HIV: there is room to improve the criteria used for prescribing PrEP

  • Date 01 December 2020
  • Category Cohorts

A study by the Instituto de Saúde Pública da Universidade do Porto (ISPUP) highlights the importance of rethinking the eligibility criteria defined for prescribing pre-exposure prophylaxis (PrEP) – a form of pharmacological prevention of the Human Immunodeficiency Virus (HIV) for individuals most at risk.

The investigation followed a group of men who have sex with men without HIV and found differences in the number of new HIV cases, according to the eligibility criteria for PrEP, using four different guidelines. The authors defend the adoption of a prescription strategy that contemplates not only objective risk criteria for contracting the infection, but also the preferences and needs of individuals, such as anticipating changes in sexual life that result in the practice of less safe sex.

PrEP is indicated for people who do not have HIV but are at greater risk of contracting it.

Co-paid by the Portuguese National Health Service (PNHS) since 2018, PrEP currently exists as a pill and has been shown to be effective in reducing HIV, especially when there is good adherence in taking it. Its prescription is written by a doctor who assesses an individual’s risk of acquiring HIV infection as well as other sexually transmitted infections.

According to Paula Meireles, the first author of the study, published in the journal Eurosurveillance, and coordinated by Henrique Barros, “there are guidelines from national and international entities that help clinicians identify who is most at risk of contracting HIV, and therefore being eligible to take PrEP”.

The existing guidelines include risk factors, associated with behaviors leading to the acquisition of the infection, such as, for example, not using a condom consistently, having sex with HIV positive people with the viral load not suppressed or having a recent sexually transmitted infection.

But there is no uniformity in these criteria. There are guidelines that include, for example, a greater number of risk factors. In practice, the same person can be classified differently according to the criteria of the guideline used.

In an article previously published in the journal Sexuality Research and Social Policy, ISPUP researchers showed that the proportion of men who have sex with men, considered eligible for PrEP, varies depending on the criteria used. The study took into account the eligibility criteria of the World Health Organization (WHO), the United States Public Health Service and Centers for Disease Control and Prevention (US-CDC), the European AIDS Clinical Society (EACS) and the PNHS.

In the study, the authors analyzed the ability of the WHO, US-CDC, EACS and PNHS eligibility criteria to predict the risk of contracting infection in a sample of men who have sex with men without HIV.

“We wanted to know if being eligible to take PrEP, according to the guidelines of these four entities, was associated with a greater probability of acquiring the infection over time”, says Paula Meireles.

The sample

Over 1200 participants without HIV of the Lisbon Cohort of Men who have Sex with Men (Lisbon MSM Cohort) were evaluated. The Lisbon MSM Cohort is a Portuguese longitudinal study, which began in 2011 and follows men who have sex with men, who get tested for HIV at the CheckpointLX, a community-based center in Lisbon.

The authors used data from the cohort participants, who performed the first assessment and were followed between 2014 and 2018. Information was collected on the sexual behavior of the participants, the type of partners and sexual relations practiced, the serological status of the sexual partners, the use of antiretrovirals and viral load, the use of condoms, the consumption of psychoactive substances, the existence of sexually transmitted infections, and the history of pre- and post-exposure prophylaxis.

Based on the information obtained and the eligibility criteria of the four entities mentioned, men were classified as eligible or not eligible for PrEP. Then, the authors analyzed whether being classified as eligible, according to the guidelines, was associated with a higher incidence of HIV over time.

HIV incidence is higher among men who are eligible for PrEP

And, it turned out that it was. “We realized that, in fact, being considered eligible for taking this prevention tool was associated with a higher incidence of HIV”, mentions the ISPUP researcher.

Of the 1254 participants in the study, 28 acquired the infection. The guidelines of the four entities analyzed were able to predict a high number of seroconversions in the sample, but there were differences between them.

The criteria that best identified men who were most at risk of contracting HIV were those of the PNHS. The Portuguese guidelines identified 85.7% of the seroconversions that occurred, which reveals that the guidelines defined by the PNHS for the acquisition of PrEP are more sensitive compared to the others.

There is room for improvement

But there is room for improvement. The study found that individuals who had initially been classified as not eligible for PrEP could account for nearly 40% of those who acquired HIV. According to the guidelines, it was understood that they would not be at risk of contracting the infection and, therefore, they would not have been prescribed PrEP.

To prevent people who need PrEP from being deprived of it, it would be important to include other factors in the guidelines. For example, “inconsistent condom use with partners with unknown HIV status was only included in the Portuguese guidelines, while psychosocial or population-level factors are often absent”, points out Paula Meireles.

Assessing the need for prescription

In order to impede new HIV infections, it would be advisable to move from a strategy that is merely based on risk assessment (past and current), in which whether the individual meets the eligibility criteria or not is analysed, to assessing his preferences and needs, within a logic of early risk management (current and future).

“If we focus on a PrEP prescription strategy that merely addresses the eligibility criteria, there is a high likelihood of losing people. Especially because there are individuals who have behaviors that do not exactly fit a certain criterion and there are also people who, at a given moment, are not considered eligible, because they do not have risky behavior, but they may in the future”, she considers.

It is therefore understood that the decision to prescribe PrEP must be shared between the doctor and the person who wants to adhere to it, and that the guidelines must also consider this aspect.

For the researcher, “if an individual understands that taking a pill, which depends on you and does not require negotiation with your partner, fits into your prevention strategy, doctors should not miss this opportunity to prescribe it. We think that the prescription decision should be shared and better suited to the needs, preferences and context of life of those who will use the tool”.

Public Health Message

The authors emphasize that PrEP is a reimbursement prevention tool that works, and although it is not intended for everyone, it can be suitable for a specific group of individuals. Therefore, it is one more tool that is available to stop HIV infections and to stop transmission.

The article entitled Different guidelines for pre-exposure prophylaxis (PrEP) eligibility estimate HIV risk differently: an incidence study in a cohort of HIV-negative men who have sex with men, Portugal, 2014-2018. is available HERE. The researchers Michael Plankey, Miguel Rocha, João Brito and Luís Mendão also participated in the study.

Image: Pexels/Anna Shvets

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