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PrEP injections are safe and effective for transgender women

Hester Phillips

10 November 2023

Seven-country trial finds injectable PrEP is suitable for transgender women and other gender non-conforming people, including those on hormone replacement therapy

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Photos are used for illustrative purposes. They do not imply health status or behaviour. Credit: iStock/Luzo Reis

A trial assessing injectable PrEP for transgender women and other gender non-conforming people has found it is safe and effective, works with hormone replacement therapy, and was easier to adhere to than PrEP pills. 

What is the research about? 

The HIV Prevention Trials Network trial 083 (HPTN083) is an ongoing clinical trial happening in seven countries (Argentina, Brazil, Peru, the USA, South Africa, Thailand and Viet Nam). Participants were either given injectable PrEP (cabotegravir) or PrEP pills (tenofovir disoproxil fumarate plus emtricitabine). 

Unlike other PrEP trials, HPTN 083 set an enrolment minimum of 10% transgender women. Between 2016 to 2020, of the 4,566 people enrolled in HPTN083, 570 (12%) were transgender or gender-non conforming (70% of who were trans women). Around half (304) received oral PrEP and half (266) had PrEP injections.  

Why is this research important? 

Transgender and other gender diverse people are at high risk of HIV. Transgender women are 14 times more likely to have HIV than other adult women. 

PrEP is an effective HIV prevention method. But taking PrEP pills every day and getting prescription refills can be hard to do. PrEP-related stigma can also be a barrier, as can partner control and violence. PrEP injections provide an alternative. But their safety and effectiveness among trans people is understudied, including whether PrEP injections are affected by or affect gender affirming hormone therapy. 

What did they find out? 

HIV risk 

Almost half (47%) of transgender women in the study reported emotional abuse from partners. One third (30%) had violent partners. More than half (57%) reported childhood sexual abuse. 

The median number of sex partners in the past month was three. 

Rates of other sexually transmitted infections (STIs) were 16·25% for syphilis, 11.66% for rectal gonorrhoea and 20·61% for chlamydia. STI rates were similar to those among men who have sex with men in the trial. 

Despite these risk-factors, and others such as high rates of unemployment, around one quarter (28%) of trans people did not agree that they were at risk of HIV when asked. 

PrEP side effects and interaction with hormone replacement therapy 

Around 60% of participants used hormone therapy. In the PrEP injections group, although PrEP levels in the blood were higher among transgender women who were on hormone therapy than in those who were not, the difference in levels was not significant. This means injectable PrEP did not affect and was not affected by hormone therapy. 

PrEP effectiveness 

During the trial, nine transgender women got HIV. Seven were in the oral PrEP group and two were in the PrEP injection group. Blood testing found that none of the trans women who got HIV during the trial had been properly adhering to PrEP. 

PrEP adherence  

In the oral PrEP group, 24% of blood samples assessed indicated daily adherence to PrEP, and 34% showed moderate adherence (equivalent to four to six doses a week). Adherence to oral PrEP reduced over time. Adherence to PrEP injections was higher, with 92% having injections every eight weeks. 

What does this mean for HIV services? 

PrEP injections should be offered to trans people. Not only is injectable PrEP safe and effective for trans people, the findings relating to trans people’s HIV risks shows there is a great need for it. 

The fact that many participants reported intimate partner abuse should also be considered when designing HIV prevention programmes with and for trans people. Injectable PrEP is arguably more discreet than daily PrEP pills, so it could be a good option for any trans people who are experiencing partner control and other forms of abuse. Providing support for individuals and couples to stop intimate partner violence is also important to consider.   

The study found 25% of participants had depression and around 40% drank alcohol or used recreational drugs. Both issues should also be taken into consideration when designing an HIV prevention programme for trans people as both things are likely to increase people’s HIV risk and may affect PrEP adherence.  

The STI rates show how important it is to encourage trans people who are using PrEP to use condoms and get tested for STIs regularly. 

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