While PrEP users in Brazil and Mexico had few new HIV infections, there were a high number of infections among users in Peru. The data is from the ImPrEP project in Latin America and was presented this week at the 11th International AIDS Conference on HIV Science (IAS 2021), which is being held online.
The HIV epidemic in the region is concentrated in vulnerable populations, primarily affecting men who have sex with men (MSM) and transgender women. Although the prevalence is estimated at about 10% in these groups, the incidence of new infections in Brazil and Peru is estimated at 5% and 3.5%, respectively, with no decrease in new infections observed in the past decade.
The ImPrEP study has been conducted in Brazil (14 sites in 12 cities), Peru (10 sites in 6 cities) and Mexico (10 sites in 6 cities) since 2018. Although the main objective is to monitor the uptake, adherence and impact of HIV Incidence rate among men who have sex with men and transgender women Additional analyzes looked at factors indicating who would become infected with HIV during the study (seroconversion) and barriers to accessing PrEP. The emerging findings contribute to a better understanding of the factors that enable successful PrEP uptake and adherence in these countries, and those that hinder adoption of a highly effective HIV prevention tool.
All participants received 30-day PrEP therapy and returned a month later for a safety visit. Subsequent visits (including renewal of prescriptions, HIV testing and behavioral assessments) were conducted on a quarterly basis. Adherence was measured by the drug ownership rate – the number of tablets prescribed divided by the days between visits, with a lower rate indicating lower adherence.
Professor Carlos Caceres of the University of Peru Cayetano Heredia in Lima presented the findings regarding seroconversions during the EMPREP study.
A total of 10,410 participants had been recruited by April 2021: 4,165 in Brazil, 3,360 in Mexico and 2,885 in Peru. Of these, 84 acquired HIV (overall incidence rate 0.75%, 95% confidence interval 0.61–0.93). Incidence was low in Brazil (0.31%) and Mexico (0.44%). Approximately two-thirds of infections occurred in Peru, where the incidence was 2.42% (95% CI 1.85–3.18). All participants who tested positive for HIV were removed from the cohort and linked to HIV care.
The analysis revealed strong predictors of HIV acquisition: Peruvians and any participant aged 18 to 24 had nearly four times the risk of seroconversion, while those with lower adherence (drug ownership rate less than 0.53) had three. fold, and those engaging in receptive anal sex without a condom were twice as likely to do so.
Transgender women had no greater risk of seroconversion than men who have sex with men. No associations were found between a history of STDs or being a sex worker and seroconversion.
Caceres cited some possible reasons for the high number of HIV infections in Peru, such as a higher proportion of young participants, more transgender women, lower education levels, lower adherence to PrEP, and fewer people specifically seeking PrEP. He also stated that public clinics for sexually transmitted diseases in Peru tend to serve low-income sex workers and women who have sex with men and transgender women, compared to units in Brazil and Mexico, which tend to serve a wider range of the population.
“PrEP implementation should pay more direct attention to early indicators of program failure and provide additional support to those who may encounter such failures,” Caceres concluded.
Barriers to PrEP adherence among Peruvian participants
A qualitative substudy, led by Dr. Jean-Pierre Jeron Sousa of the Peruvian ImPrEP team, investigated the barriers and challenges to PrEP adherence, examining reasons for discontinuation in interviews with 10 MSM and four transgender women in three locations in Peru.
Those who stop PrEP treatment tend to have multiple sexual partners and a lower risk of HIV infection. Many of these participants engaged in sex work. As Caceres mentioned, these participants did not intentionally seek PrEP treatment, but rather when they went to STD clinics to get tested or get condoms. While some feel that PrEP gives them the ability to have sex without a condom, in general they show a clear preference for condoms, based on the protection they get from HIV and STDs in only one way. This was despite reports of sporadic condom use.
Difficulties with PrEP have included the challenges of maintaining a daily regimen, using combined methods of preventing and overcoming side effects. PrEP use has been described as situational, based on specific sexual partners and whether sex is considered risky.
Participants also cited social barriers such as disclosure of PrEP use to family, friends, and partners; stigma related to PrEP (due to confusion between PrEP and ART); issues related to gender identity; The stigma associated with HIV.
Health providers can play an important role in supporting adherence. Participants reported that they were more satisfied with their interaction with healthcare professionals, but some doubts and mistrust were reported, especially regarding the efficacy of PrEP in preventing HIV infection.
Participants highlighted limited capacity in health facilities as a structural barrier, particularly with regard to the provision of personalized PrEP services. There was also concern about potential breaches of confidentiality as this could lead to discrimination based on sexual orientation and gender identity – a particular concern of transgender women interviewed.
What about event-based PrEP?
A poster presentation by Dr. Brenda Hoagland of the Oswaldo Cruz Foundation showed the results of an event-based sub-study on PrEP. One possible way to overcome—or at least reduce—adherence difficulties associated with PrEP is by using event-based PrEP: one pill taken 2 to 24 hours before sex, one 24 hours after the first dose, and another 48 hours after.
However, there was little awareness of this approach among 3,764 MSM and transgender women in the three countries, with women in Mexico being slightly more aware (36%) than those in Brazil (30%) and Peru (28%). ). This subsample consisted largely of MSM (98%), with a mean age of 31. Daily use of PrEP was reported by 97% of the sample, while having sex less than twice a week was reported. About a quarter.
After a brief explanation of the event-based PrEP, 27% of Mexican participants, 26% of Peruvian participants, and 20% of Brazilians reported being interested in moving to it. Among the unconcerned, comfort with daily PrEP (98%), concerns about the difficulty of the event-based regimen (93%), and concern about HIV risk (91%) were cited as the main reasons.
Participants who had sex less than twice a week were more interested in event-based PrEP. Important reasons to be interested in changing include: I know very well when to have sex; I have a low risk of getting HIV without daily PrEP and once a day PrEP seems to be very harmful to my body.
The authors concluded by emphasizing a positive conclusion that those eligible for event-oriented PrEP (based on non-recurrent gender) demonstrated interest and found it appropriate. However, “beliefs about low efficacy and concern about HIV risk suggest that dissemination of knowledge is necessary to increase interest in event-based preventive therapy.”
Source: Aid map
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