HIV/AIDS Epi Update - May 2004

HIV and AIDS Among Youth in Canada

Introduction

At A Glance

Risk behaviour data on young Canadians show the potential for HIV transmission.

Street-involved youth, youth who inject drugs and young men who have sex with men are particularly vulnerable to HIV.

A wide range of prevention activities needs to be implemented to help minimize the risk of HIV transmission among youth.

Although youth (defined here as those aged 10 to 24 years) currently constitute a small proportion of the total number of reported HIV and AIDS cases in Canada, they are a group that has been greatly affected by the HIV/AIDS epidemic at a global level. According to the most recent UNAIDS report, an estimated 11.8 million people aged 15 to 24 years are living with HIV/AIDS, and half of all new infections worldwide are occurring among young people.¹ Youth, in general, are vulnerable to HIV infection as a result of many factors, including risky sexual behaviour, substance use (including injecting drug use) and perceptions that HIV is not a threat to them. Young Canadians require the necessary information and skills to help them to adopt and maintain behaviours that are protective against HIV. This Epi Update provides the most current information on the status of HIV and AIDS among Canadian youth. HIV-related risk behaviours in this population are also highlighted.

AIDS Data²

• As of June 30, 2003, there were 18,929 AIDS cases with information about age reported to the Centre for Infectious Disease Prevention and Control (CIDPC). Of these, 649 (3.4%) were among youth aged 10 to 24 years.
• As seen in Table 1, of the cumulative reported AIDS cases in youth aged 10 to 19 years, almost two-thirds of cases were attributed to recipients of blood and blood products. Among youth aged 20 to 24 years of age with AIDS, almost half were attributed to men who have sex with men (MSM), and 20% to heterosexual contact. Heterosexual contact includes sexual contact with a person at risk of HIV, origin from a country where HIV is endemic, and heterosexual contact as the only identified risk.

HIV Testing Data²

Data received from provincial and territorial HIV testing programs do not allow separation of the 10-14 and 20-24 year age groups before 1998, thus restricting the analysis of HIV test reports for youth.

• As of June 30, 2003, there were 50,332 positive HIV tests with information about age reported to CIDPC. Of these, 721 (1.4%) were among youth aged 15 to 19 years, and 13,083 (26.0%) were among individuals aged 20 to 29 years.
• Of all HIV positive test reports the proportion attributed to females varies considerably by age and is highest among adolescents and young adults. In 2002, females accounted for 38.6% of positive HIV test reports among those aged 15 to 29 years (196/508), a decrease from 44.4% in 2001 (194/437).
• In 2002, MSM, heterosexual contact and injecting drug use accounted for 41.9%, 35.0% and 17.5% respectively of reported positive HIV tests with known exposure category among those aged 20 to 29 years. Heterosexual contact and injecting drug use accounted for 63% and 32% of reported HIV tests with known exposure category among those aged 15 to 19 years (n = 19).
• A cumulative total of 675 positive HIV test reports had been received by June 30, 2003, for individuals less than 15 years of age. Of the 360 cases in this group with known exposure category information, perinatal transmission and exposure to infected blood or blood products accounted for over 90% of cases.

HIV Incidence and Prevalence among Youth

HIV prevalence and incidence information, in conjunction with HIV/AIDS surveillance data, are more useful than surveillance data alone for depicting the current magnitude of the HIV epidemic in various population subgroups. To date, a small number of Canadian studies have examined HIV prevalence or incidence among youth, although most research has involved higher risk populations:

• In the Vancouver Injection Drug User Study (VIDUS), the prevalence of HIV among injecting drug users (IDU) aged 24 years and younger during the period 1996-2001 was 17%. HIV incidence among participants in this age category was reported as 2.96 for males and 5.69 for females per 100 person years (PY).³
• Young Aboriginal IDU in BC have been shown to have a high HIV prevalence rate. In the VIDUS study, a comparison of young Aboriginal versus non-Aboriginal IDU (age 24 or under) revealed an HIV prevalence rate of 39% for Aboriginal IDU and 11% for non-Aboriginal IDU.⁴
• Further information from the VIDUS study has shown there to be a high prevalence of HIV/hepatitis C (HCV) co-infection. In a recent study, a sample of IDU aged 29 and under had a co-infection rate of 16%, while a further 53% were solely HCV positive and 3% were solely HIV positive.⁵
• In the Montreal Street Youth Cohort study (MSYC), participants between 14 and 25 years old have been observed since January 1995. HIV prevalence at study entry in the cohort was 1.4% (14 of 1,013 subjects). HIV incidence up to September 2000 was 0.69 per 100 person years.5 Among MSM participating in the Montreal Street Youth study in 2000 the prevalence of HIV was 4.9% and the incidence was 1.2 per 100 PY.^6,7
• An HIV prevalence of 0.25% was observed in the mid-1990s among young offenders aged 12 to 19 years in British Columbia, many of whom reported a history of injecting drug use.⁸
• Sentinel hospital surveillance of HIV infection in Quebec (early 1990s),⁹ a study of women seeking prenatal care in British Columbia (early 1990s)¹⁰ and a survey of youth from across Canada involved in an international exchange program (early to mid 1990s)¹¹ reported prevalence rates of 0.04% to 0.08% among young people aged 14 to 25 years. In a study in the late 1990s of women seeking abortions in Montreal, the prevalence of HIV among those aged 20 to 24 years was 0.0015%, and there were no infections detected among women under 20 years of age.¹² It should be noted that these latter studies involved relatively small, non-representative samples of youth; thus, a zero to very low HIV prevalence rate is not necessarily reassuring.
• In a recent study focusing on MSM aged 16 to 30 (Omega cohort in Montreal), seroprevalence rates of 19.4% and 19.5% were found among MSM who were new Canadians and for established Canadians respectively.¹³ Another study from the same cohort found that MSM under 30 years of age had a slightly higher incidence rate, of 0.72 per 100 PY, compared with 0.52 per 100 PY for MSM aged 30 years and older.¹⁴
• In Vancouver, the Vanguard study observes young MSM (under 30 years of age) for HIV infection and risk behaviours. In a recently published study, the incidence of HIV reported in the cohort was 1.9 per 100 PY.¹⁵
• The Enhanced Surveillance of Canadian Street Youth (ESCSY) is a national, multicentre, cross-sectional surveillance system of street youth aged 15 to 24 years in Canada. Of the youth tested in 2001, 1.0% were positive for HIV, 3.6% for hepatitis C virus, 11.5% for chlamydia and 14.2% for herpes simplex virus 2.¹⁶

Risk Behaviour Data among Youth

Research shows that Canadian youth begin to have sexual intercourse at a relatively early age:

• In the 1996 National Population Health Survey (NPHS), 25.6% of female participants in the 15 to 19 age group reported that they had had intercourse by the age of 15 years. Almost 20% of young men in this age group also reported that they had started having intercourse by this age.¹⁷

A substantial proportion of young people report having had multiple sexual partners in the past year:

• Among sexually experienced, single respondents (those never married and those divorced or widowed) in the 1996 NPHS, 29.4% of males aged 15 to 19 years had had more than one sex partner in the previous 12 months, and 27.5% of males aged 20 to 24 years had had more than one sex partner in this period. In comparison, 21.8% of females aged 15 to 19 years had had more than one sex partner in the previous 12 months, and the same percentage of females (21.9%) aged 20 to 24 years had had more than one sex partner in this time frame.¹⁷
• In a study of young gay and bisexual men aged 15 to 30 in Vancouver, 16% of the study subjects reported selling sex for money or drugs. HIV prevalence among those who had engaged in prostitution was significantly higher than those who had not (7.3% versus 1.1%), and incidence was higher as well (4.7 per 100 PY versus 0.9 per 100 PY).¹⁸

Research suggests that many Canadian youth are having unprotected sexual intercourse. Not using condoms appears to be more common among young women than it is among young men:

• Among sexually active youth aged 15 to 19 years in the 1994 NPHS (excluding subjects who had a single sex partner and who were married, common-law, divorced, or widowed), 51% of females and 29% of males reported never or only sometimes using a condom in the previous year.19 The corresponding percentages among those aged 20 to 24 years were 53% and 44%.¹⁹
• In an ongoing study of Montreal street youth, only 13.2% of participants reported always using condoms during vaginal intercourse, and only 32.4% reported always using condoms during anal intercourse.²⁰ Further risk behaviour data also indicate some alarming sexual risk behaviours: 33% had engaged in survival sex (prostitution), 51.1% had had sex with an IDU, 26.6% with an MSM, 40.6% with a prostitute and 8.2% with someone who was HIV positive.²¹

The extent of unprotected intercourse among youth is further captured in rates of chlamydia and gonorrhea among those aged 15 to 24 years:

• Figure 1 shows that in 2000, the reported incidence of chlamydia in Canada was highest among females aged 15 to 19 years (1,236.1/100,000 women). The reported incidence of gonorrhea in Canada was also highest in this group of young women (96.4/100,000) ^22,23 (Figure 2).

Figure 1. Reported genital chlamydia rates in Canada by age group and sex, 2000

Figure 2. Reported gonnorhea rates in Canada by age group and sex, 2000

Research reveals that levels of injecting drug use and injecting risk behaviours among youth, particularly those who are street-involved, require ongoing assessment:

• In a study of IDU in Calgary in 1998, 46% of participants who were under age 25 years as compared with 24% of those aged 25 or older reported that they had borrowed injection equipment in the previous six months.²⁴
• Recent results from the ongoing Montreal Street Youth Cohort Study showed that 42.8% of participants had a history of injecting drug use.²⁵ Also alarming was the incidence of the initiation of injecting drug use in street youth, estimated to be 7.9 per 100 person-years.²⁶
• In 2001, 18.3% of youth recruited for the Enhanced Surveillance of Canadian Street Youth reported that they had injected drugs in their lifetime.¹⁶

Comment

HIV/AIDS is affecting many subgroups of the Canadian population, including youth. Although the limited data available suggest that HIV prevalence is currently low among youth, sexual risk behaviour and STI data clearly indicate that the potential for HIV remains significant among young Canadians. More incidence and prevalence information as well as trend data on HIV-related risk behaviours are needed in order to guide and evaluate prevention programs for young Canadians. Epidemiological and behavioural data for high-risk youth, such as street youth, are also needed to assess fully the risk of HIV transmission in Canada's youth population.

References

1. UNAIDS.
   Report on the global HIV/AIDS epidemic. Geneva, July 2002.
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   High rates of HIV positivity among young injection users. Can J Infect Dis 2001;12(Suppl B):65B(Abstract 340P).
4. Miller CL, Li K, Laliberte N et al.
   Higher prevalence and incidence of HIV and hepatitis C and associated risk factors among young Aboriginal injection drug users. Can J Infect Dis 2003;14(Suppl A):48A-49A (Abstract 224P).
5. Miller CL, Li K, Braitstein P et al.
   The future face of co-infection: prevalence and incidence of HIV and hepatitis C co-infection among young injection drug users. Can J Infect Dis 2003;14(Suppl A):46A-47A (Abstract 217).
6. Roy E, Haley N, Leclerc P et al.
   HIV incidence in the Montreal Street Youth Cohort (MSYC). Can J Infect Dis 2002;12(Suppl A):49A(Abstract 317).
7. Roy E, Hayley N, Boivin JF et al.
   Étude de cohort sur l'infection au VIH chez les jeunes de la rue de Montréal. Final report to Health Canada, March 1998.
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   Determinants of HIV-related high risk behaviours among young offenders: a window of opportunity. Can J Public Health 1997;88(1):14-7.
9. Alary M, Joly JR, Parent R et al.
   Sentinel hospital surveillance of HIV infection in Quebec. Can Med Assoc J 1994; 151(7):975-80.
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    The B.C. prenatal study: 1989-94. Final report to Health Canada, January 1995.
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    HIV infection in young Canadian adults before and after an international exchange program: 1986-96. 6th Conference of the International Society of Travel Medicine, Montreal, June 1999.
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14. Alary M, Remis RS, Otis J et al., the OMEGA Study Group.
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15. Weber AE, Craib KJ, Chan K et al.
    Determinants of HIV serconversion in an era of increasing HIV infection among young gay and bisexual men. AIDS 2003;17(5):774-7.
16. Health Canada.
    Enhanced surveillance of Canadian street youth. Sexual Health and STI Section, Community Acquired Infections Division, Centre for Infectious Disease Prevention and Control, Health Canada.
17. Maticka-Tyndale E, Barrett M, McKay A.
    Adolescent sexual and reproductive health in Canada: a review of national data sources and their limitations. Can J Hum Sex 2000;9(1):41-65.
18. Weber AE, Craib KJP, Chan K et al.
    Sex trade involvement and rates of human immunodeficiency virus positivity among young gay and bisexual men. Int J Epidemiol 2001;30(6):1449-54.
19. Galambos NL, Tilton-Weaver LC.
    Multiple-risk behaviour in adolescents and young adults. Health Rep 1998; 10(2):9-20.
20. Roy E, Haley N, Leclerc P et al.
    Prevalence of HIV infection and risk behaviours among Montreal street youth. Int J STD AIDS 2000; 11(4):241-47.
21. Roy E, Haley N, Leclerc P et al.
    HIV and HCV risk behaviours in the new Montreal Street Youth Cohort. Can J Infect Dis 2003;14(Suppl A):46A(Abstract 216).
22. Health Canada.
    STD data tables Appendix 1.1. Division of Sexual Health Promotion and STD Prevention and Control, CIDPC, Health Canada. .
23. Health Canada.
    STD data tables Appendix 2.2. Division of Sexual Health Promotion and STD Prevention and Control, CIDPC, Health Canada.
24. Guenter CD, Fonesca K, Nielsen DM et al.
    HIV Prevalence remains low among Calgary's needle exchange program participants. Can J Public Health 2000; 91(2);129-32.
25. Roy E, Haley N, Leclerc P et al.
    Heroin or cocaine? How can we predict which drug Montreal street youth will first inject? Can J Infect Dis 2003;14(Suppl A):49A (Abstract 226P).
26. Roy E, Haley N, Leclerc P et al.
    Drug use behaviours of new injectors in the Montreal street youth cohort. Can J Infect Dis 2000;11(Suppl B):54B (Abstract 301).

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