Les pilules de prévention du VIH devraient-elles être disponibles sur le NHS ?

HIV: the long-term costs

That is precisely the balancing act governments in England, Wales and Scotland have been at work on where PrEP - Pre-Exposure Prophylaxis (medication that prevents VIH) is concerned.

The good news is that extraordinary progress has been made in the treatment of HIV - for people diagnosed with HIV at the age of 20, life expectancy increased from 36 to 52 years over just half a decade from 2000-2 to 2006-7. Many patients with HIV live full and productive lives - but it is still an incurable, lifelong condition which needs lifelong treatment.

La lifetime cost of treatment for a single HIV patient is about £360,000, even before the human cost is taken into account. Anything that cuts the numbers of patients needing this treatment with multiple drugs has a fair chance of saving our society money in the long term.

Truvada®, also known as PrEP (pre-exposure prophylaxis), cut the risk of contracting HIV by 86% in a 2015 study of over 500 men at high risk. Of course, 'relative risk reduction' can be misleading (buying two lottery tickets increases your likelihood of winning by 100%, but the odds are still minuscule).

But to put it into perspective, within a year in this study, 19 men out of 270 became HIV positive, compared to three in the PrEP group. Multiply that by the tens of thousands of people at high risk, and the numbers of cases prevented is eye-boggling. So is the saving in terms of the long- term cost of treating them.

In 2016, NHS England announced that it would not fund PrEP, despite admitting in March 2016 that PrEP treatment 'can be highly effective in preventing HIV as long as the drugs are taken regularly'. Its excuse was that if it did, it would lay itself open to legal challenge, both from manufacturers of competitor drugs and from groups with a vested interest in other treatments the NHS might not fund if they used the money on PrEP. In a statement, they said they had 'considered and accepted NHS England's external legal advice that it does not have the legal power to commission PrEP'.

As a sop, they explained that they were 'committed to working with local authorities, Public Health England, the Department of Health and other stakeholders as further consideration is given to making PrEP available for HIV prevention' - but failed to put a penny behind these promises. Leading sexual health charity condemnation was fast and damning, and the charity NAT (National Aids Trust), with backing from the Local Government Association, took NHS England to the High Court. At an appeal hearing, three judges decided unanimously that NHS England does indeed not have the legal power to commission PrEP.

Despite this ruling, the NHS postcode lottery is alive and kicking in the UK. If you live in Scotland, PrEP is widely available through NHS sexual health clinics for people who are most likely to benefit from it. These include cis- and transgender gay and bisexual men, other men who have sex with men, and transgender women who:

• Are partners of HIV positive people with a detectable viral load.

• Have had a documented bacterial rectal infection sexuellement transmissible in the last year.

• Have had anal sex with two or more partners in the last year and are likely to do so again.

Likewise, in Pays de Galles there is no cap on the number of people who can be treated with PrEP, as long as they fulfil criteria which mean they are most likely to benefit from it. In the first instance, however, the funding will run for three years from 2017 as part of the PrEPared Wales project.

In England, the PrEP Impact Trial started enrolling 10,000 people in October 2017. The criteria to get access to the drug are similar to those in England and Wales. It's not the same as a full roll-out and it's not ideal - but it's a start.

There's no point shouting that high-risk individuals (mostly men who have unprotected sex with men) shouldn't do it - they are doing it, and they're going to carry on doing it. From a moral perspective, if we're going to refuse them treatment, we should deny treatment to anyone who's en surpoids, or a smoker, or likes a glass of wine, or went on holiday to an exotic location and came back with paludisme.

In the long term, the NHS will carry on picking up the tab for a lifetime of treatment once patients are diagnosed with HIV. Some of the drugs we have now may get much cheaper once they come off patent. But HIV is a virus, and viruses evolve, so we're likely to continue to need new drugs, at a cost of about £1 billion each to develop. Prevention or cure/lifetime-treatment-because-we-can't-cure-it? From where I'm sitting, there's no contest.