No increase in HIV incidence observed in a cohort of men who have sex with other men in Montreal

Evolving the gay, bisexual and other men who have sex with men time-based deferral to sexual risk screening for all donors: The contribution of Canadian research programmes

BACKGROUND AND OBJECTIVES

In Canada, the time deferral for gay, bisexual and other men who have sex with men (gbMSM) to donate blood has gradually decreased. In September 2022, this deferral was replaced with sexual behaviour-based screening for all donors. We investigate how data from targeted research programmes addressed knowledge gaps to support this change.

MATERIALS AND METHODS

We conducted a scoping review describing the Canadian literature available before the research programmes relating to (1) behavioural indicators of HIV risk and (2) attitudes to blood donation among gbMSM, current donors and the general population. We summarize the targeted research programmes, their outputs and impact to date.

RESULTS

For question 1, five projects met inclusion criteria. For question 2, three articles met inclusion criteria. Knowledge gaps identified were insufficient evidence of HIV incidence in gbMSM who met other donor eligibility criteria and scant data on opinions and views of blood donation and screening criteria for sexual risk behaviours. The research programmes funded 19 projects at 11 different research sites involving over 100 individual researchers/collaborators resulting in 19 peer-reviewed publications to date. Leveraging existing gbMSM cohorts yielded relevant HIV incidence data to inform safety modelling studies. Findings indicated that sexual behaviour-based screening was acceptable to gbMSM and donors, and donor discomfort around specific questions could be mitigated with clear explanations.

CONCLUSION

Targeted research programmes filled critical knowledge gaps and informed a change to gender-neutral, sexual behaviour-based screening for all donors. Findings supported successful implementation of these changes with research-informed staff training.

Running in place: implications of HIV incidence estimates among urban men who have sex with men in the United States and other industrialized countries

Attempts to document changing HIV incidence rates among MSM are compromised by issues of generalizability and statistical power. To address these issues, this paper reports annualized mean HIV incidence rates from the entire published incidence literature on MSM from Europe, North America and Australia for the period 1995-2005. Publications that met the entry criteria were coded for region of the world, sampling method and year of study. From these reports, we calculated a mean incidence rate with confidence intervals for these variables. Although no differences in mean incidence rates were found for MSM from 1995 to 2005, HIV incidence rates are lower in Australia than either North America or Europe. We calculated a mean incidence rate of 2.39% for MSM in the United States, which if sustained within a cohort of MSM, would yield HIV prevalence rate of approximately 40% at age 40. These extrapolations overlap published HIV prevalence rates for MSM younger than age 40 in the United States. HIV incidence rates in the 2-3% range will adversely affect the health of gay male communities for decades to come. This analysis suggests that greater attention should be devoted to the question of how best to design prevention interventions that will lower HIV incidence rates among gay men.

Testing bias in calculating HIV incidence from the Serologic Testing Algorithm for Recent HIV Seroconversion

OBJECTIVE

Incidence is critical in monitoring HIV infection in populations but often difficult to measure. The Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS) can estimate HIV incidence from a single specimen at low cost. Nevertheless, HIV testing patterns may introduce bias, rendering interpretation of the STARHS result problematic. We found empirical evidence of such bias in Ontario using the STARHS formula with varied window periods

METHODS

In a hypothetical population of homosexual men, we calculated HIV incidence from the STARHS assay on the basis of incidence density, study duration, STARHS window period and intertest interval. We also incorporated the increased likelihood of a newly infected person having an HIV test due to seroconversion illness or high-risk behaviours ('seroconversion effect' or SCE). We also varied the intertest interval inversely as a function of incidence density. To adjust incidence estimates for bias, we fit empirical STARHS data to an algebraic formula expressing measured HIV incidence as a function of SCE and incidence.

RESULTS

Incidence density estimates were unbiased when SCE or incidence density-interval interactions were absent. However, estimated incidence density was higher than true incidence density in the presence of SCE, as much as seven-fold higher under certain conditions. The goodness-of-fit provided estimates with an excellent fit, yielding plausible results.

CONCLUSION

HIV incidence from STARHS may be strongly biased because of early testing in recently infected persons, resulting in substantial overestimation, at least amongst men who have sex with men. Thus, incidence estimates from STARHS must be interpreted with considerable caution. Nevertheless, incidence estimates may be adjusted to yield unbiased results.

Determinants of HIV seroconversion among men who have sex with men living in a low HIV incidence population in the era of highly active antiretroviral therapies

OBJECTIVE

To estimate human immunodeficiency virus (HIV) incidence and associated risk factors among men who have sex with men (MSM) participating in the Omega Cohort Study in Montreal, 1996-2003.

METHODS

Longitudinal study of 1587 MSM seronegative at baseline with > or =1 six-month follow-up visit. Multivariate Cox regression with time-dependent variables was used for data analysis.

RESULTS

HIV incidence was 0.62 per 100 person-years (95% confidence interval: 0.41-0.84). In multivariate analyses compared with subjects not reporting any anal sex with serodiscordant or casual partners, those reporting anal sex with such partners (all P values <0.05), whether consistently protected [hazard ratio (HR) = 3.4], or unprotected exclusively receptive (HR = 12.0), exclusively insertive (HR = 4.7), or both receptive and insertive (HR = 8.3), were at increased risk of seroconversion. Sexual behaviors with seroconcordant regular partners were not associated with seroconversion.

CONCLUSION

These results observed in a cohort of MSM with low HIV incidence provide new insights regarding the debate about harm-reduction strategies to prevent sexual HIV transmission.

Trends in HIV incidence in homosexual men in developed countries

Objectives: To describe trends in HIV notifications and in other measures of HIV incidence in homosexual men in developed countries. Methods: A literature search was conducted using PubMed. In addition to the peer-reviewed literature, data on HIV surveillance trends were sought by searching websites of surveillance authorities in developed countries. Results: The availability of long-term HIV surveillance data varied considerably. However, in almost all jurisdictions in which such data were available, notifications of new HIV diagnoses among homosexual men have increased, mostly since the late 1990s. The magnitude of this increase varied, but was more than 50% in many countries. There were much fewer data available on trends in direct measures of HIV incidence in homosexual men, and increases in HIV testing rates may have contributed to the increases in HIV diagnoses in many countries. However, since the late 1990s, several clinic- and community-based cohort studies in Europe and North America reported increasing incidence. Conclusion: There were increases in HIV notifications in homosexual men in almost all developed countries, starting in the late 1990s and continuing to 2006. Although increases in HIV testing probably contributed to the increases in some settings, limited cohort data do support the existence of a true increase in HIV incidence in European and North American countries. Improved monitoring of HIV incidence in homosexual men at the population level is required to allow more timely assessment of the drivers underlying such trends.

Number of risk acts by relationship status and partner serostatus: Findings from the HIM cohort of homosexually active men in Sydney, Australia

In recent years, increases in both risk behavior and in seroconversion among homosexually active men have been noted in a number of parts of the world. Data were available from 903 HIV negative homosexual men regarding number of acts of unprotected anal intercourse (UAI), separated into receptive and insertive UAI, with and without ejaculation, with steady and with casual partners. Partners were classified according to serostatus as reported by respondents. Men (N = 325) reported 13,692 UAI acts, most of which were with steady partners, of whom most were reported to be HIV-negative. With HIV-positive partners, both steady and casual, and with casual partners of unknown serostatus, receptive UAI with ejaculation was relatively rare. Insertive UAI without ejaculation was relatively common with casual partners of unknown serostatus. Patterns of UAI suggest that risk of transmission may be greater with steady partners. Men appear to modify practice according to both the nature of the relationship (steady or casual) and (assumed) serostatus of partner.

Men who have sex with men (MSM) in public sex environments (Pses): a systematic review of quantitative literature

We systematically review quantitative research relating to the sexual behaviours of MSM in PSEs. We examine the methodological rigour of these studies to determine an appropriate framework for future PSE-based research and quantify sexual behavioural trends therein. Medline, BIDS, Web of Science and recent HIV/AIDS conferences were searched according to a systematic inclusion criteria. Nine papers were included for review. Recruitment of participants' outwith PSE settings, and low response rates (6%) of participants contacted in situ, question the validity and generalizability of current evidence. Most PSE users were gay or bisexually identified and half of men in the gay community reported recent PSE use. Around 10% of men reported casual status-unknown/serodiscordant unprotected anal intercourse (UAI) within PSEs. HIV testing rates amongst PSE users were similar to the wider gay community, though the proportion of men who tested positive was twice as high. Rates of casual UAI suggest that PSEs represent important sites for HIV prevention. However, since extant evidence is scant and methodologically flawed, further research is urgent. Such work must recruit participants in situ, and obtain satisfactory response rates, to be generalizable to the wider population of men who cruise.

Lack of evidence of sexual transmission of hepatitis C virus in a prospective cohort study of men who have sex with men

OBJECTIVES

We studied the prevalence and incidence of hepatitis C virus (HCV) infection in the ongoing Omega Cohort Study of men who have sex with men (MSM).

METHODS

From January to September 2001, consenting men (n = 1085) attending a follow-up visit to the ongoing Omega Cohort Study were tested for HCV. If the test results were positive for HCV, we compared them with test results from previous serum samples collected from the time of entry into the original cohort study to determine the time of infection.

RESULTS

HCV prevalence at entry was 2.9% and was strongly associated with injection drug use (32.9% vs 0.3%, P<.0001). Only 1 seroconversion was identified in 2653 person-years of follow-up (incidence rate = 0.038 per 100 person-years). The seroconverter was an active injection drug user who reported needle sharing.

CONCLUSIONS

Sexual transmission of HCV among MSM appears to be rare.

Factors associated with a decrease in the prevalence of drug resistance in newly HIV-1 infected individuals in Montreal

OBJECTIVE

A decrease in the prevalence of drug resistance (DR) has been observed among recently infected (RI) individuals in Montreal. A study of chronically infected (CI) patients, who represent potential HIV-1 transmitters, was carried out in order to ascertain biological factors associated with this trend change.

DESIGN AND METHODS

Retrospective analysis of CI patients was performed for the period 1996-2003. Changes in mean viral load and DR prevalence were assessed in CI patients (n = 2328) and compared to those in RI patients (n = 180) living in the same geographic area.

RESULTS

A decrease was observed in the prevalence of DR among RI patients, from 13.0% in 1997-2000 to 4.0% in 2001-2003 (P = 0.04). From 1996 to 2000, the mean viral load in the CI patients decreased by 1.34 log10, to remain steady thereafter. The proportion of CI patients who interrupt treatment increased steadily over 1997-2003 from 3.1% to 16.5% (P < 0.0001). Since 1999, when genotyping analysis became available, we have observed a 0.9 log10 decrease in mean viral load among 602 genotyped CI patients harbouring any major mutations.

CONCLUSION

The decrease in transmission of DR documented in Montreal since 2000 coincides with the drop in mean viral load observed in CI patients. Factors that contribute to the decrease in viral load include routine access to genotyping and availability of more potent antiretroviral drugs. Plasma viral load seems to represent the main predictor for the transmission of DR.

HIV incidence among street youth in Montreal, Canada

OBJECTIVES

To estimate HIV incidence and identify predictors of seroconversion among Montreal street youth.

METHODS

From 1995 to 2000, street youth aged 14-25 years were recruited in a prospective cohort study. Interviews were conducted semiannually and included anti-HIV antibody testing. Among subjects who tested HIV negative at study entry and were interviewed at least twice, predictors of HIV seroconversion were identified using Cox regression. Variables considered as potential predictors were age, sex, injection drug use, being a male reporting male sexual partners, and survival sex.

RESULTS

Overall, 1013 youth were recruited in the study. HIV prevalence at study entry was 1.4% [95% confidence interval (CI) 0.8-2.4] and was stable over the 6 recruitment years. Among the 863 subjects selected for the incidence analysis, 66.7% were boys, 47.2% had ever injected drugs at study entry, and 25.7% had ever engaged in survival sex. The selected participants cumulated 2327 person-years of follow-up and 16 HIV seroconversions were observed, for an incidence rate of 0.69 per 100 person-years (95% CI 0.39-1.11). In univariate analysis, injection drug use [hazard ratio (HR), 7.0] and involvement in survival sex (HR, 4.0) were associated with HIV incidence. In the multivariate analysis, only injection drug use was retained.

CONCLUSIONS

Among Montreal street youth, injection drug use was the strongest predictor of HIV seroconversion. Prevention of initiation into injection drug use must become a public health priority.