In clinical trials, the early initiation of HIV treatment (ART) stabilizes the immune system and significantly reduces the risk of developing AIDS-related infections and cancers. This benefit of ART is so profound that researchers increasingly expect that many ART users will live into their senior years.
Key to reaping the benefit of ART is achieving an undetectable level of HIV in the blood (viral load) and maintaining it through daily use of ART and regular checkups and laboratory monitoring. Clinical trials have found that ART users with undetectable viral loads do not pass on HIV to their sexual partners.
Harm Reduction in Brief
Viruses such as HIV and hepatitis B and C can be spread through the re-use of contaminated equipment when injecting drugs. Harm reduction is a term that refers to different ways to help reduce and/or alleviate the harm associated with substance use. A few examples of harm reduction activities include the following:
- provision of sterile syringes and needles
- psychosocial support
- opioid substitution therapy -- prescribed medicines, such as methadone, buprenorphine and in some cases pharmaceutical-grade heroin (diacetylmorphine)
- supervised injection sites
Compare and Contrast
Researchers at the British Columbia Centre for Excellence in HIV/AIDS along with other researchers in Vancouver have attempted to study the relative impact that ART, harm reduction or both can have on the spread of HIV. In their study, which is currently in press in the journal Lancet HIV, the harm reduction services consisted of the provision of sterile syringes/needles and the prescription of drugs such as methadone and buprenorphine. The researchers used health-related information collected in databases to develop computer simulations of the HIV epidemic in B.C. Researchers used the simulations to understand the effect of ART, harm reduction services or both on the province's HIV epidemic.
The researchers estimated that between 1996 and 2013, 3,204 new cases of HIV infection were prevented due to "the combined effect of the expansion of harm reduction services and ART coverage on HIV transmission via [sharing of syringes/needles]."
In one simulation, researchers assumed that ART would have zero impact on the spread of HIV among people who shared syringes/needles. They found that harm reduction services would have prevented about 77% of HIV infections that could have otherwise occurred. In another simulation where harm reduction efforts (distribution of sterile needles and opioid substitution therapy) were kept at relatively low levels, the researchers estimated that ART alone would have prevented 44% of HIV infections.
The provision of prescribed medicines (such as methadone and buprenorphine) helped people enjoy periods of good health, presumably because they were less likely to share syringes/needles.
As the researchers did their work via computer simulations, they cannot be certain about the precise impact of the different interventions on the course of the HIV epidemic among people who inject street drugs. However, the work of the B.C. researchers strongly suggests, in their own words, that "harm reduction services had a vital role in reducing [the spread of HIV] in B.C. and should be viewed as essential and cost-effective tools in combination implementation strategies to reduce the public health and economic burden of HIV/AIDS."
The researchers focused on limited elements of harm reduction because their impacts could be assessed relatively easily within the simulation since data were available on their deployment.
A noteworthy point is that the researchers assumed that among people who used ART and who injected street drugs, ART's ability to prevent the new HIV infections that occurred via sharing of syringes/needles was about 50%.
Results -- Impact of ART and Harm Reduction
Researchers found that the provision of both ART and harm reduction services prevented 3,204 people from becoming HIV positive between 1996 and 2013.
In one simulation, the researchers assumed that ART had no impact on the spread of HIV among people sharing syringes/needles. This assumption was made so that the researchers could try to isolate the specific impact of harm reduction. In that simulation they estimated that harm reduction alone would have prevented about 77% of HIV infections.
In a further focus on harm reduction services, the simulations revealed that the provision of sterile syringes/needles was likely responsible for preventing most new HIV infections. The use of opioid substitution therapy (methadone and buprenorphine) also helped to reduce some new infections (by about 15%). Furthermore, the researchers noted that this therapy was responsible for users spending time in improved health.