Decline in HIV prevalence among young men in the general population of Cotonou, Benin, 1998-2008

Prevalence of five treatable sexually transmitted infections among women in Lower River region of The Gambia

BACKGROUND

The prevalence of sexually transmitted infections (STIs) in sub-Saharan Africa is poorly described. We aimed to determine the prevalence of five treatable STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium, Treponema pallidum) in a sample of Gambian women from the general population.

METHODS

Archived specimens from 420 women aged 15 - 69 years living in The Gambia enrolled in a clinical trial of human papilloma virus vaccine schedules were tested in this study. Urine samples were tested for C. trachomatis, N. gonorrhoeae, T. vaginalis and M. genitalium using a commercially available, open-platform multiplex PCR kit. A fragment of the ompA gene was amplified from C. trachomatis-positive samples and sequenced. Serum samples were tested for T. pallidum using the Chembio DPP Syphilis Screen and Confirm test.

RESULTS

Overall, 41/420 (9.8%) women tested positive for at least one STI. 32 (7.6%), 9 (2.1%), 1 (0.2%), 1 (0.2%) and 0 (0.0%) tested positive for T. vaginalis, C. trachomatis, N gonorrhoeae, M. genitalium and T. pallidum, respectively. ompA gene sequence was available from five C. trachomatis infections: four were genovar D,one was genovar G and one was genovar F.

CONCLUSIONS

STIs are endemic in The Gambia. Monitoring systems should be established.

Gonorrhoea: a systematic review of prevalence reporting globally

BACKGROUND

The World Health Organization (WHO) recommends periodic gonorrhoea prevalence assessments in the general population or proxies thereof (including pregnant women, women attending family planning clinics, military recruits, and men undergoing employment physicals for example) and in population groups at increased risk, including men-who-have-sex-with-men (MSM) and sex workers.

METHOD

We evaluated reported prevalence data, including estimates from proxy general population samples to reflect the WHO recommendations. We describe the outcomes from the general population country-by-country and extend previous reviews to include MSM, sex workers, and extragenital infections.

RESULT AND CONCLUSION

In our systematic search, 2015 titles were reviewed (January 2010-April 2019) and 174 full-text publications were included. National, population-based prevalence data were identified in only four countries (the United States of America, the United Kingdom, Peru, New Caledonia) and local population-based estimates were reported in areas within five countries (China, South Africa, Brazil, Benin, and Malawi). The remaining studies identified only reported test positivity from non-probability, proxy general population samples. Due to the diversity of the reviewed studies, detailed comparison across studies was not possible. In MSM, data were identified from 64 studies in 25 countries. Rectal infection rates were generally higher than urogenital or pharyngeal infection rates, where extragenital testing was conducted. Data on sex workers were identified from 41 studies in 23 countries; rates in female sex workers were high. Current prevalence monitoring was shown to be highly suboptimal worldwide. Serial prevalence monitoring of critical epidemiological variables, and guidelines to optimize prevalence study conduct and reporting beyond antenatal settings are recommended.

Assessing the Potential Impact of Disruptions Due to COVID-19 on HIV Among Key and Lower-Risk Populations in the Largest Cities of Cameroon and Benin

BACKGROUND

The COVID-19 pandemic indirectly impacts HIV epidemiology in Central/West Africa. We estimated the potential impact of COVID-19-related disruptions to HIV prevention/treatment services and sexual partnerships on HIV incidence and HIV-related deaths among key populations including female sex workers (FSW), their clients, men who have sex with men, and overall.

SETTING

Yaoundé (Cameroon) and Cotonou (Benin).

METHODS

We used mathematical models of HIV calibrated to city population-specific and risk population-specific demographic/behavioral/epidemic data. We estimated the relative change in 1-year HIV incidence and HIV-related deaths for various disruption scenarios of HIV prevention/treatment services and decreased casual/commercial partnerships, compared with a scenario without COVID-19.

RESULTS

A 50% reduction in condom use in all partnerships over 6 months would increase 1-year HIV incidence by 39%, 42%, 31%, and 23% among men who have sex with men, FSW, clients, and overall in Yaoundé, respectively, and 69%, 49%, and 23% among FSW, clients, and overall, respectively, in Cotonou. Combining a 6-month interruption of ART initiation and 50% reduction in HIV prevention/treatment use would increase HIV incidence by 50% and HIV-related deaths by 20%. This increase in HIV infections would be halved by a simultaneous 50% reduction in casual and commercial partnerships.

CONCLUSIONS

Reductions in condom use after COVID-19 would increase infections among key populations disproportionately, particularly FSW in Cotonou, who need uninterrupted condom provision. Disruptions in HIV prevention/treatment services have the biggest impacts on HIV infections and deaths overall, only partially mitigated by equal reductions in casual/commercial sexual partnerships. Maintaining ART provision must be prioritized to minimize short-term excess HIV-related deaths.

Mathematical Model Impact Analysis of a Real-Life Pre-exposure Prophylaxis and Treatment-As-Prevention Study Among Female Sex Workers in Cotonou, Benin

BACKGROUND

Daily pre-exposure prophylaxis (PrEP) and treatment-as-prevention (TasP) reduce HIV acquisition and transmission risk, respectively. A demonstration study (2015-2017) assessed TasP and PrEP feasibility among female sex workers (FSW) in Cotonou, Benin.

SETTING

Cotonou, Benin.

METHODS

We developed a compartmental HIV transmission model featuring PrEP and antiretroviral therapy (ART) among the high-risk (FSW and clients) and low-risk populations, calibrated to historical epidemiological and demonstration study data, reflecting observed lower PrEP uptake, adherence and retention compared with TasP. We estimated the population-level impact of the 2-year study and several 20-year intervention scenarios, varying coverage and adherence independently and together. We report the percentage [median, 2.5th-97.5th percentile uncertainty interval (95% UI)] of HIV infections prevented comparing the intervention and counterfactual (2017 coverages: 0% PrEP and 49% ART) scenarios.

RESULTS

The 2-year study (2017 coverages: 9% PrEP and 83% ART) prevented an estimated 8% (95% UI 6-12) and 6% (3-10) infections among FSW over 2 and 20 years, respectively, compared with 7% (3-11) and 5% (2-9) overall. The PrEP and TasP arms prevented 0.4% (0.2-0.8) and 4.6% (2.2-8.7) infections overall over 20 years, respectively. Twenty-year PrEP and TasP scale-ups (2035 coverages: 47% PrEP and 88% ART) prevented 21% (17-26) and 17% (10-27) infections among FSW, respectively, and 5% (3-10) and 17% (10-27) overall. Compared with TasP scale-up alone, PrEP and TasP combined scale-up prevented 1.9× and 1.2× more infections among FSW and overall, respectively.

CONCLUSIONS

The demonstration study impact was modest, and mostly from TasP. Increasing PrEP adherence and coverage improves impact substantially among FSW, but little overall. We recommend TasP in prevention packages.

Data and methods to characterize the role of sex work and to inform sex work programs in generalized HIV epidemics: evidence to challenge assumptions

In the context of generalized human immunodeficiency virus (HIV) epidemics, there has been limited recent investment in HIV surveillance and prevention programming for key populations including female sex workers. Often implicit in the decision to limit investment in these epidemic settings are assumptions including that commercial sex is not significant to the sustained transmission of HIV, and HIV interventions designed to reach "all segments of society" will reach female sex workers and clients. Emerging empiric and model-based evidence is challenging these assumptions. This article highlights the frameworks and estimates used to characterize the role of sex work in HIV epidemics as well as the relevant empiric data landscape on sex work in generalized HIV epidemics and their strengths and limitations. Traditional approaches to estimate the contribution of sex work to HIV epidemics do not capture the potential for upstream and downstream sexual and vertical HIV transmission. Emerging approaches such as the transmission population attributable fraction from dynamic mathematical models can address this gap. To move forward, the HIV scientific community must begin by replacing assumptions about the epidemiology of generalized HIV epidemics with data and more appropriate methods of estimating the contribution of unprotected sex in the context of sex work.

Targeting core groups for gonorrhoea control: feasibility and impact

OBJECTIVE

We aimed to outline why core groups should be targeted in Neisseria gonorrhoeae control and suggest several important and timely interventions to target core groups while highly resistant strains are spreading.

METHODS

Core group definition, feasibility and impact of gonorrhoea core group interventions as well as gonorrhoea resistance development have been reviewed in the paper.

RESULTS

Core group interventions have proven effective in gonorrhoea control in the past but are compromised by the spread of highly resistant strains.

CONCLUSIONS

Worldwide functional Gonorrhoea Antimicrobial Surveillance Program, better screening and better treatment programmes are needed. Prevention through condom promotion aimed at core groups remains essential. More specific treatment guidance for low-income and middle-income countries without resistance data is required in the meantime to achieve a better use of antibiotics.

Positive impact of increases in condom use among female sex workers and clients in a medium HIV prevalence epidemic: modelling results from Project SIDA1/2/3 in Cotonou, Benin

BACKGROUND

A comprehensive, HIV prevention programme (Projet Sida1/2/3) was implemented among female sex workers (FSWs) in Cotonou, Benin, in 1993 following which condom use among FSWs increased threefold between 1993 and 2008 while FSW HIV prevalence declined from 53.3% to 30.4%.

OBJECTIVE

Estimate the potential impact of the intervention on HIV prevalence/incidence in FSWs, clients and the general population in Cotonou, Benin.

METHODS AND FINDINGS

A transmission dynamics model parameterised with setting-specific bio-behavioural data was used within a Bayesian framework to fit the model and simulate HIV transmission in the high and low-risk population of Cotonou and to estimate HIV incidence and infections averted by SIDA1/2/3. Our model results suggest that prior to SIDA1/2/3 commercial sex had contributed directly or indirectly to 93% (84-98%) of all cumulative infections and that the observed decline in FSWs HIV prevalence was more consistent with the self-reported post-intervention increase in condom use by FSWs than a counterfactual assuming no change in condom use after 1993 (CF-1). Compared to the counterfactual (CF-1), the increase in condom use may have prevented 62% (52-71%) of new HIV infections among FSWs between 1993 and 2008 and 33% (20-46%) in the overall population.

CONCLUSIONS

Our analysis provides plausible evidence that the post-intervention increase in condom use during commercial sex significantly reduced HIV prevalence and incidence among FSWs and general population. Sex worker interventions can be effective even in medium HIV prevalence epidemics and need to be sustained over the long-term.

Decline in the prevalence of HIV and sexually transmitted infections among female sex workers in Benin over 15 years of targeted interventions

BACKGROUND

An HIV-preventive intervention targeting the sex work milieu and involving fully integrated components of structural interventions, communication for behavioral change and care for sexually transmitted infections (STIs), was implemented in Benin by a Canadian project from 1992 to 2006. It first covered Cotonou before being extended to other main cities from 2000. At the project end, the Beninese authorities took over the intervention, but structural interventions were interrupted and other intervention components were implemented separately. We estimated time trends in HIV/STI prevalence among female sex workers (FSWs) from 1993 to 2008 and assessed the impact of the change in intervention model on trends.

METHODS

Six integrated biological and behavioral surveys were carried out among FSWs. Time trend analysis controlled for potential sociodemographic confounders using log-binomial regression.

RESULTS

In Cotonou, from 1993 to 2008, there was a significant decrease in HIV (53.3%-30.4%), gonorrhea (43.2%-6.4%), and chlamydia (9.4%-2.8%) prevalence (all adjusted P = 0.0001). The decrease in HIV and gonorrhea prevalence was also significant in the other cities between 2002 and 2008. In 2002, gonorrhea prevalence was lower in Cotonou than elsewhere (prevalence ratio = 0.53, 95% confidence interval: 0.32 to 0.88). From 2005 to 2008, there was an increase in gonorrhea prevalence (prevalence ratio = 1.76, 95% confidence interval: 1.17 to 2.65) in all cities combined.

CONCLUSIONS

Our results suggest a significant impact of this targeted preventive intervention on HIV/STI prevalence among FSWs. The recent increase in gonorrhea prevalence could be related to the lack of integration of the intervention components.