Pre-Exposure Prophylaxis or PrEP

Pre-exposure prophylaxis (PrEP) involves putting HIV negative people on antiretroviral drugs (ARV) with the aim of protecting them from HIV infection. This blog looks at some of the pros and cons of PrEP.

Wednesday, July 27, 2011

Wagging Fingers Hasn't Worked; Let's Try Pills

It is very reassuring that a commentator in Kenya has mentioned, albeit briefly, that providing ARVs to HIV negative people will strain resources in a country where it is not even possible to supply all HIV positve people with them.

Many people don't have food, water, cheap drugs for everyday, but deadly, diseases, contraception and family planning, proper education, infrastructure, and a great many other things. Why the obsession with grossly overpriced drugs that will not make any material differenc to most people's health?

But there are some odd remarks in the article. One person mentioned in the article that she had not had sex with her husband for the first three years after finding out that he was HIV positive. Then she started to use condoms.

So far so good. Condoms give a good level of protection if they are used properly and used all the time. There are all sorts of stories about condoms breaking but this should be rare if people really know how to use them properly. And at least condoms are cheap and have other benefits, protecting against sexually transmitted infections and preventing unplanned pregnancies.

But the article is about using drugs to reduce HIV transmission. This would be in the form of pre-exposure prophylaxis (PrEP), where a HIV negative person takes an antiretroviral drug regularly to reduce the probability of being infected, or 'treatment as prevention', where the HIV positive person takes ARVs which reduce the viral load to a level where HIV is a lot less likely to be transmitted.

If condoms are used, is the risk that the HIV negative partner faces going to be reduced further when they also take PrEP? Perhaps so, perhaps a belt and braces policy gives more protection.

But if the HIV positive partner is on ARVs, taking them correctly, responding to them (to the extent that their viral load is low, etc), does the HIV negative partner need to be taking PrEP? Couldn't the HIV negative partner just make sure that condoms are used?

The more important questions are about whether there will be enough money for all HIV positive people to receive the drugs and other care they need, as well as for HIV negative people to receive the most effective prevention assistance available.

Currently, only 20-40% of people in need of ARVs are receiving them. Will the need for PrEP be given priority over the need for ARVs, given that PrEP is for people who are healthy and normal ARV treatment is for people who are sick and will die without the drugs?

But even 'treatment as prevention' is not that straightforward. The majority of people in most African countries do not know their HIV status. Even the majority of HIV positive people do not know their status. How easy will it be to identify all HIV positive people and keep on identifying new infections for as long as they occur.

Apparently Swaziland is going to test its entire population and put everyone found to be HIV positive on ARVs, effectively, 'treatment as prevention' or 'test and treat'. There are only 1.2 million Swazis but an estimated 200,000 of them are HIV positive.

Yet only about 60,000 HIV positive Swazis are on ARVs and the country doesn't even have enough supplies for them. Similar shortages have occurred in other African countries. Health services can barely cope with keeping a fraction of people on treatment, let alone all those who need them.

The Kenyan article continues with the sort of honesty that you wouldn't normally find in an article about HIV: prevention so far has had little impact and the rate of new infections is still very high; sexual behavior change, the main aim of most prevention programs, has not occurred to any great extent.

But UNAIDS and the HIV orthodoxy have, according to the article, been targeting the wrong people all along. They have been talking about reducing numbers of partners, using condoms and even giving up sex altogether. But many new infections occur in mutually monogamous couples, often among people who take precautions and who don't take risks.

The biggest problem with both PrEP and 'treatment as prevention' is that we have been very poor at identifying where new infections are coming from, so we are still, many years and billions of dollars later, in a poor position to know how to traget these expensive interventions, if the money does miraculously appear.

HIV prevention programs are usually targeted at whole populations, many of whom are not at risk. But even those who are not 'at risk' by UNAIDS' criteria become infected with alarming frequency. The plan seems to be to put as many people as possible, HIV positive and HIV negative, on drugs because, rather than despite the fact that, we haven't a clue why most people are infected.

ARVs appear to have an effect, whether used for PrEP or 'treatment as prevention', but we don't really know who to give them to. So we are going to try and give them to as many people as possible, in the hope that it will work, apparently. Is this modern medicine? It's no wonder people are suspicious about 'public health' programs.


1 comment:

Simon said...

According to this article on the BBC website, it's not just ARVs that Swaziland has run out of. The country is also suffering from food shortages. ARVs can not be taken on an empty stomach and ever since large scale ARV programs have been rolled out, many patients have complained that lack of food is a bigger priority for them than drugs.

The 'eating cow dung' is probably in need of more careful research, though.

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