Profile of Hepatitis C & Injection Drug Use in Canada

Considerations for Intervention

In 1994, the Canadian Laboratory Centre for Disease Control (LCDC) held a national meeting on the prevention and control of HCV. This was followed by a conference in 1998 (Hepatitis C: Prevention and Control. A Public Health Consensus) intended to review the present state of knowledge and action with regard to the public health aspects of HCV. With respect to reaching IDU populations, the following conclusion was made:

Despite some efforts targeted at injection drug users (IDUs), the involvement of public health in Canada has not yet had a measurable impact on the hepatitis C epidemic in this group. There has been piggy-backing onto existing HIV/STD programs, which themselves are not adequate, but these cannot be expected to take into account the special characteristics of the HCV epidemic (LCDC, 1999, pg. 15).

This conclusion is consistent with the research findings reviewed in this report.

As expressed by researchers in Australia (Crofts et al., 1997; 1999; Van Beek et al., 1998), if the sharing of needles and syringes were the major mode of transmission of HCV, there would have been a decline in rates resulting from the provision of needle exchange programs since the late 1980s. Analyses reveal a decline in HIV, but not HCV. For instance, the prevalence of HCV among people who inject drugs is about 65% whereas that of HIV is less than 3%; incidence is about 15% per year for HCV and less than 1% per year for HIV.

A number of factors have been identified that help explain the high rates of HCV infection among people who inject drugs, and the relative ineffectiveness of existing HIV harm reduction strategies in reducing rates of HCV infection. First, compared to HIV, HCV is more easily transmitted through blood-to-blood contact, and infection is acquired earlier after initiation of injection drug use (Crofts and Aiken, 1997; Crofts et al., 1999; Tranchina, 1998; Wodak,1997). Minute amounts of blood may be sufficient to transmit HCV, so the risk associated with the sharing of drug equipment may be higher than that for HIV. As an indication of the potency of the virus, on average, HCV is 10 to 15 times more infectious by blood-to-blood contact than is HIV (Heintges and Wands, 1997; Liddle, 1996; Mather and Crofts, 1999). This is not to suggest that HIV prevention strategies such as needle exchange programs are unwarranted, but using current practices, they are not enough.

Videotapes of groups of individuals injecting drugs reveal many opportunities for exposure through blood contaminating equipment other than needles and syringes. This includes swabs, spoons, water vials and tourniquets, as well as surfaces in the immediate environment such as countertops. There are also various injection practices that increase the risk of transmission (Riehman, 1996). One practice, called 'booting', draws blood from the user's arm, mixes the drawn blood with the drug already contained in the syringe, and then re-administers the blood/drug mixture into the vein. Traces of blood will remain in the needle and syringe, thereby placing other users of the equipment at risk. In another practice, called 'frontloading' or 'backloading' the drug is mixed in one syringe, and then the mixture is divided by squirting some of the solution into one or more additional syringes. Although the needle is not shared, HCV can be transmitted if the syringe used for mixing has been previously contaminated. Therefore, encouraging drug users to adopt non-injecting routes of administration (sniffing, smoking, snorting or swallowing) may be another way for achieving HCV control among persons who inject drugs (Wodak, 1997).

The second important factor affecting rates of HCV infection is drug of choice. Cocaine is the drug of choice among many Canadians who inject drugs. Because cocaine is metabolized very quickly in the body, it requires far more frequent injections to maintain its effects. People who inject cocaine inject as often as twenty times a day, increasing the problems associated with obtaining clean needles and sharing contaminated needles (McAmmond and Associates, 1997).

Background viral prevalence is the third critical factor in the spread of HCV (Crofts et al., 1999). HCV prevalence is now so high among populations that inject drugs that even very occasional sharing of needles and syringes carries an extreme risk of infection. With a low prevalence virus such as HIV, high-risk behavior must be far more frequent and prevalent to sustain continued spread of infection. The implication is that control of the HCV epidemic will require more intense concentration on reducing needle-sharing and other risky behavior than was required to reduce the incidence of HIV.

Some of the research reviewed clearly shows the need for prevention efforts targeted at people who are just beginning to inject drugs, and those who are contemplating injection. For instance, van Beek et al. (1998) noted the extremely high incidence of HCV among participants less than 20 years of age in Australia. In the study conducted by Chang et al. (1999) in Taiwan, the steepest trajectory in HCV infection occurred within the first four months of IDU. These findings highlight the importance of early risk reduction and prevention interventions in reducing HCV infection rates. A major barrier, of course, is the difficulty in reaching this population. There is a clear need for research that can lend understanding to the nature of this group in terms of methods to identify new users and those contemplating IDU, and the types of messages and strategies that can effectively curb risky drug using behaviors.

Another important target group is the prison population. Prison populations are unique in that they represent a focused concentration of individuals at risk for contracting or spreading HCV. For instance, more than four-fifths (81%) of users of injection drugs in Toronto have been incarcerated since they began using intravenously (Millson et al., 1995). In the United States, it is estimated that 30-40% of the 1.8 million inmates in the US are infected with HCV (Reindollar, 1999). Not only is the risk of HCV exposure great within the confines of the prison, but this population also represents a serious risk to the community at large following their release. Future efforts directed at implementing education, policies, and procedures for the prevention and treatment of HCV in correctional populations in Canada are imperative.

Other at-risk populations that were identified include street-involved youth, women and Aboriginal people in Canada. The unique circumstances and needs of each of these groups will have to be incorporated in future prevention and intervention strategies if they are to be effective.

In an examination of IDU among street-involved youth in Toronto, Adlaf, Zdanowicz and Smart (1996) found that for many youth, drug use was symptomatic of family dysfunction and a hazardous street environment. Unless youth are able to remove themselves from street culture, success of intervention is low. The authors state that success may be improved with a combination of services including substance abuse treatment and other counseling, aftercare programs and social supports such as welfare, improved housing, literacy and job training.

Although inconclusive, there is evidence to suggest that females are becoming involved in IDU at a younger age than males. For women who inject drugs, sexual or physical abuse may be a critical underlying factor. Another important consideration is their social networks, and the finding that women are less able to resist pressure by their male partners to share needles. An area in need of further investigation is the factors underlying initiation into IDU, and an examination of gender differences.

Aboriginal people in Canada have many social disadvantages that place them at greater risk of harmful involvement with drugs. These unique realities need to be understood and addressed in future efforts designed to prevent the spread of HCV in this population. Specifically, prevention strategies will need to take into account ethnocultural differences which may impact upon risktaking behaviour and HCV infection.

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