PrEP: a flawed prevention strategy for HIV/AIDS
by Peter Saunders | October 06, 2016
The High Court of the United Kingdom recently that the National Health Service in England can fund a drug that can reduce the chance of people catching HIV whilst engaging in high-risk sexual activities.
NHS England had previously argued that local municipal councils should provide PrEP (“pre-exposure prophylaxis”) as “health prevention” is their responsibility.
But Mr Justice Green said that NHS England had “erred” and that both it and the local authorities were able to fund the drugs. Summing up, he said:
“No one doubts that preventative medicine makes powerful sense. But one governmental body says it has no power to provide the service and the local authorities say that they have no money. The clamant [the National Aids Trust] is caught between the two and the potential victims of this disagreement are those who will contract HIV/Aids but who would not were the preventative policy to be fully implemented.”
The ruling has understandably evoked praise from gay rights campaigners and AIDS charities but consternation from NHS England which intends to appeal the decision. It is concerned about the effectiveness of the strategy, the precedent it creates for funding other “disease prevention” measures and the way resources might be drawn from other health priorities were it to get the go-ahead.
The once a day pill known as PrEP, trade-named Truvada, consists of two antiretroviral medications used for the treatment of HIV/AIDS (tenofovir and emtricitabine or TDF-FTC) and costs £400 a month per person. The total cost to the health service could be in the order of £10 to 20 million.
It is currently used in the United States, Canada, Australia and France to help protect the most at-risk gay men.
According to the CDC (Centers for Disease Control) in the US, PrEP is for people who do not have HIV but who are at substantial risk of getting it. It should be used in combination with other “HIV prevention” methods, such as condoms, but even in these circumstances is not foolproof.
The CDC reports studies have shown PrEP reduces the risk of getting HIV from sex by more than 90 percent when used consistently. Among people who inject drugs, PrEP reduces the risk of getting HIV by more than 70 percent when used consistently.
But these figures are what is achievable with good adherence (consistent use), and many of those most at risk are very likely not to adhere with taking the pills regularly.
An authoritative Cochrane review is far less reassuring. Overall, results from four trials (Baeten 2012; Van Damme 2012; Grant 2010; Thigpen 2012) that compared TDF-FTC versus placebo showed a reduction in the risk of acquiring HIV infection by about 51 percent.
Marked differences between the studies were attributed to differences in levels of adherence.
As one major review has concluded:
“The efficacy of PrEP is dependent on adherence, and adherence to PrEP medications in efficacy studies has been variable, raising questions about whether persons who are prescribed PrEP in clinical settings will be adherent enough to derive protection.”
Furthermore the drug’s use may in fact lead to a paradoxical increase in other sexually transmitted infections (gonorrhoea, chlamydia, etc) by encouraging more high risk behaviour from those who have been lulled into a false sense of security.
This well-known phenomenon whereby applying a prevention measure results in an increase in the very thing it is trying to prevent is known as “risk compensation”. I have previously blogged on the fact, surprising to some, that morning-after pills don’t actually cut teen pregnancy rates and instead increase the incidence of sexually transmitted infections (see also here).
The term “risk compensation” has also been applied to the fact that the wearing of seatbelts does not decrease the level of some forms of road traffic injuries, since drivers, feeling more secure, are thereby encouraged to drive more recklessly.
In the same way making PrEP freely available to already promiscuous homosexuals could well encourage more sexual risk-taking and more sexually transmitted disease as a result. Any effect on decreasing HIV transmission rates is then cancelled out by rising levels of promiscuity.
Many will be shocked at the levels of promiscuity reported in these high-risk groups. In one study in the Cochrane database, during screening, participants reported an average of 12 coital acts per week with an average of 21 sexual partners in the previous 30 days.
It is only when these facts are known that the highly addictive nature of high-risk sexual activity, especially amongst male homosexuals, becomes evident.
PrEP is not a prevention strategy at all. It is rather a harm reduction strategy aimed at lessening the damage that people addicted to high-risk sexual behaviours are doing to themselves. More akin to clean needles for drug addicts, filter cigarettes for smokers, protective gloves for compulsive burglars or seatbelts for habitual joy-riders.
As has been recently argued with respect to PrEP for drug addicts, “PrEP is not ready for our community and our community is not ready for PrEP”. We need instead to address the underlying structural drivers and social context of the HIV epidemic and ask what it is that actually leads people to behave in this way.
PrEP may reduce the risk of HIV transmission significantly but it does not eradicate it. That is because it is not actually a “prevention” strategy at all but a “harm reduction” strategy. And lack of adherence and “risk displacement” simply add to the problem. This means that those who rely on PrEP for protection against HIV are still effectively playing Russian roulette, with the willing assistance and collaboration of health professionals.
NHS England is right to challenge this judgement. We will need much more evidence that PrEP is truly effective in practice before embarking on this strategy, which brings us back to the bottom line in all this: the only way of preventing HIV infections, as opposed to reducing the chance of catching them, is by avoiding the high-risk sexual behaviours that lead to them.
Peter Saunders is Chief Executive of the Christian Medical Fellowship in the UK and was formerly a general surgeon. He also serves on the boards of the International Christian Medical and Dental Association and Coalition for Marriage and is campaign director for the Care Not Killing Alliance. This article has been republished from the CMF blog.