries and some developed countries. Only those with exceptionally high rates of HVI transmission, all in Southern Africa, are seeing significant drops in prevalence. This is due to high death rates and reflects the stage that epidemics there have reached. HIV arrived in these countries relatively late.

Hordes of HIV-related papers have been published, most of them concentrating on possible links between sexual behavior and HIV rates. Some find correlations and these are held up as 'proof' that the virus is mainly transmitted sexually. Some research has noted a lack of such correlations and a lot of work has gone into trying to explain these findings away. And only a small amount of research has gone into non-sexual HIV transmission.

The lack of research into non-sexual HIV transmission is inexplicable, as is the level of contempt that the research that has been carried out appears to receive. No amount of research into sexual transmission will obviate the fact that non-sexual transmission has always played a part in the pandemic, a huge part in African countries. High correlations between levels of sexual behavior and levels of HIV prevalence are irrelevant to non-sexual transmission.

Ignoring non-sexual transmission of HIV has very serious consequences. The virus continues to be transmitted in health facilities and other places, unnecessarily and avoidably. People take risks that they don't even know are risks, such as attending an ante-natal clinic when pregnant and visiting an STI (sexually transmitted infection) clinic when in need of a sexual health checkup. No matter how vigilantly they apply all they hear about safe sex and protecting themselves against sexual transmission of HIV, this will never protect them from non-sexual transmission.

Currently, a lot of money is being poured into research into various technologies to reduce sexual transmission of HIV. These include microbicides, pills and various strategies. But much of this research will be invalid and probably unethical if it fails to factor in the possibility of non-sexual HIV transmission. The HIV pandemic may continue to flatline but it will not just go away. And there is always the possibility that the conditions, whatever they were, which resulted in rapid transmission rates seen in the early stage of the pandemic will return.


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