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5 years of PrEP: evolution, challenges and prospects

We've reached another stage in preventing HIV, where it will become more and more difficult to reach the ‘high hanging fruit’

We talked with Dr Thijs Reyniers, a postdoctoral researcher from the Unit of Sexual Health including HIV. He mainly works in the domain of HIV prevention and sexual health. His research is largely focused on the implementation of PrEP (Pre-Exposure Prophylaxis) in Belgium and West Africa. Thijs is involved in the PROMISE (Optimise PrEP to Maximise Impact) project. This makes him the right person to tell us more about the evolution, challenges and prospects of PrEP.

Belgium was one of the first countries to implement PrEP. What is its effect after five years?

Thijs Reyniers: This question seems  relatively easy  to answer, but currently we have no hard evidence for PrEP’s effectiveness. The number of HIV diagnoses was already declining in Belgium before PrEP was introduced. It is difficult to disentangle the efforts of treatment as prevention (TasP), HIV testing campaigns, and other combination prevention strategies like condoms and PrEP. Nevertheless, we are optimistic as we see that the number of HIV diagnoses among Belgian men who have sex with men (MSM) is declining. This group has the most interest in PrEP in Belgium.

Another difficulty is that since 2020 the sharp decline can also be partially attributed to the COVID-19 situation. From our own research we know that during the first COVID-19 lockdown MSM had far less sexual activities with non-steady partners. Moreover, our data shows that the majority of those who remained to have sex with non-steady partners were either using PrEP or indicated to be HIV positive. Knowing that many of those diagnosed with HIV have an undetectable viral load (the level of HIV in the blood) in Belgium, the risk for HIV transmission during this COVID-19 period may have been particularly low. The lower the viral load, the lower the risk of infection.

Since two years the data shows that the epidemic is getting more diverse in terms of social background and nationalities. To have a larger impact, we need to think of ways to get PrEP to those who are not yet reached, such as certain sub-populations of people with a migrant background or ethnic minorities.

Do other countries see similar effects?

Thijs Reyniers: There are some countries, or regions such as New South Wales in Australia, were the number of HIV diagnoses has decreased significantly after integrating PrEP in combination with HIV testing campaigns. ITM was also involved in a PrEP study among almost 600 West-African MSM, which resulted in a lower HIV incidence within this population. However, adherence to the medication and the retention rate were sub-optimal in this study, which is something we also see in other studies in low- and-middle-income countries.

How can you explain this?

Thijs Reyniers: In interviews and focus group discussions with West-African MSM we learned that stigma still plays an important role. For example, many of these MSM may live at home with their parents, or with female partners, making it difficult to hide a large amount of pills. Stigma associated with homosexuality, promiscuity or HIV can also operate as a barrier to adequately inform people about HIV, HIV risk and HIV prevention strategies. And for people living in precarious situations, HIV prevention is not their top priority. This demonstrates the difficulty of implementing a strategy such as PrEP, in order for it to be effective. Many countries are still in the process of implementing PrEP and we are still learning on how to best evaluate the impact of PrEP on a national scale. Together with the European Centre for Disease Prevention and Control, we are developing a standardised monitoring tool to this end.

What about condoms? Many people fear that PrEP will lead to more unprotected sex.

Thijs Reyniers: When PrEP was introduced, the message was that it needed to be integrated as an additional strategy, next to condoms. The first studies with PrEP concluded that there was no evidence that PrEP will lead to more condomless sex. Moreover, it is commonly known that condom use was already declining before PrEP was introduced. However, I think we have to be realistic and transparent about it: the introduction of PrEP is most likely leading to more condomless sex. In any case, it is not leading to more condom use.

Then, how is PrEP a good thing?

Thijs Reyniers: What is usually left out  of the discussion is the finding that PrEP users can have sex without the anxiety of acquiring HIV or without the fear of infecting others. In our studies we found that PrEP users feel that they can have more pleasurable sexual encounters,  while being properly protected against HIV. The question remains how the epidemics of other sexually transmitted infections now will evolve and how they can be dealt with.

Can vaccines help stop the spread of HIV?

Thijs Reyniers: The research on HIV vaccines is still evolving, and multiple studies are currently ongoing. But it seems that it may still take many years for such a vaccine to be ready. What is next in the development pipeline is ‘long-acting PrEP’. For example, there are very good results for ‘injectable PrEP’ which is injected every eight weeks, and in the long run maybe a once-a-month pill or implants. Although it is not a vaccine, this is already a step in the right direction. The US Food and Drug Administration (FDA)  recently approved such injectable PrEP for HIV prevention on 21 December. This is a really big move forward.

That sounds hopeful, so this could mean the end of HIV?

Thijs Reyniers: Such long-acting PrEP modalities can be very promising, especially in low- and-middle income countries where we see that people can have more difficulties with adhering to oral PrEP. In my opinion, we need to make sure that these long-acting PrEP options will not be used as replacement for oral PrEP. We have come a long way and the number of HIV diagnoses is declining. But now we have reached another stage in preventing HIV, where it will become more and more difficult to reach the ‘high hanging fruit’. Novel PrEP modalities are undoubtedly welcome, but much more is needed to eradicate HIV. In short, I’m positive, but the battle is not over yet.

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