A switch to a cheaper injectable illicit drug led to a major outbreak of HIV infection in Tel Aviv, Israel, and should serve as a warning signal for other cities with apparently stable HIV epidemics among people who inject drugs, Israeli researchers warned last week at the 14th European AIDS Conference.
Professor Michel Kazatchkine, the UN Secretary General’s Special Envoy on HIV in eastern Europe and central Asia, also warned the conference of the potential for new epidemics of HIV in people who inject drugs, following recent HIV outbreaks in Romania and Greece driven by the availability of new substances.
HIV prevalence among people who inject drugs in Israel has been stable for the past decade, as a result of government-funded needle and syringe exchange programmes, and opioid substitution therapy. Crusaid Kobler AIDS Center, Tel Aviv Sourafsky Medical Center, had observed no cases of primary HIV infection in people who inject drugs among 130 cases of primary infection diagnosed by the clinic.
Yet in June 2012, Tel Aviv Medical Center Laboratory noticed a disturbing phenomenon. Five primary HIV infections had been diagnosed in people who inject drugs in two months, and over the following year a further 40 cases were identified. The majority of these cases were diagnosed following admission to hospital with severe bacterial infections – bacteraemia, pneumonia or endocarditis – and every person diagnosed with HIV was also found to have hepatitis C.
In every case the patient was a long-term heroin injector who had been using the needle and syringe exchange on a regular basis.
But in early 2012, a large number of heroin injectors began switching to a cheaper injectable substance, known as 'hagitat' in Israel, a cathinone derivative also known as 'bath salts', injected in combination with the opioid substitute buprenorphine. Cathinone derivatives include mephedrone, a popular 'club drug'. Many synthetic cathinones are not controlled substances under drug enforcement legislation, and new variants are emerging all the time.
Everyone who became infected with HIV during the 2012-13 outbreak had switched to injecting 'hagitat'.
In contrast, none of the stable drug users who continued to inject heroin became infected with HIV.
Cathinone derivatives are synthetic amphetamine-like stimulants that induce euphoria, increased sex drive and sociability, as well as delirium and violent, erratic behaviour. They can also cause cardiac arrhythmias, hyperthermia, rhabdomylosis or death, and are associated with a high frequency of severe bacterial infections if injected.
Cathinone derivatives were adopted rapidly by drug users in Tel Aviv because they are cheap in comparison to heroin, but the drug effect is short, requiring up to 30 injections each day. Whereas heroin injecting is a relatively private activity (needle sharing takes place with only one or two people in most cases), cathinone injecting tends to be highly social. Furthermore, whereas heroin injecting requires the drug to be heated in a cup or spoon before being drawn up into the syringe, cathinone derivatives must be dissolved in cold water to avoid inactivating the drug. The lack of heating is likely to remove any sterilising effect that heating might have during heroin injecting, said Dr Eugene Katchman of Tel Aviv Sourafsky Medical Center. A very high rate of syringe re-use and needle sharing occurs as a result of the high injecting frequency, Dr Katchman added.
Phylogenetic analysis of 30 outbreak isolates revealed that all drug users had been infected with HIV-1 subtype A/CRF01 AE, and suggested that all infections were linked to one originating isolate.
In an effort to limit the further spread of HIV, doctors from Tel Aviv Sourafsky Medical Center educated needle and syringe exchange programme staff and volunteers on the outbreak, and instituted an active screening programme among drug injectors who used the needle and syringe exchange.
Needle and syringe exchange staff launched an education programme among drug users, and also increased the supply of needles, syringes and sterile cups.
Everyone who tested positive for HIV was offered immediate antiretroviral treatment in order to reduce viral load and limit onward spread of HIV. Viral loads at diagnosis were high (a median of 181,000 copies/ml) and the median CD4 cell count was 560 cells/mm3.
A rapid, multidisciplinary response is required when shifts in drug use trigger a new outbreak of HIV among people who inject drugs, Dr Katchman told the conference.
References
Katchman E et al. An outbreak of primary HIV infection among injecting drug users in Tel Aviv, Israel, associated with changes in illicit drug use practices. 14th European AIDS Conference, Brussels, abstract PS11/4, 2013. View the abstract on the conference website.