Studies from Lawson Health Research Institute and Western University have found for the first time that HIV can be transmitted through the sharing of equipment used to prepare drugs before injection and that a simple intervention – heating the equipment with a cigarette lighter for 10 seconds – can destroy the HIV virus, preventing that transmission. The findings, used to inform a public health campaign called ‘Cook Your Wash,’ have helped reduce rates of HIV transmission in London, Ontario.
The two studies were initiated in 2016 to address a public health emergency in London, Ontario when HIV rates amongst injection drug users more than doubled. “This outbreak occurred despite London having Canada’s largest per capita sterile needle and syringe distribution program, a strong opiate substitution therapy program and a multidisciplinary HIV clinic,” says Dr Michael Silverman, Lawson associate scientist and chair/chief of infectious diseases at the Schulich School of Medicine & Dentistry, Western University, London Health Sciences Centre and St Joseph‘s Health Care London. “We knew there must be a novel method of HIV transmission at play.”
From August 2016 to June 2017, the research team interviewed 119 injection drug users to understand their injection behaviours and risk for HIV. They discovered that those who shared equipment used to prepare drugs for injection were 22 times more likely to contract HIV than those who did not, despite not sharing needles or syringes.
The equipment includes a metal ‘cooker’ used to dissolve drugs in water and a filter used to draw the mixture, known as ‘the wash,’ into the syringe. Injection drug users reported reusing the equipment when consuming controlled-release hydromorphone, one of the most commonly injected opioids.
“Controlled-release hydromorphone is expensive and difficult to dissolve. After the first wash, large amounts of the drug remain in the equipment which is then saved, shared or sold for future use,” explains Dr Sharon Koivu, associate scientist at Lawson and associate professor at Schulich Medicine & Dentistry. “While people know not to share needles, some use their own needle multiple times allowing for contamination of the equipment.”
The team took their findings back to the research laboratory. They confirmed that, on average, 45% of the drug remains in the equipment after the first wash. They not only confirmed the HIV virus can be transmitted between needles, cookers and filters, but also discovered that controlled-release hydromorphone has properties that promote survival of the virus.
“The slow release properties in the drug can unfortunately stabilise the HIV virus,” says Dr Eric Arts, chair of the department of microbiology and immunology at Schulich Medicine & Dentistry. “For the first time, we were able to demonstrate that sharing equipment could lead to the type of HIV outbreak we observed in the community.”
The team discovered that when the cooker is heated with a cigarette lighter for approximately 10 seconds, or until the wash bubbles, the virus is destroyed. They termed the technique ‘cook your wash.’
They also confirmed that heating the cooker did not impact drug concentration. “We had to make sure that cooking your wash would not change the amount of drug being drawn into the syringe,” notes Silverman. “If too much drug was released, it could lead to overdoses. If any drug was burnt off or lost, the intervention would not be accepted by persons who inject drugs.”
Partnering with local community organisations like the Middlesex-London Health Unit and Regional HIV/Aids Connection, ‘Cook Your Wash’ was launched as a public health campaign.
“The ‘Cook Your Wash’ campaign is one of the most exciting things to happen in our community,” says Koivu. “We learned from persons who inject drugs, took that information to the lab to develop a solution and then brought that solution back to the community in record time.”
Silverman adds that local rates of new HIV cases fell dramatically after the introduction of the campaign. “It wasn’t the sole reason for the reduction in HIV rates as other interventions were also introduced, but the timing suggests it was part of the solution.”
The studies build on previous research that shows sharing equipment can lead to the transmission of hepatitis C and controlled-release hydromorphone can promote the survival of bacteria that can cause endocarditis, which is an infection of the heart valves.
The team hopes this research can be used to inform understanding and interventions in other centres facing HIV epidemics amongst persons who inject drugs. “We hope our findings can be used to reduce the incidence of HIV transmissions even further and that, one day, society will be HIV free,” says Silverman.
Background: London, Canada experienced an HIV outbreak among persons who inject drugs (PWID) despite widespread distribution of harm reduction equipment. Hydromorphone controlled-release (HMC) is the local opioid of choice. Injection drug preparation equipment (IDPE; i.e., cookers, filters) are often shared and reused due to the perception that there is residual HMC in the IDPE after use. The purpose of this study was to investigate the mechanisms of HIV transmission in this context.
Methods: Residual hydromorphone, (controlled-release or immediate-release), remaining in the IDPE, was measured with liquid chromatography–tandem mass spectrometry, in conditions replicating PWID use. HIV was added to IDPE in the presence HMC, hydromorphone immediate-release, or microcrystalline cellulose (an HMC drug excipient). HIV viral persistence was measured by reverse transcriptase activity and infectivity of indicator Tzm-bl cells.
Results: 45% of HMC remained in the IDPE following the first aspiration of solution, with no change after heating. HIV persistence and infectivity were preserved in the presence of HMC, and less so with microcrystalline cellulose. Heating the IDPE rapidly inactivated HIV.
Conclusions: Sharing of IDPE is a potential means of HIV transmission. HMC encourages IDPE sharing due to the residual drug in the IDPE, and the HMC excipients preserve HIV viability. Heating IDPE prior to aspiration of the opioid may be a harm reduction strategy.
Laura Ball; Colin Venner; Rommel Tirona; Eric Arts; Kaveri Gupta; Joshua Wiener; Sharon Koivu; Michael Silverman