Matthew Hodson: "PrEP is more effective than condoms"
Recently, pre-exposure prophylaxis of HIV (PrEP) is gaining momentum and is becoming one of the most popular strategies for reducing new HIV transmission. However, isolated cases of PrEP failures put it under attack. Matthew Hodson, a British expert on advocacy of people living with HIV and head of the NAM Foundation, posted in detail about PrEP in his Twitter account, its advantages and known cases of failures.
There have now been 4 established cases where someone who was taking their PrEP regularly has become HIV+. PrEP is not 100% effective. We have always known this.
Most often efficacy of 86% is cited, as this was the impact seen in several major PrEP studies. This is based on the effectiveness of PrEP as a strategy (i.e. people were given PrEP but the failures indicated that they did not take it as prescribed).
PrEP as a strategy should be compared to other safer-sex strategies. Some people who would say that their strategy is always to use condoms, actually don’t always use condoms. In fact 100% condom use is rare.
Even when condoms are used consistently, they can fail. Efficacy of 100% condom use may be as low as 70% (i.e. lower than PrEP use as a strategy).
Choosing partners on the basis of their presumed HIV status (sero-sorting) is also often ineffective as a strategy. As Public Health England bluntly state in their ‘HIV in the UK’ report, “unprotected sex with partners believed to be of the same HIV status is unsafe.”
So, onto the four cases of HIV infection when someone is adherent to PrEP.
Two of these were as a result of infection with a rare strain of HIV.
The third case (the Amsterdam case) was not due to a rare strain but took an unusual route (ed. initially having a localised infection within cells in the rectal tissues – probably facilitated by the inflammation brought on by LGV bacteria).
Due to lack of data we likely will never know with certainty the reason of the latest case of PrEP failure, just reported at CROI2018.
Over time there will be more cases of PrEP failure. And we will learn from these cases and may be able to make PrEP more effective as a result of them.
However PrEP, when taken consistently remains one of the most effective means of preventing HIV. It is more effective than condom use or sero-sorting as a strategy.
This isn’t to suggest that it’s right for everyone. Some people don’t want to take drugs. Some people struggle to be adherent. PrEP offers no protection against other STIs.
However for others PrEP is going to be the most effective and most appropriate method of managing their HIV risk. The tiny number of cases of HIV when on PrEP, in the context of the number using PrEP (77k in the US alone) are testament to that.
It’s vital that it is acknowledged that PrEP, just like other safer sex strategies isn’t 100% effective. But let’s not let isolated cases obscure how effective it is.
PrEP has played a significant role in bringing down new HIV infections.