There exists an ageless belief that science is a free-thinking environment where dedicated people happily share information about their work for the goodness and well being of Mankind. Sorry to disappoint the reader, but this is wishful thinking. Distributing and accessing peer-reviewed scientific information might become more difficult as commented elsewhere and for instance this post refers to scientific information available only to the “chosen one”, or those whose employer can afford to pay for it. But what is ironic, is that the subject of this post is itself one for which information is not only scarce but difficult to collect.

In today’s Lancet, Bradley Mathers and colleagues of the 2007 Reference Group to the UN on HIV and Injecting Drug Use published the result of their review of data available on HIV and Injecting Drug Use (IDU). 11 022 documents were identified by a systematic search of peer-reviewed, internet, and grey literature databases as well as data requested from UN agencies and international experts.

Data was available for 148 countries out of 200 considered, with very little information available for Africa (13 countries out of 47). Estimate of the prevalence of injecting drug was available for 61 countries and this was often derived from indirect prevalence estimates. Often sources and methods are not mentioned. Often too injection is reported without prevalence and based on data going several years back in time. Most notably, “about three-quarters of the country level estimates of injecting drug use were based on data sourced from the grey literature”.

Overall, little is know about a phenomenon whose prevalence is estimated between 0.02% and 5.21% (India and Azerbaijan respectively).

Data on HIV infection in IDU was reported in 86% of the countries for which injecting drug use was reported. And again “About 85% of the country-level estimates of HIV infection were based on data sourced from the grey literature.”

Prevalence of HIV infection among injecting drug users

HIV prevalence in IDU varied greatly both between and within countries and was estimated between 0.01% and 72.1% (Estonia). Within a country, such as Russia, HIV prevalence amongst IDU could vary between 0·3% in Pskov, 12·4% in Moscow, 32% in St Petersburg, and 74% in Biysk.

The researchers wrote that “extrapolating to all countries, we estimate that globally about 3·0 million (range 0·8–6·6 million) people who inject drugs might be HIV positive (table 7); the largest populations of HIV-positive injecting drug users were in eastern Europe, east and south-east Asia, and Latin America.”

Previous reviews dating back to 1998 identified a lower number of countries in which IDU was reported suggesting an increased number of IDUs with the caveat that it is difficult to compare reviews using different material and methods.

“Little is known about injecting drug use in sub-Saharan Africa, but a constellation of risk factors exist for the development of injecting drug use, as has occurred elsewhere, for example in central Asia.” And “because sub-Saharan Africa is a region with particularly high HIV-1 prevalence, with a range of social and biological risk factors having a role, the potential emergence of injecting drug use as an additional route of HIV transmission warrants serious attention.”

Despite its limitations this study reveals that a) very little reliable information is available about IDU, b) prevalence of IDU varies greatly within a country, c) there are even less data about HIV prevalence amongst IDU but d) higher HIV prevalence is nevertheless observed in most IDU population.

Because injecting drug is an illegal an stigmatised behaviour injecting drug users are rarely perceived worthy of compassion and have received little attention so far.

“The magnitude of the risk has not been met with an equally concerted investment in research to accurately quantify the problem.”

Another unoticed time bomb waiting to explode?

(article available upon “discreet” request and for personal use only)

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