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Trends in Viral Infections in Quebec Among People Who Inject Drugs

The Joint United Nations Programme on AIDS (UNAIDS) and the World Health Organization (WHO) consider people who inject drugs a key population to help control the spread of sexually transmitted and blood-borne infections (STBBIs). Important STBBIs in this population include HIV and hepatitis C virus (HCV). These viruses (and other microbes) can be transmitted when equipment (needles, syringes and so on) used by one person to inject drugs is reused by another person.

A team of researchers in Quebec established a network called SurvUDI. This network recruits people who use drugs for periodic surveys. The surveys ask participants about behaviours related to drug use. Participants also undergo screening for HIV and HCV.

The data from periodic surveys helps to keep track of trends in infections among the population of people who use drugs. The data can be used to evaluate and adapt harm reduction programs and the planning and delivery of services to help improve the health of people who use drugs. The information from the surveys complements existing public health measures to monitor trends in STBBIs.

According to the Quebec researchers, the participants in their research are generally “hard-to-reach [and] mostly out of treatment (for substance use disorders).”

In their latest report, researchers with SurvUDI focused on data collected from nearly 16,000 participants between the years 1995 and 2020. They found that the rate of new HIV infections decreased over time. The rate of new HCV infections, however, initially decreased and then stabilized. They also found changes in behaviours related to drug use.

Study details

SurvUDI was established in 1995 and most participants were recruited from sites where harm reduction services were provided. Such services included the provision of new syringes/needles and supervised drug consumption. According to the researchers, other places of recruitment included “drop-in centres, detention centres, detoxification clinics, STI clinics and rehabilitation programs.”

During surveys, participants provided oral fluid samples. The samples were shipped to Laboratoire de santé publique du Quebec, where they were analysed for antibodies to HIV and HCV. Note that the presence of antibodies to HCV indicates that at some point in the past a person was exposed to this virus; it does not reveal whether the infection has been resolved or is active. To uncover active HCV infection, analysis of blood samples for the genetic material of this virus is necessary.

A brief average profile of participants upon entering the study was as follows:

  • 75% of participants were male and 25% were female, at birth
  • age – 37 years
  • nearly 40% had unstable housing
  • exchanged sex for drugs: women – 33%; men – 7%

Results

Over the course of the 25 years of the study, the researchers found different trends:

New HIV infections

The rate of new HIV infections fell substantially, by more than 12-fold.

New HCV exposures

Initially, the proportion of people with antibodies to HCV fell between 1998 and 2011. However, after 2011, exposures to HCV stabilized.

Trends in behaviours related to drug use

Reports of using needles/syringes that had been used by other people fell significantly from 43% in 1995 to 12% in 2019.

Trends in specific drugs

Reports of using cocaine/crack via injection decreased significantly. Reports of injecting opioids other than heroin increased.

Reports of injecting amphetamine or methamphetamine increased significantly between 2001 and 2019. Beginning in 2001, reports of daily injection of amphetamine/methamphetamine increased significantly.

Factors linked to a positive test for viruses

According to the researchers, the following factors were linked to an increased risk of a positive HIV test result:

  • “injection with syringes already used by someone else”
  • cocaine as the most frequently injected drug

Factors associated with an increased risk of a positive HCV antibody test included the following:

  • injecting opioids other than heroin
  • injecting cocaine/crack
  • injecting 100 times or more in the past month
  • a history of injecting only in the past three years
  • reusing other people’s equipment for injections
  • exchanging sex for drugs

Bear in mind

Past research has found that outbreaks of STBBIs can occur and spread rapidly among groups of people who inject drugs.

Research with people who inject drugs can yield valuable insights to develop ways of preventing the spread of viral infections. The researchers stated that interventions with a proven track record of preventing the further spread of HIV include the following:

  • distribution of new needles/syringes
  • supervised injection services
  • treatment of substance use disorder (particularly the use of opioid substitution therapies such as buprenorphine and methadone)
  • providing education to the community
  • providing HIV treatment

The Quebec researchers noted work by American scientists who study the spread of viruses among people who use drugs. The American scientists stated: “Prevention of HIV epidemics among people who inject drugs should not be considered a once and done task, rather it should be considered as requiring continuous effort.”

The Quebec researchers stated that “it is particularly important to support the strength and availability of harm reduction programs and other effective evidence-based interventions and to adapt these programs to the needs of the population.”

For the future

The researchers noted that the provision of new needles/syringes likely helped to decrease the spread of HIV in the population studied. However, despite this decrease, they found that the incidence of reusing other people’s equipment remained relatively high in the latter years of the study. Research is needed to uncover why this is occurring and to find interventions that could help reduce the reuse of injecting equipment.

Studies are also needed to understand why rates of HCV exposure plateaued. The research team suspects that a high frequency of drug use and sharing injecting equipment may contribute to this.

The SurvUID network has recently implemented the collection and analysis of dried blood spots from participants. The blood spots are analysed for the presence of HIV and the genetic material of HCV (RNA). Future analyses using dried blood spots will hopefully become available.

Although the researchers found promising trends with decreased rates of new HIV infections and sharing of equipment for injecting drugs, rates of exposure to HCV have not decreased as much. This suggests that continued investment and strengthening of harm reduction services as well as monitoring of STBBIs in populations who inject drugs is needed.

By Sean R. Hosein

REFERENCE:

Blouin K, Blanchette C, Leclerc P, et al. HIV and HCV seroincidence, associated factors and drug use in people who inject drugs, SurvUDI network, eastern central Canada, 1995-2020. International Journal of Drug Policy. 2024; in press.

Source: CATIE