HIV Infections Among MSM In Canada

HIV/AIDS Epi Updates

April 2003

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HIV Infections Among MSM In Canada

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Introduction

In Canada, the HIV/AIDS epidemic has had a tremendous impact on men who have sex with men (MSM). Even though the toll of the epidemic no longer affects MSM to the same extent that it did in the early-to-mid 1980s, this group still accounts for the largest number of HIV and AIDS case reports. Recent data on HIV incidence and risk behaviours suggest that MSM continue to be at risk for HIV infection and other sexually transmitted diseases (STDs). This report updates the current information on the status of HIV and AIDS among MSM in Canada.

AIDS Surveillance Data

• As of June 30, 2002, the Centre for Infectious Disease Prevention and Control (CIDPC) reported a cumulative total of 18,336 AIDS cases. Of the 16,669 adult male AIDS cases, 77.6% were attributed to MSM and an additional 5.0% were attributed to the combined group MSM and injecting drug users (MSM/IDU).¹

• Figure 1 shows a steady decrease in the proportion of adult AIDS cases attributed to MSM reported to CIDPC from 1986-1999. In 2000, this proportion increased to 50.4% and has decreased to 46.4% in 2001 and to 40.3% in the first half of 2002. The annual number of AIDS cases attributed to MSM (unadjusted for reporting delay) peaked in 1992-1994, decreased sharply during 1995-97, began to level off in 1999-2000, and decreased again in 2001^1.

• The proportion of adult AIDS cases attributed to MSM who are also injecting drug users (MSM/IDU) has remained relatively steady, varying between 3.7 and 5.3% during the last 5 years.¹

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HIV Surveillance Data

While AIDS data provide information on HIV infection that occurred about 10 years in the past, HIV data provide a picture of more recent infections.

• Data from provincial HIV testing programs, collated and synthesized at the national level by CIDPC, shows that prior to 1996, 77.1% of positive HIV test reports among adult males were attributed to MSM. (Figure 2) This proportion decreased steadily to level off at around 48.5% during 1997-1999. It increased to 53.6% in 2000 and then decreased to 48.3% in 2001. In the first half of 2002, this percentage was 51.4%.¹

• A similar trend is observed in the absolute number of positive HIV test reports among adult males attributed to MSM: a steady decline to 421 reports in 1999, an increase to 467 in 2000, and a decrease to 402 cases reported in 2001. The year 2000 was the first time an increase has been seen among MSM test reports in the HIV surveillance data since the 1980s.¹

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High rates of new HIV infections in some parts of Canada

• Data from Ontario show a recent increase in the rate of new HIV infections among MSM who are repeat testers for HIV, from 0.79 infections per 100 person-years in 1996 to 1.39 in 1999. Incidence was significantly higher in Toronto and Ottawa compared to the rest of Ontario.² In both centers, incidence rates increased in 1996-1999 (Toronto: relative risk = 1.11 per year; p=0.006, Ottawa: relative risk = 1.49 per year; p=0.02).² In 2000, incidence appears to have stabilized in Ontario.² Using a new laboratory technique to identify recent infections among those newly diagnosed for HIV (STARHS assay) during 1999-2001, HIV incidence appeared to decrease among MSM in Toronto over the 22-month study period, from 4.3 in 1999 to 2.8 in 2001. In contrast, HIV incidence among MSM in Ottawa appeared to increase, from less than 0.1 in 1999 to 0.86 in first half of 2001.³

• In Quebec, the Omega Cohort provides information on the incidence and psychosocial determinants of HIV infection among MSM living in Montreal. From October 1996 to August 2001, overall HIV incidence remained relatively stable, varying from 0.44 to 0.71 per 100 PY without any clear increasing or decreasing trend. However, trends in HIV incidence varied by age. The relative rates in 2001 over 2000 were 2.7 for younger MSM and 1.3 for older MSM.⁴ From October 1996 to August 2001, the incidence was 0.57 per 100 PY.⁵

• In British Columbia, results from the Vanguard study, a prospective cohort of young gay and bisexual men in Vancouver, show that the annual rate of new HIV infections among these men who had never injected drugs increased from a range of 0.2-1.0 per 100 PY during the years 1996-99 to 2.0 per 100 PY in 2000 and to 2.5 per 100 PY in the first nine months of 2001.⁶

• With respect to HIV prevalence, data (self-reported or tested) from surveys done directly among MSM showed a very high rate before 1990: 23-32% in Vancouver;^7-8 27-57% in Toronto;^7,9 20-25% in Montreal;^7,10 and between 10-20% in other regions of Canada.⁷ By 1998/2000, it appeared that there was some decline in HIV prevalence rate among MSM surveyed by similar methods (e.g. 16% in Vancouver,^11-12 10-16% in Montreal).^13-15 However, a high prevalence rate is still seen among MSM who are also injection drug users, for example, 23-28% among MSM/IDU attending needle exchange programs in Ontario (1991-94)¹⁶ and 14-22% among those in Quebec (1995-2000).^17-18

• In the Omega Cohort, results found that HIV prevalence increased with age from a rate of 0.0% in MSM under 20 years, to 3.1% in those aged 40-44 years, and then decreased to 0.4% among those 45 years of age or over. However, this trend was not statistically different.⁴

Continuing Risk Behavior Among MSM

Recent data on risk behaviours suggest that MSM continue to be at considerable risk for HIV infection and other STDs by engaging in receptive or insertive unprotected anal intercourse (UAI) with casual or regular partners, or practicing unsafe sex (oral or anal) with a known HIV positive partner:

• It is estimated that around 15% of Montreal?s MSM are currently HIV infected. Results from the Montreal Omega Cohort Study indicate that 12% of MSM practice UAI with casual partners. This could result in a significant increase in the risk of new HIV infections.¹⁹ From 1997 to 2001, an increasing trend in UAI is seen among casual partners (8.2-12.8%, p=0.007).²⁰

• In another survey in Montreal, the prevalence of reported UAI was 12% among MSM recruited in bars or saunas, but was up to 21-24% among MSM who were HIV-positive.^13-14 About 4% of the 500 surveyed men reported having consensual unprotected anal sex with a HIV-positive male partner.¹⁴

• With respect to relapse to risky behaviors, available data indicate that 10% of the Montreal cohort and 26-30% of the Vancouver cohort who reported safe sex at baseline, disclosed relapse to unprotected anal sex at follow-up six to twelve months later.^21-22

• Between May 1995 and September 2001, men aged 15 to 35 years enrolled in a cohort study of MSM in the Greater Vancouver region reported increasing unprotected insertive (relative risk:3.5) and receptive (relative risk:5.1) anal sex with an HIV positive partner in association with seroconversion.²³

• Data from the Vancouver cohort and the Montreal cohort were combined and analyzed, comparing the sexual behaviours for HIV-positive and HIV-negative gay and bisexual men, aged 16-30 years. Results show that 56% of HIV-positive men and 40% of HIV-negative men reported having engaged in receptive UAI during the previous 6 months or year.²⁴ More recently, high-risk behaviour among MSM in both cities was associated with nitrite inhalant use and sex in public and commercial sex venues. Independent determinants of risk-taking for men in both cities were the use of poppers (Vancourver: odds ratio:2.1, Montreal: OR:2.9) and having sex in a bathhouse (Vancouver: OR:1.9, Montreal OR: 1.8). In Vancouver, having sex in a bar (OR:1.8) and having at least 20 casual partners in the previous year (OR:1.7) were associated with high-risk sex. For men in Montreal, having a casual partner (OR:3.0) and having at least two regular partners in the previous year (OR:3.0) were independently associated with high-risk sexual behaviour.²⁵

• STD data may be used as a marker for unsafe sexual behavior. Preliminary data for 1999-2000 show increased reports of rectal gonorrhea among adult males in Toronto and Ottawa compared to earlier years, and a potential outbreak of syphilis among MSM in Calgary.²⁶ These data suggest increases in unprotected sexual encounters among MSM.

Comment

A number of biases must be taken into account when interpreting the results noted above. HIV diagnostic data are limited to persons who present themselves for testing and so trends in these numbers may be influenced by testing patterns or improved ability to remove duplicate tests. In addition, identifying information that accompanies HIV testing data is sometimes incomplete or inaccurate, and this may limit the usefulness of HIV incidence estimates derived from repeat-tester data. Results of cohort studies are limited by selection biases, loss to follow-up, and problems with generalizability.

Despite these limitations, available data suggest that there was an increase in HIV infections among MSM in some centres in 1999-2000 compared to immediately preceding years. Meanwhile, high-risk behaviours are still present nationally among MSM.

Similar data indicating increases of high-risk behaviour among MSM, and a potential for an increase of HIV incidence, have been noted elsewhere. For example, increases have been seen for HIV-associated risk behaviours and/or STDs among MSM in the USA,^27-29 Amsterdam,³⁰ and Sydney, Australia.³¹

Several hypotheses might explain these increases in HIV associated risk behaviours, including: feelings of complacency or optimism related to the success of antiretroviral therapy,²⁶ false reassurance upon learning an HIV-negative result, a lack of direct experience of the AIDS epidemic among the younger generation of gay men, a desire to escape the rigorous norms and standards required for a lifetime of safe sex,^{2, 32-33} alcohol/drug use^25,34-36 and the impact of internet chat rooms as a risk environment.³⁷

Taken together, the recent findings indicate that HIV infections increased among MSM in some parts of Canada during 1999-2000. There is a clear need for innovative prevention programs to reduce the spread of HIV and also STD among the gay community. National risk behaviour measures over time would be useful to better characterize the epidemic among MSM and to support effective prevention programs. If antiretroviral therapy becomes less effective because of the viral resistance, the actual level of risk behaviour could significantly increase the incidence of HIV.

References

1. Health Canada. HIV and AIDS in Canada: Surveillance Report to June 30, 2002. Division of HIV/AIDS Epidemiology and Surveillance, Centre for Infectious Disease Prevention and Control, Health Canada, November 2002.

2. Calzavara L, Burchell A, Major C, Remis R, Corey P, Myers T, Millson P, Wallace E, and the Polaris Study Team. Increases HIV incidence among men who have sex with men undergoing repeat diagonostic HIV testing in Ontario, Canada. AIDS 2002, 16:1655-1661.

3. Remis RS; Major C; Swantee C; Fearon M; Wallace E; Whittingham E Trends in HIV incidence in Ontario based on the STARHS d assay: Uupdate to July 2001. Can J Infect Dis, 2002; Vol 13 (Suppl A): 66A, 372.

4. Remis RS, Alary M, Otis J, Demers E, Masse B, Vincelette J, Turmel B, Lavoie R, LeClerc R, Parent R, and the OMEGA Study Group. Trends in HIV infection in the omega cohort of men who have sex with men (MSM) in Montreal,1996-2001. Canadian Journal of Infectious Diseases 2002, 13 [Supplement A], 50A (Abstract 320).

5. Alary M, Remis RS, Otis J, Masse B, Turmel B, LeClerc R, Lavoie R, Vincelette J, Parent R, and the OMEGA Study Group. Risk factors for HIV seroconversion among men having sex with men (MSM) in Montreal. Canadian Journal of Infectious Diseases 2002, 13 [Supplement A], 50A ,307.

6. Martindale SL, Cook D, Weber AE, Miller ML, Chan K, Craib KJP, Hogg RS. The impact of STARHS "Detuned Assay" results on HIV incidence calculations in an ongoing cohort of men who have sex with men (MSM) in Vancouver. Can J Infect Dis 2002; 13(Supplement A): 65A (Abstract 369P).

7. Myers T, Godin G, Calzavara L, Lambert J, Locker D and the Canadian AIDS Society Team. The Canadian Survey of Gay and Bisexual Men and HIV Infection: Men?s Survey. The National AIDS Clearing House, Ottawa, Ontario (Catalogue ISBN 0-921906-14-5).

8. Craib KJP, Strathdee SA, Hogg RS, Cornelisse PGA, Willoughby BC, Schechter MT et al. Incidence Rates of HIV-1Infection, AIDS Progression and Mortality in the Vancouver Lymphadenopathy-AIDS Study: Results at 14 years {Abstract 213}. Can J Inf Dis 1998;9:31A.

9. Coates R, Calzavara LM, Read SE, Fanning MM, Shepherd F, Mac Fadden DK et al. A Prospective Study of Male Sexual Contacts of Individuals With ARC or AIDS. Final report to National Health Research and Development Program, 1992.

10. Remis RS, Najjar M, Pass C, Paradis G. Seroepidemiological Study of HIV Infection And Sexual Behaviour Among Men Attending a Medical Clinic in Montreal {Abstract W.A.P.42}. Vth Int Conf on AIDS, Montreal, Canada, June 1989.

11. Low-Beer S, Bartholomew K, Weber AE, Chan K, Landolt M, Oram D, Schilder A, Hogg R. A demographic and health profile of gay and bisexual men in a large Canadian urban setting. AIDS Care 2002; 14 (1):111-115.

12. Lou-Beer S, Weber AE, Bartholomew K, Landolt M, Oram D, Schilder A, O?Shaughnessy MV, Hogg RS. A Demographic And Health Profile of HIV-Positive Gay and Bisexual Men in The West End of Vancouver. Can J Infect Dis 1999;10:62B.

13. Dumas J, Lavoie R, Desjardins Y. Project national Three Cities, Volet Montréalais: Etudes de besoins en matière de santé des hommes gais de Montréal. Action Séro Zéro. Report to the HIV/AIDS Policy, Coordination and Program Division, Health Canada, July 2000; presentation by Lavoie R. in Proceedings of the MSM/IDU Consultation Meeting (March 8-9, 2001, Ottawa, Canada). Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, Health Canada.

14. Lavoie R, Desjardins Y, Otis J. Sex et Réalités: Les nouvelles thérapies pour le VIH/sida et les comportements sexuels sécuritaires des hommes ayant des relations sexuelles avec d?autres hommes. Action Séro Zéro. Report to the HIV/AIDS Policy, Coordination and Program Division, Health Canada, July 2000.

15. Low-Beer S, Bartholomew K, Weber AE, Chan K, Landolt M, Oram D, Schilder AJ, and Hogg RS. A demogramphic and health profile of gay and bisexual men in a large Canadian urban setting, AIDS Care 2002, 14{1}, 111-115.

16. Millson PE, Myers T, Rankin J, Major C, Fearon M, Rugby J. Double Jeopardy: HIV infection risk in male drug injectors who also have sex with men {Abstract 324}. Can J Infect Dis 1995;6:41B.

17. Poulin C, Alary M, Noel L, Classens C, Lachance C. Prevalence and Incidence of HIV Among Injecting Drug Users (IDU) Attending a Needle Exchange Program NEP in Quebec City {Abstract 218}. Can J Inf Dis 1997; 8 Suppl A:27.

18. Hankins C, Alary M, Parent R, Blanchette C, Claessens and the SurvUDI Working Group. Knowledge of HIV status among MSM and heterosexual men who inject drugs. Paper presented at the 10th Annual Canadian Conference on HIV/AIDS Research (May 2001, Toronto) and personal communication (Hankins C, April 2001).

19. Dufour A, Alary M, Otis J, Remis RS, Masse B, Turmel B, Vincelette J, Parent R, Lavoie R, LeClerc R and the Omega Study Group. Risk behaviours and HIV infection among men having sexual relations with men: Baseline characteristics of participants in the Omega Cohort Study, Quebec, Canada.. Can J Public Health 2000; (91) 5:345-349.

20. George C, Alary M, Otis J, Demers E, Remis RS, Turmel B, LeClerc R, Lavoie R, Vincelette J, Parent R, Masse B, and the OMEGA Study Group. Increase in unprotected anal intercourse (UAI) among men having sexual relations with other men (MSM) participating in the Omega Cohort Study. Has this North American wave finally reached Montreal? Canadian Journal of Infectious Diseases 2002, 13[Suppl.A], 45A, 306.

21. Remis RS, Alary M, Otis J. HIV infection and risk behaviours in young gay and bisexual men [Letter to Editor]. CMAJ 2000;163(1):14-15; and Response to this Letter by Hogg RS, Strathdee SA, Chan K, Martindale SL, Craib KJP.

22. Strathdee SA, Martindale SL, Cornelisse PGA, Miller ML, Craib KJP, Schechter MT, O?Shaughnessy M, Hogg RS. HIV infection and risk behaviours among young gay and bisexual men in Vancouver. CMAJ 2000;162(1):21-25 and personal communication (Hogg B, April 2001).

23. Weber AE, Craib KJP, Chan K, Marindale SL, Miller ML, cook K, Schechter MT, and Hogg RS. Predictors of HIV sero conversion among young men who have sex with men. Can J Infect Dis, 2002; Vol 13 (Suppl A): 49A, 319.

24. Weber, AE Risk Factors associated with HIV Infection among young gay and bisexual men in Canada. JAIDS 2001; (28)1:81-88.

25. Weber AE, Otis J, Chan K, Lavoie R, Martindale SL, LeClerc R, Miller ML, Turmel B, Craib KJP, Alary M, Schechter MT, And Hogg RS. Factors associated with high-risk sexual behaviour among men who have sex with men (MSM) in two Canadian cohorts. Canadian Journal of Infectious Diseases 2002, 13[Suppl.A], 45A, 355.

26. Presentation by A. Singh in Proceedings of the MSM/IDU Consultation Meeting (March 8-9, 2001, Ottawa, Canada). Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, Health Canada.

27. Denning P, Nakashima AK, Wortley P. Increasing rates of unprotected anal intercourse among HIV-infected men who have sex with men in the Unites States. 13^th International AIDS Conference, July 9-14, 2000, Durban, South Africa (Abstract no. ThOrC714).

28. Page-Shafer KA, McFarland W, Kohn R, Klausner J, et al. Increases in unsafe sex and rectal gonorrhea among men who have sex with men - San Francisco, California, 1994-97. MMWR 1999;48:45-8.

29. Handsfield HH, Whittington WLH, Desmon S, Celum C, Krekeler B. Resurgent bacterial sexually transmitted disease among men who have sex with men - King County, Washington, 1997-99. MMWR 1999;48:773-7.

30. Dukers N, de Wit J, Goudsmit J, Coutinho R. Recent increase in sexual risk behaviour and sexually transmitted diseases in a cohort of homosexual men: the price of highly active antiretroviral therapy? 13^th International AIDS Conference on AIDS, Durban, South Africa, July 9-14, 2000 {Abstract ThOrC715}.

31. Van De Ven P, Prestage G, French J, Knox S, Kippax S. Increase in unprotected anal intercourse with casual partners among Sydney gay men in 1996-98. Aust N Z Public Health 1998;22:814-8.

32. Ostrow DG, Fox K, Chmiel JS. Attitudes toward highly active antiretroviral therapy predict sexual risk-taking among HIV infected and uninfected gay men in the Multicenter AIDS Cohort Study (MACS). 13^th International AIDS Conference on AIDS, Durban, South Africa, July 9-14, 2000 {Abstract ThOrC719}.

33. Katz MH. AIDS epidemic in San Francisco among men who report sex with men: successes and challenges of HIV prevention. J Acquir Immune Defic Syndr 1997;14(Suppl 2):838-46.

34. Dufour A, Alary M, Otis J, Noel R, Remis RS, Masse B, Parent R, Turmel B, Lavoie R, LeClerc R, Vincelette and the Omega Study Group. Correlates of Risky Behaviours Among Young and Older Men Having Sexual Relations With Men in Montréal, Québec, Canada. JAIDS 2000;23:272-8.

35. Mansergh G, Colfax GN, Marks G, Rader M, Guzman R, Buchbinder S. The Circuit Party Men?s Health Survey: Findings and Implications for Gay and Bisexual Men. American Journal of Public Health 2001; 91:953-8.

36. Dolezal C, Meyer-Bahlburg HF, Remien RH and Petkova E. Substance Use During Sex and Sensation Seeking as Predictors of Sexual Risk Behaviour Among HIV+ and HIV- Gay Men. AIDS and Behavior1997; 1:19-28.

37. McFarlane M, Bull S, Reitmeijer S. The Internet as a newly emerging risk environment for sexually transmitted disease. JAMA 2000;284(4):443-6.

For more information please contact:

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Health Canada

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