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Is PrEP Needed for MSM in West Africa? HIV Incidence in a Prospective Multicountry Cohort

2017; Lippincott Williams & Wilkins; Volume: 75; Issue: 3 Linguagem: Inglês

10.1097/qai.0000000000001288

1944-7884

Clotilde Couderc, Bintou Dembélé Keïta, Camille Anoma, Abdoulaye Wade, Alou Coulibaly, Sylvain Ehouman, Abdou Diop, Yves Yomb, Émilie Henry, Bruno Spire, Christian Laurent,

Sex work and related issues

To the Editors: INTRODUCTION Results from clinical trials highlighting the effectiveness of pre-exposure prophylaxis (PrEP) in preventing HIV infection in men who have sex with men (MSM)1–3 have led to the endorsement of many calls and recommendations to scale up access to this new tool. Since September 2015, the World Health Organization (WHO) has recommended to offer PrEP as part of a comprehensive HIV prevention package for people at substantial risk of HIV infection (ie, incidence greater than 3 per 100 person-years in the absence of PrEP).4 West African countries have mixed HIV epidemics, with a relatively low prevalence in the general population (1%–3%) but a high prevalence in key populations such as MSM (15%–20%).5–9 Recent data suggest that infection in MSM may account for a significant proportion of all new HIV infections in this region.10 Despite an improvement in recent years in some parts of West Africa, MSM often have poor access to prevention, care, and treatment because of stigmatization and condemnation of same-sex relationships. A limited number of MSM-friendly clinics only provide targeted HIV services. PrEP for MSM is not yet routinely available. Estimating HIV incidence data in MSM living in West Africa would be useful to guide the national public health recommendations. As part of a pilot study designed to assess the feasibility of implementing a larger prospective cohort study in this key population (CohMSM ANRS 12280), we estimated the incidence of HIV infection in MSM in 3 West African countries. Here, we report our findings and assess the need for PrEP for this population using the WHO-recommended incidence threshold. METHODS A prospective cohort pilot study was performed from July 2013 to October 2015 in Bamako (Mali), Abidjan (Côte d'Ivoire), and Dakar (Senegal). MSM were enrolled and followed up by leading organizations in the fight against HIV infection and in providing MSM-specific prevention, care, and support. In Bamako, the study was performed at Clinique des Halles, a community-based night clinic run by the association ARCAD-SIDA (Association de Recherche de Communication et d'Accompagnement à Domicile de personnes Vivant avec le VIH). This clinic provides sexual health care to MSM and sex workers.11 In Abidjan, it was performed at Clinique de Confiance, a community-based clinic, which initially provided health care to female sex workers (from 1992), then to male sex workers (from 2002), and now also to the MSM community (from 2009).12 In Dakar, the study was performed at the Institut d'Hygiène Sociale public clinic, which participated in the first epidemiological surveys among MSM in Africa.13,14 All 3 clinics routinely provided targeted counseling and support, HIV testing, clinical examinations, diagnosis and treatment for sexually transmitted infections, condoms and lubricants, and HIV care including antiretroviral treatment. PrEP was not available. HIV-negative MSM did not benefit from regular follow-up, but could attend the clinics at their discretion. Only Senegalese law criminalizes same-sex relationships; but, social rejection of homosexuality is common in all 3 countries. The study protocol was reviewed and approved by the National Ethics Committees of Mali, Côte d'Ivoire, and Senegal. Participants provided their written consent to participate. MSM were informed about the study when they attended the clinics, or outside the clinics by peer leaders involved in the routine activities of these clinics. The enrollment of MSM was performed from July 2013 to November 2013 in Bamako, from September 2013 to April 2015 in Abidjan, and from September 2013 to December 2013 in Dakar. All MSM attending the study clinics were supposed to be assessed for eligibility (except those known to be infected with HIV). However, the recruitment was sometimes suspended because of the high clinic workload and lack of human and financial resources in this pilot study. MSM eligibility criteria were as follows: aged 18 years or older, HIV negative (status confirmed at study enrollment), and reporting at least 1 episode of anal intercourse with another man within the previous 3 months. Two follow-up visits (3 and 6 months after enrollment, respectively) were offered to each participant. Enrollment and follow-up visits included HIV testing along with pre- and post-test counseling, and condoms and lubricants. If necessary, diagnosis and treatment for sexually transmitted infection were provided. All services were free of charge. Participants were compensated a maximum of US$5 for transport costs for follow-up visits in the community-based clinics in Bamako and Abidjan, but not in the public clinic in Dakar. Participants did not receive any other compensation. In case of HIV diagnosis, medical services were proposed to the participant under the clinic's usual financial conditions. Only the date of birth and the dates and results of HIV testing were collected for each participant. HIV testing was performed according to national algorithms. All 3 clinics first used the Determine HIV 1/2 test (Abbott Laboratories). Positive or indeterminate results were confirmed using the ImmunoComb II HIV 1&2 test (Alere) in Bamako and Dakar, or the Bioline HIV 1/2 3.0 test (Standard Diagnostics) in Abidjan. HIV seroconversion was estimated to have occurred at the midtime between the last negative test and the first positive one. Cox proportional hazard models were used to compare the risk of seroconversion between the study sites. Analyses were performed using Stata software (version 13; StataCorp., College Station, TX). RESULTS Of 375 MSM tested for HIV at baseline, 324 MSM were HIV negative. Of the latter, 295 (91.0%) MSM had at least 1 HIV test during follow-up and were included in the present analysis: 168 (100%) MSM in Bamako, 73 (71.6%) MSM in Abidjan, and 54 (100%) MSM in Dakar (Table 1). Of these, 265 (89.8%) MSM had 2 HIV tests during follow-up: 161 (95.8%) MSM in Bamako, 50 (68.5%) MSM in Abidjan, and 54 (100%) MSM in Dakar. The overall median age was 23.6 years [interquartile range (IQR) 20.8–27.6 years]. During follow-up, HIV testing was performed after an overall median time from enrollment of 3.2 months (IQR 3.0–3.5 months) and 6.3 months (IQR 6.0–6.6 months), respectively. The IQRs of clinic-specific data showed that a higher number of participants in Abidjan did not respect the testing schedule. Only 1 MSM in Bamako attended the clinic for a follow-up visit, but was not tested for HIV. He was tested at the second follow-up visit, and the result was negative. The total follow-up time was 160.1 person-years, during which 8 MSM had HIV seroconverted (7 in Abidjan and 1 in Bamako).TABLE 1.: Characteristics of MSM and HIV Incidence Rates in Bamako, Abidjan, and Dakar in 2013–2015The HIV incidence rate was 5.0 [95% confidence interval (CI) 2.5 to 10.0] per 100 person-years overall, with large discrepancies between the study sites: 1.1 (95% CI: 0.2 to 8.0) per 100 person-years in Bamako and 15.9 (95% CI: 7.6 to 33.4) per 100 person-years in Abidjan. A Cox univariate analysis showed that the risk of HIV seroconversion was significantly higher in Abidjan than in Bamako [hazard ratio (HR) 17.9, 95% CI: 2.2 to 145.7, P = 0.007]. Adjustment for age did not substantially modify the result (adjusted HR 20.0, 95% CI: 2.3 to 173.2; P = 0.007). By contrast, HIV seroconversion was not associated with age: compared with the 18–21-year category, adjusted HR was 0.3 (95% CI: 0.0 to 3.2; P = 0.3) for 22–24-year olds, 0.7 (95% CI: 0.1 to 4.7; P = 0.8) for 25–28-year olds, and 0.5 (95% CI: 0.1 to 3.9; P = 0.5) for those >28 years old. DISCUSSION This pilot study showed that HIV incidence rate is very high in some MSM populations in West Africa. In Abidjan, where the HIV incidence rate was by far the highest, the MSM follow-up was also worse than that in Bamako and Dakar, with lower proportions of MSM returning to the clinic for the first and the second follow-up HIV tests, and higher proportion of participants not respecting the testing schedule. These data suggest that different populations might have been enrolled in the 3 different clinics. For instance, a higher proportion of participants in Abidjan may have been sex workers than in the other 2 cities, given that the local clinic has been dedicated to this population for many years.12 Indeed, male sex workers are more vulnerable to HIV infection and more mobile (which hinders follow-up) than other MSM. Unfortunately, data were not available in this pilot study to confirm this hypothesis. Our findings add important data to the limited body of knowledge regarding HIV incidence in MSM in sub-Saharan Africa. In Kenya, among MSM included in a prospective cohort study in Nairobi and Mombasa from 2005 to 2008, the HIV incidence rate was 6.8 (95% CI: 4.9 to 9.2) per 100 person-years.15 Another prospective cohort study of MSM followed up in 2 clinics in coastal Kenya reported an HIV incidence of 8.6 (95% CI: 6.7 to 11.0) per 100 person-years over the period 2005–2011.16 In Senegal, the HIV incidence rate was 16.0 (95% CI: 4.6 to 27.4) per 100 person-years in a small sample of 40 MSM who had had 2 HIV tests 15 months apart in 2011–2012.17 These data greatly contrast with the absence of seroconversion observed in our Senegalese participants. In Togo, a modeling study based on limited available local data estimated that the HIV incidence rate was 2.8 per 100 person-years among MSM in 2013.18 The main strength of our study was that the HIV incidence rate was estimated in a prospective cohort study with quarterly testing. In addition, a high proportion of MSM had both HIV follow-up tests scheduled in the study protocol. However, our findings should be interpreted taking into account the following limitations. First, as with other studies in this hard-to-reach population,16,17 our study was performed on a convenience sample of MSM attending MSM-friendly clinics either spontaneously or after being informed about the study by peer leaders. Accordingly, these MSM might not be fully representative of the global MSM community in the 3 countries investigated, and therefore our estimations of HIV incidence might not exactly reflect those of the global community. However, our data showed that at least some subgroups of MSM have high incidence rates and need additional HIV prevention services. Second, the proportion of eligible MSM who agreed to participate in the study was not available. Nevertheless, local investigators noted few refusals to participate. Third, the number of MSM enrolled in each city and the follow-up time of this pilot study were rather low. Our punctual estimations should therefore be interpreted along with their CIs. HIV incidence would probably decrease with longer follow-up because people most at risk are likely to be infected earlier than those less at risk. Finally, this pilot study recorded very few data, which limits the possibility of accurately characterizing the study population, and limits analysis and interpretation of estimations. According to the WHO-recommended incidence criteria, the HIV incidence rates estimated in our study and other studies suggest that at least some MSM living in West Africa need PrEP. Although data on HIV incidence and risk factors from larger cohort studies would be useful, PrEP should be added to national AIDS programs as a complementary prevention tool for MSM most at risk of HIV infection. The high overall follow-up recorded in this pilot study is encouraging for PrEP implementation, as MSM commitment will be crucial to efficiently deliver PrEP. However, our findings in Côte d'Ivoire show that the follow-up of MSM on PrEP will require special attention. Operational research is imperative in this context to guide the implementation of PrEP within a comprehensive HIV prevention package targeted at MSM.