Estimating the contribution of key populations towards spread of HIV in Dakar, Senegal
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Introduction
Key populations including female sex workers (FSW) and men who have sex with men (MSM) bear a disproportionate burden of HIV. However, the role of focusing prevention efforts on these groups for reducing a country’s HIV epidemic is debated. We estimate the extent to which HIV transmission amongst FSW and MSM contributes to overall HIV transmission in Dakar, Senegal, using a dynamic assessment of the population attributable fraction (PAF).
Methods
A dynamic transmission model of HIV among FSW, their clients, MSM and the lower-risk adult population was parameterized and calibrated within a Bayesian framework using setting-specific demographic, behavioural, HIV epidemiological, and antiretroviral treatment (ART) coverage data for 1985-2015. We used the model to estimate the 10-year PAF of commercial sex between FSW and their clients, and sex between men, to overall HIV transmission (defined as the percentage of new infections prevented when these modes of transmission are removed). Additionally, we estimated the prevention benefits associated with historical increases in condom use and ART uptake, and impact of further increases in prevention and treatment.
Results
The model projections suggest that unprotected sex between men contributed to 42% (2.5 to 97.5th percentile range 24-59%) of transmissions between 1995-2005, increasing to 64% (37-79%) from 2015-2025. The 10-year PAF of commercial sex is smaller, diminishing from 21% (7-39%) in 1995 to 14% (5-35%) in 2015. Without ART, 49% (32-71%) more HIV infections would have occurred since 2000, when ART was initiated, whereas without condom use since 1985, 67% (27-179%) more HIV infections would have occurred, and the overall HIV prevalence would have been 60% (29-211%) greater than what it is now. Further large decreases in HIV incidence (68%) can be achieved by scaling up ART in MSM to 74% coverage and reducing their susceptibility to HIV by a two-thirds through any prevention modality.
Conclusions
Unprotected sex between men may be an important contributor to HIV transmission in Dakar, due to suboptimal coverage of evidence-based interventions. Although existing interventions have effectively reduced HIV transmission amongst adults, it is crucial that further strategies address the unmet need amongst MSM.
Key populations including female sex workers (FSW) and men who have sex with men (MSM) bear a disproportionate burden of HIV. However, the role of focusing prevention efforts on these groups for reducing a country’s HIV epidemic is debated. We estimate the extent to which HIV transmission amongst FSW and MSM contributes to overall HIV transmission in Dakar, Senegal, using a dynamic assessment of the population attributable fraction (PAF).
Methods
A dynamic transmission model of HIV among FSW, their clients, MSM and the lower-risk adult population was parameterized and calibrated within a Bayesian framework using setting-specific demographic, behavioural, HIV epidemiological, and antiretroviral treatment (ART) coverage data for 1985-2015. We used the model to estimate the 10-year PAF of commercial sex between FSW and their clients, and sex between men, to overall HIV transmission (defined as the percentage of new infections prevented when these modes of transmission are removed). Additionally, we estimated the prevention benefits associated with historical increases in condom use and ART uptake, and impact of further increases in prevention and treatment.
Results
The model projections suggest that unprotected sex between men contributed to 42% (2.5 to 97.5th percentile range 24-59%) of transmissions between 1995-2005, increasing to 64% (37-79%) from 2015-2025. The 10-year PAF of commercial sex is smaller, diminishing from 21% (7-39%) in 1995 to 14% (5-35%) in 2015. Without ART, 49% (32-71%) more HIV infections would have occurred since 2000, when ART was initiated, whereas without condom use since 1985, 67% (27-179%) more HIV infections would have occurred, and the overall HIV prevalence would have been 60% (29-211%) greater than what it is now. Further large decreases in HIV incidence (68%) can be achieved by scaling up ART in MSM to 74% coverage and reducing their susceptibility to HIV by a two-thirds through any prevention modality.
Conclusions
Unprotected sex between men may be an important contributor to HIV transmission in Dakar, due to suboptimal coverage of evidence-based interventions. Although existing interventions have effectively reduced HIV transmission amongst adults, it is crucial that further strategies address the unmet need amongst MSM.
Date Issued
2018-07-01
Date Acceptance
2018-05-16
Citation
Journal of the International AIDS Society, 2018, 21 (S5)
ISSN
1758-2652
Publisher
International AIDS Society
Journal / Book Title
Journal of the International AIDS Society
Volume
21
Issue
S5
Copyright Statement
© 2018 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Sponsor
National Institutes of Health
USAID
Medical Research Council (MRC)
Grant Number
P30AI094189 Sub#2002569335
PO: 2003388501
MR/R015600/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Immunology
Infectious Diseases
population attributable fraction
HIV
female sex workers
men who have sex with men
clients
condom use
keypopulations
FEMALE SEX WORKERS
SEXUALLY-TRANSMITTED INFECTIONS
MIDDLE-INCOME COUNTRIES
PREEXPOSURE PROPHYLAXIS
POTENTIAL IMPACT
GLOBAL EPIDEMIOLOGY
RISK BEHAVIORS
COMMERCIAL SEX
MEN
PREVALENCE
HIV
clients
condom use
female sex workers
key populations
men who have sex with men
population attributable fraction
1199 Other Medical and Health Sciences
Publication Status
Published
Article Number
e25126
Date Publish Online
2018-07-22