Progress continues in fighting the AIDS epidemic, but the pace is slow. The rate of HIV infection has been reduced by almost 20 percent over the last 10 years, to fewer than 2.7 million infections per year. The number of people dying from AIDS has gone down by more than 20 percent in the last five years, to fewer than 2 million annually. Given all the lives that are at stake, I am impatient enough about this that I am willing to be viewed as a troublemaker by people who are happy with the status quo. The war against AIDS is being waged on two fronts—treating those who are already infected and preventing new infections. Treatment continues to be scaled up, with more than 5 million people receiving HIV drugs. This is a great success story. Rich country generosity has been crucial and the execution in poor countries has been strong. However, there will not be enough money to treat everyone who will become infected if we don’t halt the progress of HIV. Because we don’t have a cure for AIDS, treatment has to continue for a patient’s entire life. That means costs continue to increase as you put more and more people on treatment. Even without including people who will become infected in the future, the cost of treating the 33 million people living with AIDS today would be over $40 billion per year at current costs—over four times as much as is provided in aid today. To minimize the funding gap we need to reduce per patient costs of treatment. Drug costs have already been reduced to less than 20 percent of treatment costs. Most of the future savings will have to come from treatment models that reduce personnel, laboratory, and overhead costs. The difficulty of funding treatment makes it clear how important it is to prevent new cases. The sooner we make progress the better. There needs to be a sense of urgency that doesn’t exist yet.
Prevention breaks down into several different areas. The easiest should be preventing mother-to-child transmission since it simply involves giving a mother drugs to prevent transmission to her child. There is a lot of focus on getting from the current number of over 300,000 infections per year to zero. Another prevention approach is counseling people to change their behavior, including avoiding risky acts and using condoms.
Then we have prevention approaches that rely on new tools. We now have three tools that have shown significant impact. The first is male circumcision, which I discussed last year. Amazingly, teenagers in communities with high HIV incidence show a high willingness to be circumcised. Kenya is leading the way with over 200,000 circumcisions performed. However, there are over 10 million men in high-risk settings in Africa who would benefit from male circumcision, and we should be scaling up 10 times faster than we are.
Another new tool is a vaginal microbicide gel that a woman can use to protect herself. A recent trial showed a gel containing tenofovir protected women against infection. Now the question is how long it will take before the gel is rolled out on a large scale. As someone outside the field, I am surprised at the number of steps it takes. First the product has to be licensed, which requires approvals from regulatory groups in both the country where the product will be used and donor countries. Many of these approval steps happen serially rather than in parallel, and it is only when the entire approval process is complete that the product can be rolled out. Even then the process isn’t complete because a whole system for delivering the product needs to be put together, and again a lot of these steps proceed in a slow serial fashion.
Another new prevention tool, PrEP (Pre-Exposure Prophylaxis), involves someone without HIV taking an anti-HIV drug on a regular basis to block infection. A PrEP trial showed a strong prevention benefit for the participants who consistently used the drugs and a weaker impact when all the participants were included. With both microbicides and PrEP I think countries with large epidemics should figure out how to do large community trials as soon as possible. This would shorten the time before all patients have these lifesaving tools by many years.
If the United States had an epidemic where almost half the girls in large neighborhoods contracted a terrible disease, we would find a way to cut through all the complexity. With HIV it is more difficult since there are many countries involved. But we need to work creatively to shorten these delays.
The best tool would be a vaccine for HIV. The scientific progress on this has gone well. The positive results of the trial in Thailand were a turning point for the field, and blood samples from the volunteers are being studied in depth for lessons about why that vaccine worked but only to a limited degree.
Clockwise, from top left: Physician examines a six-year-old girl (Siem Reap Province, Cambodia, 2010). Transgender sex workers at a drop-in center (Chennai, India, 2008). Female sex workers are trained how to use condoms at a mobile clinic (Mumbai, 2009). Sign advertises the use of condoms to prevent HIV infection (Andhra Pradesh, India, 2009).
There has also been an explosion in the discovery of antibodies that block HIV infection. Scientists don't yet know how to make a vaccine that will cause patients to generate lots of these antibodies, but there are several approaches that look promising and will be ready to go to trials in the next few years. In order to get a fully effective HIV vaccine we will almost certainly need several rounds of trials where we learn and improve the candidate vaccines. So to get a vaccine as soon as possible we need to minimize the length of the trials and the time between trials. So far each cycle has taken over five years. The field needs to look into how to shorten this so that progress matches the urgency of the problem.
0 comments:
Post a Comment