Sunday, February 26, 2012

Circumcision, PrEP and Vaginal Gel: HIV Prevention Show-Stoppers?

The highly unscientific but quite triumphalist term 'game-changer' appears frequently in the HIV literature. It has appeared in articles about pre-exposure prophylaxis (PrEP) after the iPrEx trial, and also in relation to three mass male circumcision trials. PrEP was said to reduce risk by 44% and circumcision by between 50 and 60%.

However, both of these figures were for relative risk. The respective figures for absolute risk were 2.3% and 1.3%. The term 'show-stopper' might be more appropriate than game-changer. The result of the trial of Tenofovir vaginal gel, also referred to as a game-changer, was said to be 51% effective; but little mention was made of the absolute risk reduction, which was about 5%. (See Joseph Sonnabend's very readable blog on relative and absolute risk.)

Why does this matter? Well, suppose the trial was between a group of people who were given a placebo, forming a control group, and a group of people who were given a herbal dose from the Old Man of Loliondo (look it up if you haven't heard), the second group being the intervention group. The difference between being given a placebo and given one out of many available herbal concoctions should be quite small. HIV incidence in both groups should be roughly the same. But suppose it was lower among those in the intervention group, and that 2 people became infected, compared to 4 in the control group. The absolute risk reduction would be so low that you might decide to spend your 24 Euro Cents for the herbal concoction on something else (though certainly not circumcision, PrEP or vaginal gel, which are at least hundreds of times more expensive).

I apologise to the Old Man and his acolytes, but he can take comfort in the fact that his concoction might easily reduce HIV infection risk as much as circumcision, PrEP or vaginal gel do. Indeed, it might even exceed their rather puny results, who knows? The relative risk reduction in the above example would be 50%. And if people were told that, they might think the Old Man is worth a visit. But they would be wrong. Even if the absolute risk reduction were a lot higher, people would be better advised to use condoms, much as they are when it comes to circumcision, PrEP and vaginal gel.

There have been numerous articles about how happy men and women are with circumcision programs, many of which have already been running for three or four years and claim to have operated on several million men to date. But there is also a recent article in a Zimbabwean paper questioning circumcision, even referring to it as a 'dangerous distraction'. In fact, the article uses the absolute risk reduction figure, so it's not surprising they question the wisdom of circumcising millions of men. It's just disappointing that more articles don't use this figure, or both figures, and question the exuberant press releases a bit more closely.

Apparently it was estimated that 750,000 HIV infections could be averted if 80% of adult males were circumcised. But this figure now seems difficult to support, especially as incidence is already dropping in some groups in Zimbabwe and in many other sub-Saharan African countries and has been for quite a few years. Gregory J. Boyle and Gregory Hill have specifically pointed out how the superficially impressive 60% relative risk reduction needs to be compared to the 1.3% absolute risk reduction. Hopefully, people will use these figures to make up their own minds before being railroaded into being circumcised or into persuading their partner or relatives to be circumcised. They also raise the rather embarassing fact that in quite a number of African countries, HIV rates are higher among circumcised people than uncircumcised people.

It's great that these questions are being asked, in an academic paper and in a newspaper. But none of the serious objections to circumcision, PrEP or vaginal gel are new to those carrying out research in these areas. There appears to be a cabal of HIV 'experts' who are doing everything they can to persuade people of the effectiveness of various public health interventions by selectively publishing favorable data and suppressing or giving far less attention to less favorable data.

[For more about non-sexual risks for HIV transmission, see the Don't Get Stuck With HIV site and blog.]



Joseph said...

They want to circumcise 80% of the men to see the said "effect."

But let's buy into this for a minute. Let's assume for a second that that 60% were absolute.

The next question is, what about countries where circumcision is already close to universal, but where this 60/40 ratio fails to manifest?

Data from six African countries shows that HIV is more prevalent among the CIRCUMCISED in those countries.

I'm quite sure you know about Cameroon, Ghana, Lesotho, Malawi, Rwanda and Swaziland. (And yet they want to circumcise everybody there!)

But the 60% number fails to correlate in other countries as well.

According to Malaysian AIDS Council vice-president Datuk Zaman Khan, more than 70% of the 87,710 HIV/AIDS sufferers in the country are Muslims. In Malaysia, most, if not all Muslim men are circumcised, whereas circumcision is uncommon in the non-Muslim community. 60% of the Malaysian population is Muslim, which means that HIV is spreading in the community where most men are circumcised at an even faster rate, than in the community where most men are intact.

In the Philippines, the majority of the male population is circumcised, as it is seen as an important rite of passage. In the 2010 Global AIDS report released by UNAIDS in late November, the Philippines was one of seven nations in the world which reported over 25 percent in new HIV infections between 2001 and 2009, whereas other countries have either stabilized or shown significant declines in the rate of new infections. Among all countries in Asia, only the Philippines and Bangladesh are reporting increases in HIV cases, with others either stable or decreasing.

Joseph said...

But what about AMERICA, the country behind the circumcision push in Africa?

When the HIV/AIDS epidemic hit, circumcision rates were at 90% or so, and yet circumcision failed to avert an HIV epidemic.

And, it hasn't stopped other STDs either.

In America, the majority of the male population is circumcised, approximately 80%, while in most countries in Europe, circumcision is uncommon. Despite these facts, our country does poorly.

In fact, AIDS rates in some US Cities rival hotspots in Africa. In some parts of the U.S., they're actually higher than those in sub-Saharan Africa. According to a 2010 study published in the New England Journal of Medicine, rates of HIV among adults in Washington, D.C. exceed 1 in 30; rates higher than those reported in Ethiopia, Nigeria or Rwanda.

The Washington D.C. district report on HIV and AIDS reported an increase of 22% from 2006 in 2009.

According to Shannon L. Hader, HIV/AIDS Administration, Washington D.C., March 15, 2009,
"[Washington D.C.'s] rates are higher than West Africa... they're on par with Uganda and some parts of Kenya." Hader once led the Federal Centers for Disease Control and Prevention's work in Zimbabwe.

80% in the US never prevented HIV. But it's suddenly going to start working miracles in Africa? Really? Something's WRONG.

Simon said...

Hi Joseph, yes, the 80% figure is strange because about 85% of Kenyans are already circumcised. Efforts are being concentrated on the small population of uncircumcised men because it's one of the areas where lack of circumcision is correlated with high HIV rates. But in one tribe that practices 100% circumcision, HIV prevalence is very high also, but mainly among women (the Luhya of Western Kenya).

As you say, there are many countries where HIV prevalence is higher among circumcised men and I don't know how those pushing male circumcision will get around that. UNAIDS, the WHO and the US CDC, PEPFAR, etc, tend to ignore such details in their literature.

You're right about the US but even those pushing the programs accept that circumcision doesn't reduce transmission during male to male receptive anal sex, which means they would probably also accept that it doesn't work for male to female anal sex either. But heterosexual HIV transmission is said to be highest among black American men, who also tend to be circumcised!

Joseph said...

"But in one tribe that practices 100% circumcision, HIV prevalence is very high also, but mainly among women (the Luhya of Western Kenya)."

Circumcision proponents ought to be ashamed. Weren't they the ones who were saying that women were supposed to be "indirectly protected" through male circumcision?

Talk about "trickle-down HIV prevention."

"...even those pushing the programs accept that circumcision doesn't reduce transmission during male to male receptive anal sex, which means they would probably also accept that it doesn't work for male to female anal sex either. But heterosexual HIV transmission is said to be highest among black American men, who also tend to be circumcised!"

What a disgraceful waste of funds. Africans can't get food, clean water or even safe healthcare. But let's spend millions on a dubious mode of prevention that has consistently proven to fail! Let's exacerbate the HIV problem by providing an alternative to the most effective mode of protection known to us!

When this charade finally comes crashing down, who is going to hold these idiots responsible?

Petit Poulet said...

It is very simple to model and demonstrate that relatively small decrease in condom use can completely undo any advantage in circumcising a large percentage of the men in a community. If, as many suspect, that circumcision is not as effective as advertised, then a circumcision program that lowers condom usage could result in an increased number of HIV infections.

Simon said...

Yes, it's well known that the gains from certain 'prevention' interventions, if there are any gains, could easily be lost through changes in behavior. But maybe no one will notice. Figures for new infections are often vague enough and most countries couldn't really tell you with any certainty how many new infections there each year, how many deaths, how many on treatment, how many new patients on treatment, etc.