By Matthew Hodson@matthew_hodson

What’s the best way of preventing HIV?

You’ve probably heard that you’re meant to ‘use a condom every time’, right? This message has been trumpeted so often, for so long, that for many people it’s become a reflex: the first thing to be said when there’s any discussion of safer sex.

But condoms are far from being the ‘best’ method of HIV prevention. If you look at the studies on how efficient the different ways of reducing HIV risk are, condoms are some way down the list.

Here are the HIV sexual safety scores: Condoms are about 90% effective when used every time you have anal sex (NB: this doesn’t mean that the risk of acquiring HIV is 10% if you use condoms, it means that if you use condoms the risk of transmission is one-tenth what it would have been if you hadn’t used condoms). This estimate on condom effectiveness has recently been revised upwards. Previously it was thought that condoms only prevented seven in every ten infections.

PrEP, when taken as directed, is now believed to be more than 99% effective. There have been a couple of cases where someone has become HIV-positive while taking PrEP but remarkably few, considering the hundreds of thousands of people who use PrEP now.

The only reason we talk about cases where PrEP appears to have failed is that they are so rare. When someone acquires HIV while using condoms it isn’t a story; it happens too often to be newsworthy.

Sex with someone who is HIV-positive but undetectable is safer than condoms or PrEP. The recent PARTNER 2 study of male couples confirms that when someone has maintained an undetectable viral load on treatment there is no risk of sexual  transmission (this is often referred to as U=U). In terms of HIV prevention, undetectable viral load doesn’t just make sex safer, it makes it safe.

Of course, there are other options. You can also bring your sexual risk down to zero by not having any sex at all, a ‘high on safety, low on fun’ strategy. If you just stick to mutual masturbation or frottage you’re protected too. Oral sex is fairly safe but it’s not 100% (although it is if the person you’re sucking off is undetectable).

Don’t get me wrong. I’m not telling anyone how to have safer sex. There are going to be a whole load of considerations for every individual. PrEP and treatment as prevention are brilliant at preventing transmission of HIV but they won’t help to prevent other STIs. Some people prefer a method of sexual safety that they can see and feel, like condoms, rather than one which depends on knowledge or trust.

Others find that any method of prevention which requires a physical barrier, or a pause in the heat of the moment isn’t going to work for them.

If you know that in the throes of passion, your mind altered by love, lust or chems, you end up ditching the condoms then PrEP is likely to be a good option for you. If the thought of taking daily medication frightens you then PrEP isn’t going to be so great.

I don’t care whether someone chooses condoms over PrEP or PrEP over condoms. What I do care about is that people are able to make an informed choice, without fear or stigma, that works for them.

The best method of HIV prevention is the one that works.  

Matthew Hodson is the Executive Director of NAM / aidsmap. For all the latest news about HIV and AIDS visit