HIV News from NAM aidsmap

The implant that could offer once a year PrEP

Each month in Boyz the team from NAM aidsmap report the latest news on HIV and sexual health. This month, they also bring you the news from the International AIDS Society Conference on HIV Science in Mexico City. Keep up to date and read more on their website at

For the moment, PrEP always involves tablets. But some people struggle to remember to take pills or worry that other people will see the pills and know that they are on PrEP. Developing new ways to take PrEP is likely to be a focus for scientific research over the next few years.

The pharmaceutical company that makes contraceptive implants is working on a PrEP implant. The implant is a small, flexible plastic rod that’s placed under the skin in the upper arm by a doctor or nurse. It measures 4cm by 2mm and other people can’t see it.

They are trying a new drug for this implant. Called islatravir, it is extremely powerful even in small quantities and stays in the body for an unusually long time after it has been taken. This means that it could work in a long-acting implant.

The research is at a very early stage. The main aim of the first study in humans was to see how long the drug given with an implant would stay in the body for. Dr Randolph Matthews said that their tests showed that one implant gives enough drug to protect against HIV for at least three months and is likely to continue to work for a year or more.


The latest on event-based PrEP

There are two ways to take pre-exposure prophylaxis (PrEP) medications to prevent HIV.

The most common way is one pill, once a day, on an ongoing basis. Many people find this helps them get into the habit of taking the pills and means they will always be protected from HIV.

Another way is called event-based PrEP or on-demand PrEP. It involves taking pills just before and for a few days after having sex. You need to take double dose of PrEP (two pills) from 2-24 hours before having sex, and then additional pills 24 hours and 48 hours after the double dose. If the schedule sounds complicated to remember, you might find it easier to remember as 2+1+1.

If you have sex on several days in a row, one pill should be taken eacwwwh day until 48 hours after the last time you had sex. In which case, you might need to remember 2+1+1+1+1 for example.

At the conference last month in Mexico City, the World Health Organization announced that it had reviewed the scientific evidence on event-based PrEP and decided that it is a safe and effective option for gay men. They said that it should be offered as an alternative to daily PrEP.

Event-based PrEP could be suitable if you don’t have sex so often and you usually know in advance when you will have sex (at least two hours beforehand). If you are interested in taking PrEP this way, ask your doctor for advice. 

The research shows that event-based PrEP is effective for gay men, but not necessarily for other people.

Guidelines for sexual health doctors in the UK already support event-based PrEP. The backing of the World Health Organisation will help this approach be used around the world.


Advances in HIV treatment

There was also a lot of positive news about HIV treatment at the conference, about new drugs and new ways to take the drugs we already have.

Firstly, people taking a combination of just two anti-HIV medications, called dolutegravir and lamivudine, continued to have good results after almost two years on the treatment. Although most HIV treatment involves a combination of three drugs (sometimes taken together in a single tablet), when one of the medications is as powerful as dolutegravir is, it appears that two is enough. And it seems that a similar strategy could work with islatravir, the new drug that being tested as a PrEP implant, described above.

French researchers are testing out the effectiveness of taking HIV treatment four days a week, rather than seven days a week. Most people did well in the first six months of the study, but we should wait and see results on the longer-term effectiveness of the approach.

Monthly injectable HIV medications are likely to be available soon. Studies have already shown them to be effective but a new analysis at the conference looked into people’s experience of taking them. It found that most people were extremely satisfied and preferred the injections to their previous daily pills. While many found the injections a little painful, they were happy to put up with this.

New vaccine study

After a series of preliminary studies, scientists are now ready to test a vaccine to prevent HIV infection with almost 4000 gay men and trans women in Spain, Italy, Poland, the United States and four Latin American
countries. They are already testing a similar vaccine with women in African countries and results are expected in 2023.

There is a real chance that a vaccine that will protect people from infection could be available in the next decade. Most likely, it will only be partially effective (for example, preventing one out of every two HIV transmissions, rather than all of them), but it could still make a huge difference to stopping the spread of HIV.


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