Edging closer to an AIDS cure
Many countries cannot afford the high cost of treat-ment and depend on international aid.
Despite the progress made in the field of medical research since the discovery of AIDS in 1981, it is too early to speak of a cure. In 1983 we identified the agent responsible for the progressive failure of the immune system, later naming it the human immunodeficiency virus, H.I.V.
The last 30 years of research have provided us with profound insights into how the virus replicates itself, spreads and lies dormant in latent reservoirs within the human body. This understanding led to the revolutionary breakthrough of combination antiretroviral (ARV) therapy in 1996, which has reduced patient mortality rates by more than 85 percent.
Not only are ARVS effective in treating HIV, they also have preventive applications. As early as 1994, a clinical trial showed that zidovudine (AZT) effectively prevented mother-to-child transmission of HIV. Recent studies confirm that ARVS significantly reduce the risk of the virus being sexually transmitted. These are major developments. The fact that ARVS not only save lives, but also prevent new infections and thus check the AIDS pandemic, is a powerful argument in favor of speeding up universal access to treatment.
In Botswana, where 90 per cent of patients are under treatment, new data released by Unaids suggests that the number of new HIV infections ‘‘is 30 per cent to 50 per cent lower today than it would have been in the absence of antiretroviral therapy.’’
Yet many countries cannot afford the high cost of treatment and depend heavily on international aid. Unfortunately, the global financial crisis threatens to disrupt the flow of funds, as donor countries renege on their commitments. Several recipient countries are already starting to run out of ARVS. Even more worrying is the risk that this situation could lead to the development of newly resistant strains of HIV and produce a fresh pandemic.
It is essential that innovative, durable sources of funding are found. For years a number of voices have been calling for proceeds from a possible financial transaction tax to be channeled to health initiatives in developing countries. We must do all we can to bring this proposal to the attention of G-20 leaders.
Concurrently, we must redouble our efforts to develop new therapies. Though significantly alleviated by ARVS, living with HIV remains a heavy burden. Combination ARVS must be taken for life, and they are not without side effects. They do not completely eradicate the virus: Its persistence in latent reservoirs is associated with chronic generalized inflammation of the immune system.
Thus patients do not recover a full life expectancy and are under increased risk of cardiovascular and neurological diseases, cancer and premature aging. Eradicating HIV will long remain a dream. Even so, some models lead us to believe part of the dream could come true if we succeed in developing new short-term therapeutic strategies, which may result in lifelong remission without the need for drug therapy.
Aunique study in France, named Visconti, has assembled 18 patients who were tested within two to three months after HIV infection and immediately placed on ARV. Some years later, with their doctors’ consent, they ended their ARV treatment and have since kept their infections in check. The study confirms the benefits of treating HIV at the very early stages of infection. There is an immensely valuable store of knowledge to be gained from analyzing the immunological characteristics that made therapy redundant for these patients.
As natural carriers of the simian immunodeficiency virus (SIV), from which HIV originated, African monkeys present a final object of study. Unlike HIV in humans, SIV-infected monkeys do not develop AIDS; any immune reaction to the virus is quickly subdued. The virus multiplies among monkeys, without provoking the inflammation observed in human infection.
The mechanisms we must induce in order to trigger a protective response against HIV/AIDS remain a mystery. A combination of vaccines and therapeutic approaches will most likely prove necessary. This is the focus of a working group formed under the auspices of the International Aids Society (I.A.S.), composed of international scientists aiming to develop a global scientific strategy to deal with HIV persistence, in the hope that we will one day live in a world without AIDS.
Research surrounding HIV/AIDS has useful implications beyond the epidemic itself. HIV is a tool that helps us to better understand the specific mechanisms at the heart of our immune systems. There is also much to be learned from research in cancer and other chronic pathologies linked to inflammatory abnormalities. In this time of crisis, we are faced with two choices: Either we work in collaboration in a spirit of solidarity, as we did at the beginning of this epidemic, or we adopt an ‘‘every man for himself’’ approach, to the detriment of us all.