Archive for the ‘Intravenous drug use’ Category

The risk network approach to HIV detection: something like contact tracing?

Friday, March 2nd, 2018

There has been considerable debate on the most effective and cost-effective means of accessing untested HIV- or STI-infected individuals. One frequently canvassed strategy is that of respondent driven sampling (RDS). This involves issuing suitable ‘seeds’ (e.g. recently diagnosed MSM) with coupons to distribute to others in their sexual or social networks.  Wei & Raymond (STI) in a recent study of black MSM in San Francisco compare RDS very favourably with time location sampling (TLS) as a method of recruitment of those most likely to be at risk. Similary, Rosenberg & Miller (STI) in a small study in Malawi observe the superior effectiveness of infected, over non-infected seeds in discovering untested individuals (31% vs. 11%). Much, of course, depends on the target group; so, for example, Weir & Chen (STI) find in favour of ‘venue-based’ sampling over RDS in the case of Chinese FSW.

Smyrnov & Friedman (S&F) report a Ukrainian intervention which used HIV-infected seeds to access networks of people who inject drugs (PWID) and other at-risk individuals over the period 2013-16, and resulted in 1,252 tests (Transmission Reduction Intervention Project, or TRIP). The intervention is a refinement of RDS which the researchers describe as a ‘risk network’ approach. Seeds – some recently-infected, others longer-term infected – recruit through networks that are relatively strictly defined (by comparison with normal RDS). Such networks are restricted to: persons with whom the seeds had performed sex or injected drugs; people present where this had taken place; those at small-sized venues frequented by these participants. The researchers then compare the outcomes of their own study (undiagnosed HIV-positive as a proportion of persons tested, and cost per person identified) with the outcome of a more traditionally conceived RDS trial amongst PWID in Odessa involving 400 persons, and a large (13,936) community-based ‘Outreach Testing’ programme, also amongst PWID.

The proportion of undiagnosed positives identified by TRIP (14.6%) was much higher than it was for the RDS (5%) or Outreach (2.4%). This gives odds rations for TRIP of 3.25 as against conventional RDS and 7.03 as against Outreach. Within TRIP the networks seeded by recently infected persons contained a greater proportion of undiagnosed positives (16.3%) than those seeded by the longer-term infected (12.2%). As for cost per HIV positive identified, this the researchers estimate at $250 for TRIP as against $387 for RDS and $653 for Outreach. They conclude that interventions prioritizing networks of the recently effected offer the most efficient way of detecting undiagnosed HIV positive persons.

On the face of it, the ‘risk-network’ approach looks rather like an enhanced version of the well-known practice in sexual health of contract tracing – a ‘contract tracing plus’. It may seem evident, but contact tracing has shown itself to be a very effective intervention (Rayment & Sullivan (STI)); perhaps it offers a basis on which to model larger-scale interventions. The study of S&F would at least suggest so.

Indiana State ban on Needle Share programmes faces challenge of an IDU-fuelled HIV spike

Monday, April 20th, 2015

In 2011 18.5% of HIV infections in the US were attributable to intravenous drug-use (IDU) – a significant proportion (Lansky & Wejnert (STIs)).  The issue of IDU fuelled HIV transmission has been brought forcibly to the attention of Americans in the last few weeks by the recent HIV outbreak in Scott County, Indiana, US.  This local epidemic appears to have been the result of the recreational use of the opiate, Opala. The number of infections has continued to rise, reaching a new peak of 130 this last week (Indystar/needle exchange; npr/Indiana’s HIV spike).

The effectiveness of public health interventions amongst IDU, including needle exchange programmes is well-established. Recent studies in Russia and East-European contexts (Vagaitseva & Demyanenko (STIs); Boci & Bani (STIs)), where IDU accounts for greatest proportion of infections,  have also come to very positive conclusions about their cost-effectiveness (Demyanenko & Vagaitseva (STIs).  They have also considered ways of improving uptake among drug-users (Boci & Hallkaj (STIs).  Sadly, in 23 states of the US – as in Russia and some East-European countries – traditional legal restrictions on needle exchange programmes remain in force (LawAtlas/US).  Indiana just happens to be one of these US states.  Its governor, who has had to authorize a short-term moratorium on the legal restriction of needle exchange in response to the outbreak, just happens to be Mike Pence, a republican who is known for his especially hawkish views on social issues (see “US Republicans prepared to put the poor at risk” (STI/blogs)) and favours continuation of the ban.

Needless to say, an order authorizing the temporary suspension of the restrictions on needle exchange was issued last month.  A needle-exchange programme has distributed 5,300 clean needles to drug-users since 8th April when it began its activities.

Unfortunately, however, the temporary suspension is due to expire on 25th April.  It also applies only to Scott County. Health experts are pushing legislators to allow needle exchange in neighbouring counties of Indiana, where high levels of HCV indicate a high risk of similar outbreaks.  On Monday, a joint Senate and House Legislative Committee will consider a measure, authored by Ed Clere, a representative from a neighbouring county, to authorize local public health and law enforcement authorities to work together to start their own need exchange programmes. But Governor Pence has threatened to veto the measure.  He declines to explain his position in public, but is said by Senate President, David Long, to believe that needle exchange programmes lead to greater drug use (News & Tribune/Indiana’s needle exchange bill).

IDU and HIV in the Middle East: a brief window of opportunity?

Tuesday, July 22nd, 2014

There are regions of the world where intravenous drug use (IDU) is known to have a key role in evolving HIV epidemics.  Information about IDU populations, on the basis of which to motivate and inform public health interventions, can be scant and of poor quality (STI/Aceijas & Hickman).  This deficiency is particularly important to address, given the possibility in some contexts of these populations serving as a bridge into other populations (STI/Reza & Blanchard; STI/Decker & Beyrer), and the practicality and cost-effectiveness of interventions that could make a difference (e.g. needle/syringe exchange programmes) (STI/Demyanenko & Vagaitseva; STI/Boci & Hallkaj).

The Middle East and North Africa (MENA) is among the regions of the world in which IDU might be expected to be a key epidemiological factor – given the availability and cheapness of drugs (US$ 4 per gram of heroine, as against US$ 100 in Europe).  But, as recently as 2005, the region was characterized as “as real hole in terms of HIV/AIDS epidemiological data” – let alone in terms of IDU HIV data.  STI/Reza & Blanchard in an alarming study of epidemiological bridging in Pakistan do not include other MENA countries among the epidemiological parallels to which they refer – perhaps because of the lack of data.

A recent systematic review by Mumtaz & Abu-Raddad (M&R) may go some way to addressing this need, but points to the importance of further research.  M&R review and synthesize data from sources (e.g. international and regional databases, and country-level reports) relevant to actual and potential HIV risk for IDU populations across 23 nations in MENA.  They estimate average IDU over the region at 0.24 per 100 adults, and HIV prevalence in these populations averaging 10-15% (both figures comparable with what we find in other regions).  Among the 10 (23) nations for which good evidence is available, 6 show concentrated epidemics suddenly emerging over the last ten years (Iran, Pakistan, Afghanistan, Egypt, Morocco, Libya), at national (Iran, Pakistan) or local (Afghanistan, Egypt, Morocco, Libya) level; 4-5 others show low level epidemics.

This study delivers a strong message.  Data from countries for which there is evidence of low level IDU HIV epidemics suggests “moderate HIV potential” (i.e. high levels of unsafe practices reflected in prevalence of Hepatitis C and other STIs).  The same, for all anyone knows, may also be true for those 13 countries for which the evidence is not available.  Pakistan saw rocketing levels of HIV (from near 0% to 23% in six months) following introduction of the infection into IDU populations.  Low prevalence countries, including those about which we know little, may have only a brief “window of opportunity” before they experience a comparable explosion of HIV among their own IDU populations.  This, according to M&A makes it imperative to conduct studies in those 13 countries, and to implement further rounds of surveillance in those for which there is already evidence, with a view to making timely and effective interventions.  M&A cite, as evidence of the patchy coverage of IDU by existing prevention services over the region, the very small proportion of the IDU population reporting ever being tested for HIV as indicated by studies conducted in Morocco and Pakistan.