Friday, April 22, 2011

Ever Increasing Numbers on Drugs is Not Reducing HIV Transmission

There's been a lot written about increasing the use of antiretroviral drugs, not just to treat people who are HIV positive, but also to reduce HIV transmission as well. One such strategy is called 'treatment as prevention', where those on antiretroviral treatment, under the right conditions, are said to be unlikely to transmit HIV to their sexual partners.

Another is called pre-exposure prophylaxis (PrEP), where HIV negative people take antiretrovirals because that has been shown to slightly reduce the risk for men who have sex with men, though not for women who have sex with men.

Reading the claims about 'treatment as prevention', you might think that it would make PrEP redundant. Advocates of treatment as prevention say that if a large proportion of the population in a high prevalence country were to be tested regularly, perhaps every year, and immediately put on ART if found to be HIV positive, transmission rates would drop rapidly.

But a group of researchers recently looked at sexual risk taking among patients on antiretroviral therapy in Nairobi's Kibera slum. And they note that many HIV treatment programs in such contexts do not include efforts to reduce HIV prevention beyond treating those already infected.

As a result, rates of sexual behavior considered to be risky remain high. It appears that, in their eagerness to get as many people on drugs as possible, the issue of preventing new infections has received little attention. And claims that this is not a problem, or even that it is not the case, sound rather hollow.

The researchers say "ART is often not enough to prevent HIV transmission, especially where there are high rates of inconsistent condom use and multiple sexual partners". Both these phenomena were found in Kibera.

Kibera may receive a lot more attention than most of the many slums in Nairobi. But the people living there only make up a fraction, perhaps a small fraction, of the total number of slum-dwellers in the city. Out of about 4 million inhabitants, as many as 60 or 70% may be living in slums.

It is noted that the tendency to treat people for HIV without also taking steps to reduce transmission is especially a problem in developing countries, which have weak health and social services. HIV prevalence in Kibera is estimated at about 12%, compared to 7.8% nationally.

People living in slums face multiple vulnerabilities, not just vulnerability to HIV transmission. Apparently "people living in urban informal settlements...have earlier sexual debuts, have more sexual partners, are more likely to use alcohol, and are less likely to adopt preventive measures against contracting HIV compared with urban residents in formal settings".

This research found that 28% of patients use condoms inconsistently (or not at all). Condom use was higher among those who were employed and among those who had been on treatment for longer. But women were three times more likely than men to report inconsistent condom use.

Married men were four times more likely to have had more than one sexual partner than married women, although only 9.5% in total said they had two or more sexual partners in the previous six months. Unmarried men were slightly less likely to have had more than one partner than unmarried women.

The context in which this research took place was described as "a relatively well-functioning ART programme with an inherent support structure focusing on patient education and information". But 'risky' behavior was still considered high, especially among those who had recently started ART, who are more likely to infect their sexual partners.

The authors conclude that "the roll out of ART cannot serve as a single preventive intervention, but must be linked with other preventive strategies for increased community effectiveness."

They also warn that "weak infrastructure and challenged health service delivery in informal settlements must be considered by policy makers and the donor community when developing future interventions to avoid the risk of negative effects, such as increased HIV transmission."

Putting more HIV positive people on ARV drugs has, for many years, led to very little money being spent on HIV prevention. While HIV positive people need treatment, and sooner rather than later, hundreds of thousands, perhaps millions of people have become newly infected with the disease.

Now those peddling drugs want to put HIV negative people on the same drugs, insisting that this will reduce transmission further. Drugs may reduce transmission, but neither of these strategies, treatment as prevention or PrEP, are identifying how so many people continue to be infected in somecountries and in certain parts of other countries.

Many African people live in conditions where the risk of being infected with HIV, either sexually or non-sexually, is very high. Neither of the above strategies even attempt to lower people's exposure to risk. Both of these exorbitantly expensive strategies, on the contrary, allow hundreds of thousands of people every year to be newly infected with a deadly disease.

[For more about pre-exposure prophylaxis (PrEP), see my other blog.]



Joyful said...

This is a shame. When all the ART becomes cost prohibitive (which I gather it is at times), then what? People need prevention education as much as treatment. How does one counteract or assist in helping a multipronged strategy. Surely some groups already know the need and are trying to correct it? I'm sorry I'm not very conversant in this area at all. More questions than answers or helpful commentary.

Simon said...

Hi Joyful
Well some treatment programs don't make any effort to prevent new infections. Some do make an effort, but only to reduce sexual transmission. And efforts to influence sexual behavior have not been very successful yet.

Few programs in developing countries have done much to address high rates of transmission of HIV through intravenous drug use or anal sex, partly because these activities are illegal, but partly because funders haven't been particularly interested in these modes of transmission.

Most large programs target the general sexually active population. But they don't seem to take note of the fact that, in the general population, HIV transmission is high even though levels of unsafe sexual behavior are not very high, suggesting that a lot of HIV transmission is not due to sex.

Therefore, throwing more and more drugs at the problem is not helping and it will not help in the future. Any infections diverted will be accidental and in some circumstances HIV transmission can be increased as a result of interventions based on faulty reasoning and/or incomplete data.