HIV News from NAM aidsmap

What happens when PrEP doesn’t work?

Each month in Boyz the team from NAM aidsmap report the latest news on HIV and sexual health. Keep up to date and read more on their website at

PrEP – the medication you can take to prevent HIV infection – works incredibly well. When people take it as prescribed, it stops well over 99% of HIV transmissions. It’s more reliable than a condom.

But there have been a handful of cases in which people have picked up HIV despite using PrEP. When doctors have been aware of them, they have carefully recorded and investigated the particular circumstances of the cases.

A lot of attention has been paid to the cases. That’s perhaps because they are the “exception that proves the rule”. The rule is that PrEP is incredibly effective and the rarity of these cases shows that to be true.

One such case, of a 34-year-old Swiss gay man, was reported at the European AIDS Conference in November. He knew a lot about PrEP and took it each day, as prescribed. Nonetheless, he was diagnosed with HIV in July this year.

There are some specific circumstances – or a combination of circumstances – which could possibly explain this. The most obvious one is that he took a short break from PrEP a few weeks before his diagnosis. However, he says he didn’t have sex until a week after re-starting daily PrEP. Close analysis of his HIV antibodies suggest an infection before his break. Nonetheless, it’s always possible that he did in fact have sex during the break.

Other factors may be more important. He had a nasty case of the STI lymphogranuloma venereum (LGV) in his backside, which could have made his tissues more vulnerable to HIV. It’s possible, but unlikely in this case, that he may have caught a virus with a degree of pre-existing resistance to PrEP. And he had unusually low levels of the PrEP drugs in his blood. These levels would normally be OK, but perhaps not in combination with two or three other factors.

Dr Benjamin Hampel of Zürich University Hospital told the conference that small numbers of cases of ‘PrEP failure’ are likely to keep on happening. He said that we shouldn’t get hung up about trying to work out which – if any – have watertight evidence of 100% adherence. That is extremely difficult to prove.

But he said that what scientists need to do now is collect details of all the cases of HIV infection that occur in PrEP users around the world and look at them together and see if they can see any patterns.


Weight gain and HIV treatment

The anti-HIV medications that are used today have far fewer side effects than the ones that people took ten or 20 years ago. As there are so many different drugs that have a powerful effect against HIV, doctors can focus mostly on choosing a combination that is easy to take and has very few side effects.

But new side effects do sometimes appear. One of the most important topics discussed at the recent European AIDS Conference was people putting on weight after starting HIV treatment. Doctors have noticed that some of the patients have put on several kilos after a year or two on treatment.

Part of the explanation is about people who were not in good health before starting HIV treatment, with the body needing extra energy to fight off HIV or other health problems. When their health improves and they no longer need that extra energy, some of it turns into fat.

But that isn’t the whole story – some specific anti-HIV drugs and drug combinations seem to cause more problems than others. Some of these medications are quite new ones that have only been available for a few years.

It’s also clear that black people and women have had the greatest gains in weight. This might be due to genetic differences, but researchers do not yet have a clear understanding of the reason why. Most research studies for new HIV medications over-recruit white men and don’t include enough black people and women, making it harder to properly research the issue.

If you’re taking HIV treatment and are worried that it is making you put on weight – especially if you are black – speak to your doctor. They can explain whether the medication you are on is one of the ones thought to be linked with weight gain and perhaps help you find an alternative.


Memory and concentration problems

Considerably fewer Swiss people with HIV reported frequent memory loss, concentration difficulties and reasoning difficulties in recent years. Between 2013 and 2017, the proportion reporting one of these problems fell from 20% to 11%.

The researchers think this may be because more people are starting effective HIV treatment sooner. This helps prevent one form of dementia that occurs when HIV (or the response of the immune system to HIV) directly affects the brain and causes cognitive problems. This problem is now quite rare.

There can be lots of causes for memory and concentration problems. Some of the most common are heavy drinking or drug use (especially when they are used regularly over a long period of time). They are also linked to depression, anxiety and other mental health problems. And they could be part of Alzheimer’s disease or another form of dementia.

Compared to people without any problems, people in the study with these problems that didn’t improve were more likely to have previously had a serious infection affecting the brain or spinal cord, to have less than perfect adherence to HIV treatment, or to have had depression.


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