Changing risk behaviours and the HIV epidemic: a mathematical analysis in the context of treatment as prevention

Feasibility and Acceptability of HIV Self-Test Kit Distribution Through PrEP Clients' Social and Sexual Networks to Increase HIV Testing and PrEP Information

OBJECTIVE

To determine the feasibility, acceptability, and implementation of a HIV self-test (HIVST) program through PrEP clients' social and sexual networks.

BACKGROUND

HIV testing is critical for treatment and prevention engagement. HIVST kits can overcome barriers to testing. A negative result is an opportunity to provide PrEP information. We describe implementation factors associated with engaging current Mobile PrEP (MP) clients to distribute HIVST kits and PrEP information through their networks.

SETTING

Community venues in Miami-Dade County, Florida.

METHODS

A baseline survey collected network information and explored distribution plans for offering HIVST kits. A follow-up survey evaluated use and distribution. A logic model describes the process of implementation and evaluation. Up to 4 Ora-Quick HIV ST kits were offered to 81 MP clients. A brief training included resources for posttest engagement.

RESULTS

Forty-four percent of the kits were reported as distributed. Of 81 MP clients offered kits, 50 (62%) accepted. In a follow-up survey, 77% of MP clients distributed at least 1 kit. Fifty-six (86%) social network members were Latino, and 9 (14%) were Black. Three of 4 MP clients engaged in PrEP discussions (77%) with SN members. Reported reasons for HIVST kit use included convenience, confidentiality, privacy concerns, and discomfort with going to a testing site. MP clients reported that kit distribution was affected by the COVID-19 pandemic.

CONCLUSION

HIV ST kits allowed PrEP users to engage others in their social and sexual networks for HIV testing and information regarding PrEP. Work to scale-up this intervention is underway.

Condom use in combination with ART can reduce HIV incidence and mortality of PLWHA among MSM: a study from Beijing, China

BACKGROUND

Condom use and antiretroviral therapy (ART) are effective means to prevent and control HIV transmission. We aimed to assess the effect of condom use in combination with antiretroviral therapy (ART) on HIV incidence and mortality among men who had sex with men (MSM) in Beijing, China.

METHODS

We evaluated the effect of condom use, ART, and the combination of both among people living with HIV/AIDS (PLWHA) of MSM in the Chaoyang District of Beijing using the Asian Epidemic Model (AEM). Evaluation indicators included absolute risk reduction (ARR) and the percentage of relative risk reduction (RRR %).

RESULTS

HIV incidence and prevalence declined substantially when condoms were used by MSM in Chaoyang from 2003 to 2013. The ARR of HIV incidence was from 0 to 0.91% and the RRR% was from 0 to 43.93%. The ARR of HIV prevalence was from 0 to 3.79% and the RRR% was from 0 to 31.53%. The HIV mortality rate decreased substantially (ARR from 0 to 1.75%, and RRR% from 0 to 40.03%) when ART was implemented. When condom use combined with ART was implemented in MSM in 2003-2013, HIV incidence declined substantially (ARR from 0 to 0.99%, and RRR% from 0 to 46.11%). HIV prevalence was also reduced with an ARR from 0 to 3.5%, and an RRR% from 0 to 29.88%. The HIV mortality also declined substantially (ARR from - 0.01% to 1.02%, RRR% from - 1.44% to 39.98%).

CONCLUSIONS

Among MSM, a combination of condom use and ART reduces both HIV incidence and mortality caused by HIV. Combining these methods results in a more effective prevention and control of HIV.

Does size really matter? A sensitivity analysis of number of seeds in a respondent-driven sampling study of gay, bisexual and other men who have sex with men in Vancouver, Canada

Background

Respondent-driven sampling (RDS) is an increasingly used peer chain-recruitment method to sample “hard-to-reach” populations for whom there are no reliable sampling frames. Implementation success of RDS varies; one potential negative factor being the number of seeds used.

Methods

We conducted a sensitivity analysis on estimates produced using data from an RDS study of gay, bisexual and other men who have sex with men (GBMSM) aged ≥16 years living in Vancouver, Canada. Participants completed a questionnaire on demographics, sexual behavior and substance use. For analysis, we used increasing seed exclusion criteria, starting with all participants and subsequently removing unproductive seeds, chains of ≤1 recruitment waves, and chains of ≤2 recruitment waves. We calculated estimates for three different outcomes (HIV serostatus, condomless anal intercourse with HIV discordant/unknown status partner, and injecting drugs) using three different RDS weighting procedures: RDS-I, RDS-II, and RDS-SS. We also assessed seed dependence with bottleneck analyses and convergence plots. Statistical differences between RDS estimators were assessed through simulation analysis.

Results

Overall, 719 participants were recruited, which included 119 seeds and a maximum of 16 recruitment waves (mean chain length = 1.7). The sample of >0 recruitment waves removed unproductive seeds (n = 50/119, 42.0%), resulting in 69 chains (mean length = 3.0). The sample of >1 recruitment waves removed 125 seeds or recruits (17.4% of overall sample), resulting in 37 chains (mean length = 4.8). The final sample of >2 recruitment waves removed a further 182 seeds or recruits (25.3% of overall sample), resulting in 25 chains (mean length = 6.1). Convergence plots and bottleneck analyses of condomless anal intercourse with HIV discordant/unknown status partner and injecting drugs outcomes were satisfactory. For these two outcomes, regardless of seed exclusion criteria used, the crude proportions fell within 95% confidence intervals of all RDS-weighted estimates. Significant differences between the three RDS estimators were not observed.

Conclusions

Within a sample of GBMSM in Vancouver, Canada, this RDS study suggests that when equilibrium and homophily are met, although potentially costly and time consuming, analysis is not negatively affected by large numbers of unproductive or lowly productive seeds.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-016-0258-4) contains supplementary material, which is available to authorized users.

Sexual behavior, risk perception, and HIV transmission can respond to HIV antiviral drugs and vaccines through multiple pathways

There has been growing use of highly active antiretroviral treatment (HAART) for HIV and significant progress in developing prophylactic HIV vaccines. The simplest theories of counterproductive behavioral responses to such interventions tend to focus on single feedback mechanisms: for instance, HAART optimism makes infection less scary and thus promotes risky sexual behavior. Here, we develop an agent based, age-structured model of HIV transmission, risk perception, and partner selection in a core group to explore behavioral responses to interventions. We find that interventions can activate not one, but several feedback mechanisms that could potentially influence decision-making and HIV prevalence. In the model, HAART increases the attractiveness of unprotected sex, but it also increases perceived risk of infection and, on longer timescales, causes demographic impacts that partially counteract HAART optimism. Both HAART and vaccination usually lead to lower rates of unprotected sex on the whole, but intervention effectiveness depends strongly on whether individuals over- or under-estimate intervention coverage. Age-specific effects cause sexual behavior and HIV prevalence to change in opposite ways in old and young age groups. For complex infections like HIV-where interventions influence transmission, demography, sexual behavior and risk perception-we conclude that evaluations of behavioral responses should consider multiple feedback mechanisms.

Antiretroviral therapy for prevention of HIV transmission: implications for Europe

The aim of this review is to summarise the evidence on the population-level effect of antiretroviral therapy (ART) in preventing HIV infections, and to discuss potential implications in the European context of recommending starting ART when the CD4 count is above 350 cells/mm3. The ability of ART to reduce the risk of HIV transmission has been reported in observational studies and in a randomised controlled trial (HPTN 052), in which ART initiation reduced HIV transmission by 96% within serodiscordant couples. As yet, there is no direct evidence for such an effect among men having sex with men or people who inject drugs. HPTN 052 led international organisations to develop recommendations with a higher CD4 threshold for ART initiation. However, there remains a lack of strong evidence of clinical benefit for HIV-positive individuals starting ART with CD4 count above 350 cells/mm3. The main goal of ART provision should be to increase ART coverage for all those in need, based on the current guidelines, and the offer of ART to those who wish to reduce infectivity; increased HIV testing is therefore a key requirement. Other proven prevention means such as condom use and harm reduction for people who inject drugs remain critical.