HPV genotyping and risk factors for anal high-risk HPV infection in men who have sex with men from Toronto, Canada

Men who have sex with men (MSM) are disproportionately affected by anal cancer, predominantly caused by high-risk (HR) human papillomavirus (HPV) infection. Currently, the nonavalent HPV vaccine provides coverage against nine HPV genotypes, including seven HR-HPV genotypes. Here, we characterize anal HR-HPV genotype distribution and associated risk factors in MSM from Toronto, Canada recruited between September 2010 and June 2012. Wilcoxon-Mann-Whitney test was used for continuous variables, Chi-square test was performed for categorical variables, and a multivariable model using logistic regression was created to assess for correlates of anal HR-HPV infection. A total of 442 MSM were recruited, with a median age of 45 (IQR 38-50) and an overall HPV prevalence of 82%. The prevalence of any HR-HPV infection was 65.3% and 50.7% in the HIV-positive and HIV-negative MSM, respectively. No participant tested positive for all genotypes covered by the nonavalent vaccine. HIV status (aOR 1.806; 95% CI 1.159-2.816), smoking (aOR 2.176; 95% CI 1.285-3.685) and the number of lifetime sexual partners (aOR 2.466; 95% CI 1.092-5.567) were independent risk factors for anal HR-HPV infection. Our findings will be useful to inform HPV vaccine rollout and HPV prevention strategies in Canadian MSM.

Prevalence of Sexually Transmitted Viral and Bacterial Infections in HIV-Positive and HIV-Negative Men Who Have Sex with Men in Toronto

Background

Hepatitis B (HBV), hepatitis C (HCV) and other sexually transmitted infections (STIs) have been associated with HIV transmission risk and disease progression among gay men and other men who have sex with men (MSM), but the frequency and distribution of STIs in this community in Canada has not been extensively studied.

Methods

We recruited MSM living with and without HIV from a large primary care clinic in Toronto. Participants completed a detailed socio-behavioural questionnaire using ACASI and provided blood for syphilis, HIV, HBV and HCV, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), and human cytomegalovirus (CMV) serology, urine for chlamydia and gonorrhea, and a self-collected anal swab for human papillomavirus (HPV) molecular diagnostics. Prevalences were expressed as a proportion and compared using chi-square.

Results

442 MSM were recruited, 294 living with HIV and 148 without. Active syphilis (11.0% vs. 3.4%), ever HBV (49.4% vs. 19.1%), HCV (10.4% vs. 3.4%), HSV-2 (55.9% vs. 38.2%), CMV (98.3% vs. 80.3%) and high-risk (HR) anal HPV (67.6% vs. 51.7%) infections were significantly more common in men living with HIV. Chlamydia and gonorrhea were infrequent in both groups. Regardless of HIV infection status, age and number of lifetime male sexual partners were associated with HBV infection and lifetime injection drug use with HCV infection.

Conclusions

Syphilis and viral infections, including HBV, HCV, HSV-2, CMV, and HR-HPV, were common in this clinic-based population of MSM in Toronto and more frequent among MSM living with HIV. This argues for the implementation of routine screening, vaccine-based prevention, and education programs in this high-risk population.

Symptomatic primary HIV infection or risk experiences? Circumstances surrounding HIV testing and diagnosis among recent seroconverters

Our objective was to understand the circumstances surrounding HIV testing among recent HIV seroconverters ( n = 80) compared to HIV-negative controls ( n = 106) in Ontario, Canada using self-reported interview data. Diagnosis of symptomatic primary HIV infection (SPHI) was defined as diagnosis by the participant's physician. Testing in response to symptoms was reported by 42% of seroconverters vs 12% of controls. More controls than seroconverters tested in response to risk behaviour (70% vs 50%) or from a desire to know their status (34% vs 12%). Among seroconverters, 76% reported 'flu-like' illness during the time period of infection, 66% had symptoms consistent with SPHI, and 35% reported a physician's diagnosis of SPHI. Compared to seroconverters with undiagnosed SPHI, more of those diagnosed with SPHI had rash (odds ratio = 4.5). SPHI plays a significant role in HIV testing and subsequent early diagnosis in this population. More seroconversions could be diagnosed with better patient and physician awareness of its symptoms.

Perceived HIV risk, actual sexual HIV risk and willingness to take pre-exposure prophylaxis among men who have sex with men in Toronto, Canada

Pre-exposure prophylaxis (PrEP) reduces HIV acquisition. Our goal was to determine the willingness of men who have sex with men (MSM) to take PrEP given perceived and actual HIV risk. HIV-negative MSM were recruited from September 2010 to June 2012 and asked about PrEP willingness and perceived HIV risk. Actual sexual HIV risk was measured by three condom-use components generated through principal components analysis. General HIV risk was measured using the HIV Incidence Risk Index for MSM (HIRI-MSM). Model 1 measured PrEP willingness given perceived and actual sexual HIV risk. Model 2 included actual HIV sexual risk, perceived HIV risk and general HIV risk. Model 3 removed actual sexual HIV risk. We recruited 150 HIV-negative MSM. About 55% were willing to take PrEP. Reasons for PrEP unwillingness were: low perceived risk (64%), side-effect concerns (44%), daily pill burden (16%) and efficacy concerns (4%). Model 1: MSM with high compared to low actual sexual HIV risk were more willing to use PrEP (OR 27.11, 95% CI 1.33-554.43) after adjusting for perceived risk, which was not significantly associated with PrEP willingness (OR 4.79, 95% CI 0.72-31.96). Model 2: MSM with high compared to low actual sexual HIV risk were more willing to use PrEP (OR 29.85, 95% CI 1.39-640.53) after adjusting for perceived and general HIV risk, neither of which was significantly associated with PrEP willingness (OR 5.07, 95% CI 0.73-35.09) and (OR 1.58, 95% CI 0.37-6.79), respectively. Model 3: After removing actual sexual HIV risk, MSM with high compared to low perceived risk were more willing to use PrEP (OR 6.85, 95% CI 1.23-38.05), and the HIRI-MSM general risk index was not associated with PrEP willingness (OR 1.87, 95% CI 0.54-6.54). Therefore, actual sexual HIV risk was the best predictor of PrEP willingness and general HIV risk did not inform PrEP willingness.

Actual sexual risk and perceived risk of HIV acquisition among HIV-negative men who have sex with men in Toronto, Canada

Background

Theory suggests that perceived human immunodeficiency virus (HIV) risk and actual HIV risk behaviour are cyclical whereby engaging in high risk behaviour can increase perceived risk, which initiates precautionary behaviour that reduces actual risk, and with time reduces perceived risk. While current perceived risk may impact future actual risk, it is less clear how previous actual risk shapes current perceived risk. If individuals do not base their current perceived risk on past behaviour, they lose the protective effect of perceived risk motivating precautionary behaviour. Our goal was to determine the impact of actual risk on perceived risk.

Methods

Sexually active men who have sex with men (MSM) were recruited at the Maple Leaf Medical Clinic in downtown Toronto from September 2010 to June 2012. Participants completed a socio-behavioural questionnaire using an Audio Computer Assisted Self-Interview (ACASI). Actual HIV risk (primary predictor) was constructed by applying principal component analysis (PCA) to eight sexual risk survey questions and comprised three components which reflected sex with casual partners, sex with HIV-positive regular partners and sex with HIV unknown status regular partners. Perceived HIV risk (outcome) was measured by asking participants what the chances were that they would ever get HIV. Multivariable logistic regression was used to measure the association between actual and perceived HIV risk.

Results

One hundred and fifty HIV-negative MSM were recruited (median age 44.5 years [IQR 37–50 years]). Twenty percent of MSM perceived their HIV risk to be high. The odds of having a high perceived risk was significantly higher in those with high actual HIV risk indicated by low condom use with an HIV-positive regular partner compared to those with low actual HIV risk indicated by high condom use with an HIV-positive regular partner (Odds Ratio (OR) 18.33, 95 % confidence interval (CI) 1.65–203.45). Older age was associated with lower perceived risk but only age 40–49 compared to less than 30 was statistically significant (OR 0.12, 95 % CI 0.016–0.86). The odds of having high perceived risk was significantly associated with men who used poppers in the previous 6 months compared to those who did not use poppers (OR 5.64, 95 % CI 1.20–26.48).

Conclusions

Perceived HIV risk increased significantly as condom use with an HIV-positive regular partner decreased. However, perceived HIV risk was not associated with condom use with casual partners or HIV unknown status regular partners, even though these behaviours could be considered risky. The relationship between perceived and actual risk in HIV studies is complex and has implications on how health care workers address the issue of risky sexual behaviour and perceived risk.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-2859-6) contains supplementary material, which is available to authorized users.

Impact evaluation of a community-based intervention to reduce risky sexual behaviour among female sex workers in Shanghai, China

Background

Female sex workers (FSWs) are at risk for sexually transmitted infections (STIs), including HIV. We implemented an HIV/STI preventive intervention among FSWs in Shanghai that aimed to increase condom use, improve HIV knowledge, and reduce STI and HIV incidence.

Methods

From six districts in Shanghai, 750 randomly selected venue-based FSWs were allocated to either a behavioural intervention or control group. In the intervention and control groups, 221 and 278 participants, respectively, had at least one follow-up at three or six months. In analysis, we randomly selected 57 lost to follow-up cases in the intervention group and imputed baseline values to equalize the arms at n = 278 (74.1% follow-up rate in each group). The impacts of the intervention on condom use, HIV/STI risk perception and knowledge, and STI incidence were assessed using either a logistic or linear model, adjusting for the baseline measure of the outcome and venue type.

Results

The intervention improved consistent condom use with any partner type in the previous month (AOR = 2.09, 95% CI, 1.43-3.04, p = 0.0001). Consistent condom use with clients in the three most recent sex acts increased in both arms, and with primary partners in the intervention arm, but there was no difference between groups after adjusting for baseline condom use and venue type. There were no differences in cumulative incidence of any STI (i.e., chlamydia, gonorrhoea, syphilis) between groups. HIV transmission knowledge (p = 0.0001), condom use skill (p = 0.0421), and self-efficacy for using condoms (p = 0.0071) were improved by the intervention. HIV-related stigma declined (p = 0.0119) and HIV and STI risk perception were improved (4.6 to 13.9%, and 9.4 to 20.0%, respectively). The intervention was associated with these improvements after adjusting for the baseline measure and venue type.

Conclusion

Following a preventive intervention among Shanghai FSWs, our findings demonstrate that a simple, community-based educational intervention improved overall condom use, HIV and STI knowledge, and attitudes in relation to HIV/AIDS. The intervention should be implemented widely after tailoring educational materials regarding condom negotiation with different partner types (i.e., commercial sex clients and primary partners).

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1439-5) contains supplementary material, which is available to authorized users.

Modest rise in chlamydia and gonorrhoea testing did not increase case detection in a clinical HIV cohort in Ontario, Canada

OBJECTIVES

We described patterns of testing for chlamydia and gonorrhoea infection among persons in specialty HIV care in Ontario, Canada, from 2008 to 2011.

METHODS

We analysed data from 3165 participants in the OHTN Cohort Study attending one of seven specialty HIV care clinics. We obtained chlamydia and gonorrhoea test results via record linkage with the provincial public health laboratory. We estimated the proportion of participants who underwent testing annually, the positivity rate among those tested and the proportion diagnosed with chlamydia or gonorrhoea among all under observation. We explored risk factors for testing and diagnosis using multiple logistic regression analysis.

RESULTS

The proportion tested annually rose from 15.2% (95% CI 13.6% to 16.7%) in 2008 to 27.0% (95% CI 25.3% to 28.6%) in 2011 (p<0.0001). Virtually all were urine-based nucleic acid amplification tests. Testing was more common among men who have sex with men (MSM), younger adults, Toronto residents, persons attending primary care clinics and persons who had tested in the previous year or who had more clinic visits in the current year. We observed a decrease in test positivity rates over time. However, the annual proportion diagnosed remained stable and in 2011 this was 0.97% (95% CI 0.61% to 1.3%) and 0.79% (95% CI 0.46% to 1.1%) for chlamydia and gonorrhoea, respectively. Virtually all cases were among MSM.

CONCLUSIONS

Chlamydia and gonorrhoea testing increased over time while test positivity rates declined and the overall proportion diagnosed remained stable, suggesting that the modest increase in testing did not improve case detection.

HIV transmission among men who have sex with men due to condom failure

Background

Despite preventive efforts, HIV incidence remains high among men who have sex with men (MSM) in industrialized countries. Condoms are an important element in prevention but, given the high frequency of condom use and their imperfect effectiveness, a substantial number and proportion of HIV transmissions may occur despite condoms. We developed a model to examine this hypothesis.

Methods

We used estimates of annual prevalent and incident HIV infections for MSM in Ontario. For HIV-negative men, we applied frequencies of sexual episodes and per-contact HIV transmission risks of receptive and insertive anal sex with and without a condom and oral sex without a condom. We factored in the proportion of HIV-infected partners receiving antiretroviral therapy and its impact in reducing transmissibility. We used Monte-Carlo simulation to determine the plausible range for the proportion of HIV transmissions for each sexual practice.

Results

Among Ontario MSM in 2009, an estimated 92,963 HIV-negative men had 1,184,343 episodes of anal sex with a condom and 117,133 anal sex acts without a condom with an HIV-positive partner. Of the 693 new HIV infections, 51% were through anal sex with a condom, 33% anal sex without a condom and 16% oral sex. For anal sex with a condom, the 95% confidence limits were 17% and 77%.

Conclusions

The proportion of HIV infections related to condom failure appears substantial and higher than previously thought. That 51% of transmissions occur despite condom use may be conservative (i.e. low) since we used a relatively high estimate (87.1%) for condom effectiveness. If condom effectiveness were closer to 70%, a value estimated from a recent CDC study, the number and proportion of HIV transmissions occurring despite condom use would be much higher. Therefore, while condom use should continue to be promoted and enhanced, this alone is unlikely to stem the tide of HIV infection among MSM.

Factors responsible for mother-to-child HIV transmission in Ontario, Canada, 1996-2008

OBJECTIVE

Despite a high uptake of HIV screening and anti-retroviral prophylaxis in Ontario, several cases of mother-to-child (MTC) transmission occur every year. We wished to examine the modifiable factors responsible for MTC HIV transmission in Ontario, in particular HIV testing, antiretroviral prophylaxis and breast-feeding.

METHODS

Using the Ontario data from the Canadian Perinatal HIV Surveillance Program, we examined potential correlates of late maternal HIV diagnosis (i.e., diagnosed at or after delivery) among women delivering from 1996 to 2008. To better understand the factors responsible for MTC HIV transmission, we reviewed the medical charts of 35 HIV-infected infants born in Ontario.

RESULTS

Among the 645 HIV-infected mothers, 85 (13.2%) had late HIV diagnosis. The proportion with late HIV diagnosis significantly decreased during the study period, but did not differ by race/ethnicity group or maternal exposure category. With respect to the mothers of the 35 HIV-infected infants, 27 (77%) were diagnosed with HIV at or after delivery. The reasons no prenatal HIV test was performed were: not offered, offered but refused, no prenatal care, denied HIV testing history, and offered but not done. Reasons for no or incomplete antiretroviral  prophylaxis (ARP) among eight mothers diagnosed prior to or during pregnancy were: refused or non-compliant with ARP, and failed to inform care provider of HIV status.

CONCLUSIONS

Despite the recommendation for universal prenatal HIV counseling and voluntary testing adopted in Ontario, MTC transmission continued to occur, mostly due to late HIV diagnosis of the mother. Future work to reduce perinatal HIV infection should focus on enhancing timely HIV testing of pregnant women.

The epidemiology of sexually transmitted co-infections in HIV-positive and HIV-negative African-Caribbean women in Toronto

BACKGROUND

HIV disproportionately affects African-Caribbean women in Canada but the frequency and distribution of sexually transmitted infections in this community have not been previously studied.

METHODS

We recruited women based on HIV status through a Toronto community health centre. Participants completed a socio-behavioural questionnaire using Audio Computer Assisted Self-Interview (ACASI) and provided blood for syphilis, HIV, hepatitis B and C, herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and human cytomegalovirus (CMV) serology, urine for chlamydia and gonorrhea molecular testing and vaginal secretions for bacterial vaginosis (BV) and human papillomavirus (HPV). Differences in prevalence were assessed for statistical significance using chi-square.

RESULTS

We recruited 126 HIV-positive and 291 HIV-negative women, with a median age of 40 and 31 years, respectively (p < 0.001). Active HBV infection and lifetime exposure to HBV infection were more common in HIV-positive women (4.8% vs. 0.34%, p = 0.004; and 47.6% vs. 21.2%, p < 0.0001), as was a self-reported history of HBV vaccination (66.1% vs. 44.0%, p = 0.0001). Classical STIs were rare in both groups; BV prevalence was low and did not vary by HIV status. HSV-2 infection was markedly more frequent in HIV-positive (86.3%) than HIV-negative (46.6%) women (p < 0.0001). Vaginal HPV infection was also more common in HIV-positive than in HIV-negative women (50.8% vs. 22.6%, p < 0.0001) as was infection with high-risk oncogenic HPV types (48.4% vs. 17.3%, p < 0.0001).

CONCLUSIONS

Classical STIs were infrequent in this clinic-based population of African-Caribbean women in Toronto. However, HSV-2 prevalence was higher than that reported in previous studies in the general Canadian population and was strongly associated with HIV infection, as was infection with hepatitis B and HPV.

Patterns of syphilis testing in a large cohort of HIV patients in Ontario, Canada, 2000-2009

Background

Since 2000, reported syphilis cases increased ten-fold in Canada, particularly among men who have sex with men (MSM) co-infected with HIV. We characterized temporal patterns of of syphilis testing in a large cohort of HIV patients in Ontario, Canada.

Methods

We analyzed data from a multi-site cohort of people in HIV care from 2000 to 2009. Data were obtained from medical charts, interviews and record linkage with the syphilis test database at the Public Health Ontario Laboratories. We estimated the proportion that had syphilis testing at least once per year and the period and annual prevalence of reactive tests.

Results

Among 4232 participants, the annual proportion tested rose from 2.7% (95%CI 1.9, 3.5) in 2000 to 54.6% (95%CI 52.9, 56.3) in 2009. Testing was most common for participants who were men who have sex with men (MSM), aged <30, recently diagnosed with HIV, were antiretroviral treatment naive, had routine HIV lab testing at least twice in that year, or tested for syphilis in the preceding year. The proportion with at least one reactive test in 2000–09 was 21.0% (95%CI 19.4, 22.7) for MSM, 5.3% (95%CI 3.3, 7.4) for non-MSM males, and 2.6% (95%CI 1.2, 4.0) for women. Among MSM, the annual prevalence of reactive syphilis tests with high RPR titre (≥1:16) peaked at 3.8% in 2009.

Conclusions

The burden of syphilis co-infection rose considerably among HIV-positive MSM, such that by 2009, at least 1 in 5 men had laboratory evidence of current or past infection. Interventions may be needed to boost syphilis testing to achieve goals set by guidelines even in settings with universal health care.

Black gay men as sexual subjects: race, racialisation and the social relations of sex among Black gay men in Toronto

In this study of Black gay and bisexual men in Toronto, sexually active survey participants reported on their sexual behaviours with male partners of different ethnoracial backgrounds, and interview participants reflected on how their sexual relationships emerged in the context of race and interracial desire. Most survey participants reported sexual relationships with other Black men. Participants were more likely to be insertive with White and other ethnoracial men than with Black men. A significant number of participants who were receptive or versatile with Black partners switched to the insertive role when their sexual partners were not Black. Interview participants ascribed a sense of fulfilment to their sexual relationships with other Black men, but avoided relationships with White men or interpreted such relationships as either purely sexual and/or inflected by their racialised objectification. Others avoided sexual relationships with other Black men or preferred relationships with White men, sometimes in opposition to experiences of oppressive masculinity from some Black partners but mindful of the possibility of racialised encounters with their White partners. Study participants emerge as informed sexual subjects, self-conscious about their sexual relationships and variously inclined to negotiate or resist racialisation and oppression in the private and public spheres.

Nondisclosure prosecutions and population health outcomes: examining HIV testing, HIV diagnoses, and the attitudes of men who have sex with men following nondisclosure prosecution media releases in Ottawa, Canada

BACKGROUND

During the past decade, the intersection of HIV and criminal law has become increasingly discussed. The majority of studies to date have approached this topic from a sociological or legal perspective. As a result, the potential effect of nondisclosure prosecutions on population health and HIV prevention work remains mostly unknown.

METHODS

A descriptive quantitative-qualitative study was undertaken to examine HIV testing, HIV diagnoses, and the attitudes of men who have sex with men following regional media releases about a local nondisclosure prosecution. As part of this study, first, we reviewed the trends in HIV testing and HIV diagnoses from 2008 through 2011 in Ottawa, Canada. Second, we explored the attitudes and beliefs of local MSM about HIV, HIV prevention, HIV serostatus disclosure, nondisclosure prosecutions, and public health.

RESULTS

Quantitatively, the findings of this study revealed that, in comparison to the period preceding the media releases about a local nondisclosure prosecution, HIV testing and HIV diagnoses among men who have sex with men did not significantly change after the media releases of interest. Qualitatively, a subgroup of 27 men who have sex with men (12 HIV-positive, 15 HIV-negative) noted their beliefs that the local public health department openly shares information about people living with HIV with the police. Moreover, some HIV-positive participants stated that this perceived association between the local public health department and police services caused them to not access public health department services, notwithstanding their desires to seek assistance in maintaining safer sexual practices.

CONCLUSIONS

Nondisclosure prosecutions likely undermine HIV prevention efforts.

High uptake of HIV testing in pregnant women in Ontario, Canada

In 1999, Ontario implemented a policy to offer HIV counseling and testing to all pregnant women and undertook measures to increase HIV testing. We evaluated the effectiveness of the new policy by examining HIV test uptake, the number of HIV-infected women identified and, in 2002, the HIV rate in women not tested during prenatal care. We analyzed test uptake among women receiving prenatal care from 1999 to 2010. We examined HIV test uptake and HIV rate by year, age and health region. In an anonymous, unlinked study, we determined the HIV rate in pregnant women not tested. Prenatal HIV test uptake in Ontario increased dramatically, from 33% in the first quarter of 1999 to 96% in 2010. Test uptake was highest in younger women but increased in all age groups. All health regions improved and experienced similar test uptake in recent years. The HIV rate among pregnant women tested in 2010 was 0.13/1,000; in Toronto, the rate was 0.28 per 1,000. In the 2002 unlinked study, the HIV rate was 0.62/1,000 among women not tested in pregnancy compared to 0.31/1,000 among tested women. HIV incidence among women who tested more than once was 0.05/1,000 person-years. In response to the new policy in Ontario, prenatal HIV testing uptake improved dramatically among women in all age groups and health regions. A reminder to physicians who had not ordered a prenatal HIV test appeared to be very effective. In 2002, the HIV rate in women who were not tested was twice that of tested women: though 77% of pregnant women had been tested, only 63% of HIV-infected women were tested. HIV testing uptake was estimated at 98% in 2010.

Characterizing viral subtypes to assess patterns of HIV transmission

We characterized HIV-1 subtypes among 204 persons newly diagnosed with HIV in Ontario from 2003 to 2005 using samples from the Canadian HIV Strain and Drug Resistance Surveillance Program. We examined HIV-1 subtype by demographic characteristics and exposure category, and determined independent predictors of infection with a non-B HIV subtype using multivariate logistic regression. The distribution of HIV subtypes was: B 77.0%, C 10.3%, AG 4.9%, A 2.5%, AE 2.5% and others 3.0%. Overall, 23.0% were non-B, greater in women than in men (62.8% versus 12.4%, P < 0.0001) and persons under 35 years (31.1% versus 18.5% in those ≥35, P = 0.04). Non-B subtype was predominant (78.9%) among persons from HIV-endemic regions and considerable (28.6%) among other persons infected heterosexually. In multivariate modelling adjusted for gender, non-B subtype was significantly associated with birth in an HIV-endemic region (adjusted odds ratio [aOR] 59.2, P < 0.0001) and heterosexual exposure (aOR 6.3, P = 0.02). Additionally, compared with men who had sex with men, non-B subtype was greater among heterosexual women (aOR 17.8, P < 0.001) and women who injected drugs (injection drug use, aOR 13.4, P = 0.01). We found a non-negligible proportion of non-B subtypes among women infected heterosexually not from HIV-endemic countries, providing interesting insights into HIV transmission patterns.

The impact of infection on population health: results of the Ontario burden of infectious diseases study

BACKGROUND

Evidence-based priority setting is increasingly important for rationally distributing scarce health resources and for guiding future health research. We sought to quantify the contribution of a wide range of infectious diseases to the overall infectious disease burden in a high-income setting.

METHODOLOGY/PRINCIPAL FINDINGS

We used health-adjusted life years (HALYs), a composite measure comprising premature mortality and reduced functioning due to disease, to estimate the burden of 51 infectious diseases and associated syndromes in Ontario using 2005-2007 data. Deaths were estimated from vital statistics data and disease incidence was estimated from reportable disease, healthcare utilization, and cancer registry data, supplemented by local modeling studies and national and international epidemiologic studies. The 51 infectious agents and associated syndromes accounted for 729 lost HALYs, 44.2 deaths, and 58,987 incident cases per 100,000 population annually. The most burdensome infectious agents were: hepatitis C virus, Streptococcus pneumoniae, Escherichia coli, human papillomavirus, hepatitis B virus, human immunodeficiency virus, Staphylococcus aureus, influenza virus, Clostridium difficile, and rhinovirus. The top five, ten, and 20 pathogens accounted for 46%, 67%, and 75% of the total infectious disease burden, respectively. Marked sex-specific differences in disease burden were observed for some pathogens. The main limitations of this study were the exclusion of certain infectious diseases due to data availability issues, not considering the impact of co-infections and co-morbidity, and the inability to assess the burden of milder infections that do not result in healthcare utilization.

CONCLUSIONS/SIGNIFICANCE

Infectious diseases continue to cause a substantial health burden in high-income settings such as Ontario. Most of this burden is attributable to a relatively small number of infectious agents, for which many effective interventions have been previously identified. Therefore, these findings should be used to guide public health policy, planning, and research.

Comparisons of disparities and risks of HIV infection in black and other men who have sex with men in Canada, UK, and USA: a meta-analysis

BACKGROUND

We did a meta-analysis to assess factors associated with disparities in HIV infection in black men who have sex with men (MSM) in Canada, the UK, and the USA.

METHODS

We searched Embase, Medline, Google Scholar, and online conference proceedings from Jan 1, 1981, to Dec 31, 2011, for racial comparative studies with quantitative outcomes associated with HIV risk or HIV infection. Key words and Medical Subject Headings (US National Library of Medicine) relevant to race were cross-referenced with citations pertinent to homosexuality in Canada, the UK, and the USA. Data were aggregated across studies for every outcome of interest to estimate overall effect sizes, which were converted into summary ORs for 106,148 black MSM relative to 581,577 other MSM.

FINDINGS

We analysed seven studies from Canada, 13 from the UK, and 174 from the USA. In every country, black MSM were as likely to engage similarly in serodiscordant unprotected sex as other MSM. Black MSM in Canada and the USA were less likely than other MSM to have a history of substance use (odds ratio, OR, 0·53, 95% CI 0·38-0·75, for Canada and 0·67, 0·50-0·92, for the USA). Black MSM in the UK (1·86, 1·58-2·18) and the USA (3·00, 2·06-4·40) were more likely to be HIV positive than were other MSM, but HIV-positive black MSM in each country were less likely (22% in the UK and 60% in the USA) to initiate combination antiretroviral therapy (cART) than other HIV-positive MSM. US HIV-positive black MSM were also less likely to have health insurance, have a high CD4 count, adhere to cART, or be virally suppressed than were other US HIV-positive MSM. Notably, despite a two-fold greater odds of having any structural barrier that increases HIV risk (eg, unemployment, low income, previous incarceration, or less education) compared with other US MSM, US black MSM were more likely to report any preventive behaviour against HIV infection (1·39, 1·23-1·57). For outcomes associated with HIV infection, disparities were greatest for US black MSM versus other MSM for structural barriers, sex partner demographics (eg, age, race), and HIV care outcomes, whereas disparities were least for sexual risk outcomes.

INTERPRETATION

Similar racial disparities in HIV and sexually transmitted infections and cART initiation are seen in MSM in the UK and the USA. Elimination of disparities in HIV infection in black MSM cannot be accomplished without addressing structural barriers or differences in HIV clinical care access and outcomes.

FUNDING

None.

The impact of stressful life events on unprotected anal intercourse among gay and bisexual men

We investigated the hypothesis that gay and bisexual men experiencing stressful life events are more likely to engage in risky sexual behavior. Data were from a cohort study of 155 HIV-positive and 207 HIV-negative men in Ontario, Canada (1998-2007). We quantified the relation between stressful life events and unprotected anal intercourse with a non-regular partner. In the past 6 months, 19% reported unprotected intercourse (HIV+: 28%; HIV-: 13%) and 58% reported one or more stressful life events (HIV+: 64%; HIV-: 55%). Among HIV-negative men, the odds of unprotected intercourse increased by 1.15 for each additional event (95%CI 1.06, 1.24). Among HIV-positive men, those who reported the event "problems due to alcohol or drugs" were 1.80 (95%CI 1.27, 2.56) times more likely to report unprotected intercourse. Interventions to assist men to cope with stress may help to prevent population spread of HIV and improve overall health.

The MaBwana Black men's study: community and belonging in the lives of African, Caribbean and other Black gay men in Toronto

In Canada, there is a paucity of research aimed at understanding Black gay men and the antecedents to risk factors for HIV. This study is an attempt to move beyond risk factor analysis and explore the role of sexual and ethnic communities in the lives of these men. The study utilized a community-based research and critical race theory approach. Semi-structured interviews were conducted with eight key informants to augment our understanding of Black gay men and to facilitate recruitment of participants. In-depth interviews were done with 24 Black gay men. Our data showed that the construction of community for Black gay men is challenged by their social and cultural environment. However, these men use their resilience to navigate gay social networks. Black gay men expressed a sense of abjuration from both gay and Black communities because of homophobia and racism. It is essential for health and social programmers to understand how Black gay men interact with Black and gay communities and the complexities of their interactions in creating outreach educational, preventive and support services.

Correlates of unprotected anal sex at last sexual episode: analysis from a surveillance study of men who have sex with men in Montreal

Recent increases in rates of unprotected anal sex (UAS) among men who have sex with men (MSM) signal the need to continually refine our understanding of factors associated with risky sexual behavior. Data were collected using a questionnaire eliciting information about the last sexual episode (LSE) with another man in the past 6 months. Logistic regression was used to identify both event-level and background correlates of UAS at LSE. 965 participants who reported having sex with a partner with whom they were not in a couple relationship at LSE were studied. Several event-level variables were significantly associated with UAS after adjusting for background factors, including finding the partner at LSE sexually attractive and using alcohol or cocaine at LSE. Our findings parallel the results of other HIV prevention studies which have highlighted the importance of interpersonal factors that influence risk-taking at the moment of a sexual act among MSM.

Patterns of HIV testing among Ontario physicians

OBJECTIVE

HIV testing is important for HIV prevention and control. Nevertheless, approximately 35% of HIV infections in Ontario remain undiagnosed. We examined patterns of HIV testing among physicians to determine provider-related factors associated with HIV testing in Ontario.

METHODS

Providers identified from HIV test requisitions submitted to the Ontario Public Health Laboratory in 2006 were linked to a database of Ontario physicians using probabilistic matching. We examined HIV testing frequency by demographic characteristics and physician specialty. In multivariate logistic regression, we assessed factors associated with high testing frequency (20+ tests).

RESULTS

12,477 physicians (59.3% of Ontario physicians) prescribed at least one HIV test in 2006; the proportion was highest in Central East/other (72.4%) and Northern (69.4%) regions compared to others (53.7-58.7%), and highest among the most recent graduates (68.4% versus 59.0% among earlier graduates). A substantial proportion of physicians in family medicine/general practice (83.6%), obstetrics/gynecology (82.1%) and internal medicine (47.7%) prescribed HIV testing. Overall, most physicians (67.5%) prescribed fewer than 20 tests. High testing frequency was significantly associated with practice in Toronto (AOR 2.95), Central East/other (AOR 2.02), or Ottawa region (AOR 2.28), and specialty in family medicine/general practice (AOR 11.47), obstetrics/gynecology (AOR 6.31) or internal medicine (AOR 1.37). Physician sex and graduation country were not associated with high testing in multivariate regression. Of 361,609 tests, 1,048 (0.29%) were HIV-positive; 436 physicians (3.5%) had at least one HIV-positive result.

CONCLUSION

HIV testing among Ontario physicians varied substantially by health region, graduation year and specialty. These factors should be considered when delivering continuing medical education on HIV testing.

Accuracy of serological assays for detection of recent infection with HIV and estimation of population incidence: a systematic review

We systematically reviewed the accuracy of serological tests for recent infections with HIV that have become widely used for measuring population patterns incidence of HIV. Across 13 different assays, sensitivity to detect recent infections ranged from 42-100% (median 89%). Specificity for detecting established infections was between 49.5% and 100% (median 86.8%) and was higher for infections of durations longer than 1 year (median 98%, range 31.5-100.0). For four different assays, comparisons were made between assay-derived population incidence estimates and a reference incidence estimate. The median percentage difference between the assay-derived incidence and reference incidence was 26.0%. Serological assays have reasonable sensitivity for the detection of recent infection with HIV, but are vulnerable to misclassifying established infections as recent-potentially leading to biases in incidence estimates. This conclusion is highly qualified by the apparent absence of a standardised approach to assay evaluation. There is an urgent need for an internationally agreed framework for evaluating and comparing these tests.

Prenatal HIV testing: women's experiences of informed consent in Toronto, Ontario

OBJECTIVE

All Canadian jurisdictions have human immunodeficiency virus (HIV) testing programs requiring that clinicians discuss HIV testing with all pregnant women and seek their consent to be tested. Our goal was to evaluate how the informed consent process was being carried out in Ontario.

METHODS

Between November 2002 and February 2004, women in postpartum wards in three Toronto teaching hospitals were invited to participate in the study. A structured questionnaire was administered on the ward, medical records were reviewed, and data from the Central Public Health Laboratory were examined to verify whether or not the women had been tested.

RESULTS

Of 446 women invited, 299 (67%) participated. All except one participant had at least one prenatal visit, and 92% had more than five visits. Seventy-four percent of participants recalled a clinician talking to them about testing, and 70% of these felt that they were given the option to refuse the test. Twenty-one women overall (7%) believed that they were not tested during pregnancy or were not certain whether they had been tested or not, but actually had been tested. Women who felt that their care provider did not have an opinion about whether they should undergo testing were more likely to decline. Eighty-six percent were completely satisfied with the testing experience.

CONCLUSION

Informed consent for prenatal HIV testing is generally being obtained in a manner consistent with provincial guidelines. Our findings raise concern, however, that a significant number of women are not offered testing or in some cases are tested without their consent. Increases in testing rates could be achieved by offering the test to all women and emphasizing that carrying out testing is a recommended part of medical care.

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.

HIV and ethnicity in Canada: is the HIV risk-taking behaviour of young foreign-born MSM similar to Canadian born MSM?

There is a dearth of information on the HIV risk-taking behaviour of foreign-born men who have sex with men (MSM) in Canada. This study focused on identifying sexual risk behaviour among MSM who immigrated to Canada and compared them to MSM who were born in Canada. Baseline data from the Omega Cohort in Montreal and the Vanguard Project in Vancouver were combined to form four ethnicity/race analytical categories (n = 1,148): White born in Canada (WBIC), White born outside of Canada, non-White born in Canada (NBIC) and non-White born outside of Canada (NBOC). Psychological, demographic and sexual behaviour characteristics of the groups were similar except: NBOC were more likely to be unemployed, less likely to be tattooed, had fewer bisexual experiences and less likely worried of insufficient funds. WBOC were more likely to report unprotected sex with seropositives and more likely to have had unprotected sex while travelling. NBIC were more likely to have ever sold sex and to have had body piercing. WBOC are at high risk of acquiring as well as transmitting HIV. It is important to consider place of birth in addition to ethnicity when developing programmes to prevent the transmission of HIV.

Medical Records and Women’s Self-Report Are Not Reliable Sources for Determining Whether Prenatal HIV Testing Was Done

OBJECTIVE

To determine whether medical records and the self-report of a postpartum patient provide reliable information about whether or not prenatal HIV testing has been done.

METHODS

Women on the postpartum wards at three Toronto teaching hospitals who gave informed consent were included in the study. The presence or absence of prenatal HIV testing was determined by interviews with postpartum women, review of hospital charts, and search of the Public Health Provincial Laboratory and Prenatal Testing databases.

RESULTS

Two hundred ninety-nine women were enrolled. All had had at least one prenatal visit, and 92% had copies of prenatal records in their hospital charts. Health records and patient reports were both unreliable for determining who had and who had not had HIV testing. HIV status was documented on 55% of the charts; on 46% it was noted that testing was performed, and on 46% there was documentation of pre& or post&test counselling. In interviews, 73% of the women reported having an HIV test during this pregnancy. Using the laboratory databases as the gold standard of whether testing had truly been done, medical record sensitivity and specificity were 65% and 62% respectively, and self-report sensitivity and specificity were 87% and 52% respectively. Using medical records resulted in an underestimation and self-reports an overestimation of the number of women who had been tested.

CONCLUSIONS

Both medical records and patient self-report are unreliable at the time of labour and delivery for determining whether or not a woman has been tested for HIV in pregnancy. Clinical and public health decisions may therefore be compromised by a lack of accurate testing information at the bedside.

Nonnegligible increasing temporal trends in unprotected anal intercourse among men who have sexual relations with other men in montreal

OBJECTIVE

To determine temporal trends in unprotected anal intercourse (UAI) among men who have sex with men (MSM) participating in the Omega Cohort Study, 1997 through 2003.

METHODS

The Omega Cohort Study was a longitudinal study of HIV-negative MSM aged 16 years or older and living in Montreal. Participants completed self-administered questionnaires and interviews every 6 months. Trend analysis using the generalized estimating equation was done for length of cohort membership (visits) and by calendar time for all visits per type of sexual partner. Odds ratios (ORs) were calculated to measure the odds of increasing UAI per 6-month period.

RESULTS

Among subjects who were followed for at least 4 years, UAI increased with regular seroconcordant partners (OR = 1.06, 95% confidence interval [CI]: 1.04 to 1.09) and any type of partner (OR = 1.05, 95% CI: 1.03 to 1.07). There was a nonnegligible increase in UAI with casual partners (OR = 1.05, 95% CI: 1.01 to 1.09). For the analysis by calendar time, there were increases in UAI between regular seroconcordant partners (OR = 1.04, 95% CI: 1.02 to 1.05) and any type of partner (OR = 1.03, 95% CI: 1.02 to 1.04). There were nonnegligible increases in UAI with casual partners (OR = 1.03, 95% CI: 1.00 to 1.05) and with any type of partner except a regular seroconcordant partner from 15.7% to 18.8% (OR = 1.02, 95% CI: 1.00 to 1.04).

CONCLUSIONS

There was a nonnegligible and consistent increase in UAI among Omega Cohort Study participants between 1997 and 2003. Continuous trend analysis is important because it allows us to follow UAI closely and to implement intervention strategies that may help to stop or reduce the present trend.

Trends in HIV-1 in young adults in south India from 2000 to 2004: a prevalence study

BACKGROUND

Major increases in HIV-1 prevalence in India have been predicted. Incident infections need to be tracked to understand the epidemic's course, especially in some southern states of India where the epidemic is more advanced. To estimate incidence, we investigated the prevalence of HIV-1 in young people attending antenatal and sexually transmitted infection (STI) clinics in India.

METHODS

We analysed unlinked, anonymous HIV-1 prevalence data from 294 050 women attending 216 antenatal clinics and 58 790 men attending 132 STI clinics in 2000-04. Southern and northern states were analysed separately.

FINDINGS

The age-standardised HIV-1 prevalence in women aged 15-24 years in southern states fell from 1.7% to 1.1% in 2000-04 (relative reduction 35%; p(trend)<0.0001, yearly reduction 11%), but did not fall significantly in women aged 25-34 years. Reductions in women aged 15-24 years were seen in key demographic groups and were similar in sites tested continuously or in all sites. Prevalence in the north was about a fifth of that in the south, with no significant decreases (or increases) in 2000-04. Prevalence fell in men aged 20-29 years attending STI clinics in the south (p(trend)<0.0001), including those with ulcerative STIs (p(trend)=0.0008), but reductions were more modest in their northern counterparts.

INTERPRETATION

A reduction of more than a third in HIV-1 prevalence in 2000-04 in young women in south India seems realistic, and is not easily attributable to bias or to mortality. This fall is probably due to rising condom use by men and female sex workers in south India, and thus reduced transmission to wives. Expansion of peer-based condom and education programmes for sex workers remains a top priority to control HIV-1 in India.

Nonnegligible Increasing Temporal Trends in Unprotected Anal Intercourse Among Men Who Have Sexual Relations With Other Men in Montreal

OBJECTIVE

The objective of this study is to determine temporal trends in unprotected anal intercourse (UAI) among men who have sex with other men (MSM) participating in the Omega Cohort Study, 1997-2003.

METHODS

The Omega Cohort Study was a longitudinal study of HIV-negative MSM aged 16 years or older and living in Montreal. Participants completed self-administered questionnaires and interviews every 6 months. Trend analysis using the generalized estimating equation was done for length of cohort membership (visits) and by calendar time for all visits, per type of sexual partner. Odds ratios (ORs) were calculated to measure the odds of increasing UAI per 6-month period.

RESULTS

Among subjects who were followed for at least 4 years, UAI increased with regular seroconcordant partners (OR, 1.06, 95% CI 1.04-1.09), and any type of partner (OR, 1.05, 95% CI 1.03- 1.07). There was a nonnegligible increase in UAI with casual partners (OR, 1.05; 95% CI, 1.01-1.09). For the analysis by calendar time, there were increases in UAI between with regular seroconcordant partners (OR, 1.04; 95% CI, 1.02-1.05) and any type of partner (OR, 1.03; 95% CI, 1.02-1.04). There were nonnegligible increases in UAI with casual partners (OR, 1.03; 95% CI, 1.00-1.05) and with any type of partner except regular seroconcordant partner from 15.7% to 18.8% (OR, 1.02; 95% CI, 1.00-1.04).

CONCLUSIONS

There was a nonnegligible and consistent increase in UAI among Omega participants, between 1997 and 2003. Continuous trend analysis is important because it allows us to closely follow UAI and to implement intervention strategies that may help to stop or reduce the present trend.

Sexual risk behaviour of Canadian participants in the first efficacy trial of a preventive HIV-1 vaccine

BACKGROUND

Phase I and phase II HIV-1 vaccine trials have revealed increases in risky sexual activity among study subjects during the trials, perhaps because the subjects believe that the vaccine being tested is efficacious; subjects may thus suffer harm from their participation. We evaluated the sexual behaviour of Canadian men who have sex with men (MSM) who participated in the phase III Vax004 trial of an HIV-1 vaccine.

METHODS

Using self-reports of sexual behaviours during the 6 months before trial entry as a baseline, we determined changes in reported sexual behaviour after 6, 12 and 18 months of participation in the trial.

RESULTS

Of 291 HIV-seronegative MSM enrolled from July to October 1999, 260 (89%) completed 18 months of follow-up, 19 (7%) experienced seroconversion, and 12 (4%) did not complete follow-up. Unprotected receptive anal intercourse during the previous 6 months with partners whose HIV-1 serostatus was positive or unknown was reported by 21% of men at enrollment and by 27% at any point during 18 months of follow-up. No increase in this behaviour from baseline was reported by participants, including among men who were motivated to enroll because of expected protection from HIV-1 infection, men who believed they had received the vaccine, men who believed that the vaccine had greater than 50% efficacy, or men who believed that they had received the vaccine and that vaccine efficacy was greater than 50%.

INTERPRETATION

MSM can be successfully enrolled in HIV-1 vaccine efficacy trials without evident increases in those sexual behaviours most associated with HIV-1 risk.

Potential cost-effectiveness of a preventive hepatitis C vaccine in high risk and average risk populations in Canada

Hepatitis C virus (HCV) vaccine development remains at an early stage. We explored the economic and health consequences of potential HCV vaccines by comparing universal vaccination with a hepatitis C vaccine to no vaccination in two groups: (1) injecting drug users (IDU); (2) all 12 year olds, using a Markov cohort simulation. Among IDUs, vaccination would avert 248 cases of HCV infection and 89 HCV-related deaths per 1000 individuals, and reduce costs. In average risk cohorts, vaccination did not reduce costs but was reasonably cost effective. These results provide encouragement to vaccine developers that a vaccine that is moderately effective and reasonably priced should not face economic barriers to implementation and will be attractive to third party payers.

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.

Epidemiologic Modeling to Evaluate Prevention of Mother???Infant HIV Transmission in Ontario

OBJECTIVES

To evaluate the impact of the Ontario HIV screening program to reduce mother-infant HIV transmission, this study estimated the proportion of preventable transmissions that were prevented.

METHODS

Using an iterative spreadsheet model, incidences of HIV infection, AIDS, and AIDS mortality in Ontario women were estimated by exposure category. The number of HIV-infected infants born to HIV-infected mothers was then estimated from conception and abortion rates of HIV-infected women of childbearing age and surveillance data. Finally, the proportion of HIV-infected mothers who received antiretroviral prophylaxis (ARP) was assessed.

RESULTS

HIV prevalence in 2001 among women of childbearing age was 1.05 per 1000. From 1984-2001, 764 infants were born to HIV-infected mothers and 180 were infected. From mid-1994-2001, 214 (39%) of the estimated 544 HIV-infected mothers were diagnosed; almost all received ARP. Of 118 preventable infections among infants born in this period, 39 (33%) were prevented. In 2001, only 46% of preventable infections were prevented and 11 preventable transmissions occurred.

CONCLUSIONS

HIV prevalence among women in Ontario increased >4-fold from 1990 to 2001. Fewer than half of HIV-infected mothers received ARP and preventable HIV infections continue to occur. Measures to further increase uptake of prenatal HIV screening must be instituted.

Delayed application of condoms is a risk factor for human immunodeficiency virus infection among homosexual and bisexual men

The objective of this analysis was to identify risk factors for recent human immunodeficiency virus (HIV) infection among homosexual and bisexual men in Ontario, Canada, during 1998-2001. Participants were recruited through the provincial HIV diagnostic laboratory and through physicians and community organizations. HIV test results were used to identify recent seroconverters (cases). A subsample of 183 men (62 cases and 121 controls) enrolled in the Polaris HIV Seroconversion Study as of June 2001 was analyzed. This analysis focused on sexual behaviors with partners who were HIV-positive or whose HIV status was unknown. In multiple logistic regression, independent risk factors were identified. Rates of unprotected receptive oral, insertive anal, and receptive anal sex and delayed application of condoms during receptive anal sex (RAS) were significantly higher among cases (97%, 41%, 53%, and 32%, respectively) than among controls (73%, 19%, 14%, and 2%). Independent risk factors for HIV infection were RAS without condoms (odds ratio = 4.4, p = 0.0004) and delayed application of condoms during RAS (odds ratio = 5.8, p = 0.01). There was an association with condom failure (breakage or slippage) during RAS that approached significance (odds ratio = 2.9, p = 0.09). Delayed application of condoms for RAS may result in contact with preejaculatory fluid. This behavior, which to date has received little attention, may pose as much risk for HIV infection as fully unprotected RAS.

The risks and benefits of accepting men who have had sex with men as blood donors

BACKGROUND

It has been suggested that men who have had sex with men (MSM) should become eligible to donate blood if they recently abstained from male-to-male sex.

STUDY DESIGN AND METHODS

The impact of a 12-month deferral policy for MSM on the risk of introducing contaminated units in the blood supply and the benefit of obtaining additional donations were estimated. Considered were the prevalence of HIV among MSM, the window period of infection, the rate of laboratory testing errors, and the occurrence of other system failures. This was compared with the risk and benefit that currently results from accepting female donors who have had sex with MSM.

RESULTS

The revised policy for MSM would potentially result in one HIV-contaminated unit for every 136,000 additional donations (95% CI, 1 in 69,000 to 1 in 268,000), for an overall increase in HIV risk estimated at 8 percent. The number of donations would increase by 1.3 percent (95% CI, 0.9%-1.7%). The risk-benefit ratio of currently accepting female partners of MSM is approximately five times lower.

CONCLUSION

The risk increment of accepting 12-month abstinent MSM would be very small but not zero. From a risk-benefit perspective, the current deferral policy for MSM is more efficient compared to an analogous hypothetical criterion for female partners of MSM.

Increases in HIV incidence among men who have sex with men undergoing repeat diagnostic HIV testing in Ontario, Canada

OBJECTIVE

To estimate HIV incidence density for different exposure categories among people undergoing repeat testing in Ontario, Canada.

METHODS

Persons using voluntary, diagnostic HIV testing at least twice were identified by computerized and manual record linkage. In the 1992-2000 period, 980 seroconverters and 340 994 repeat negative testers contributed 936 145 person years (PY) of observation. Incidence density (ID) was calculated according to Kitayaporn et al. Poisson regression was used to evaluate differences in incidence.

RESULTS

Among men who have sex with men (MSM), ID declined between 1992-1996, from 1.23 per 100 PY in 1992 to 0.79 per 100 PY in 1996 [relative risk (RR), 0.86 per year; 95% confidence interval (CI), 0.77-0.96]. Subsequently, ID increased to 1.39 per 100 PY in 1999 (RR, 1.18 per year; 95% CI, 1.05-1.34). In 2000, ID was 1.16 per 100 PY but this decrease was not statistically significantly different from 1999. MSM in their twenties had the highest ID in 1992-1996, but in 1996-2000 MSM in their thirties had the highest risk of infection. Among injecting drug users (IDU), ID decreased from 0.64 per 100 PY in 1992 to 0.14 per 100 PY in 2000 (RR, 0.87 per year; 95% CI, 0.80-0.94). Among heterosexuals, annual incidence remained constant at about 0.03 per 100 PY in 1992-2000.

CONCLUSIONS

Increases in ID were identified among MSM from 1996 to 1999. These findings are consistent with other research. Continued vigilance and improved surveillance are needed to better understand and control the epidemic.

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

To monitor HIV incidence we tested a cohort of men who have sex with men in Montreal for HIV every 6 months. Between 1996 and 2001, 17 out of 1244 participants seroconverted, for an HIV incidence of 0.56 per 100 person-years (py) (95% CL 0.29, 0.83). The incidence decreased over the study period, from 0.75 to 0.34 per 100 py; which was not statistically significant. An in-depth evaluation of the situation in Montreal could identify useful lessons for prevention efforts elsewhere.