New HIV Prevention Methods Face Difficult Challenges

By Robert K. Altman
Reprinted with permission from the New York Times

An array of promising new methods to prevent the spread of H.I.V. may become reality in the near future, but most countries are unprepared to provide them to the hundreds of millions of people at risk of becoming infected, an international panel of experts reported at the International AIDS Conference in Toronto this week.

Findings from large studies of some prevention methods, like the use of microbicides and male circumcision, are expected within the next five years, some possibly in about a year, the panel said at the 16th International Conference on AIDS.

But the studies are complex, the methods will not offer a magic bullet to prevent the disease, and whatever preventive techniques are found to be effective will probably be combined with existing prevention strategies, the panel of 50 experts cautioned. The experts also urged the world to address the practical and ethical challenges that they said threatened to slow or derail critical research projects on many prevention measures.

In addition to vaccines, circumcision and microbicides - gels and creams that could be inserted vaginally or rectally to block HIV infection - the report focused on three methods:

Diaphragms and other cervical barriers that could help protect women from HIV and other sexually transmitted diseases;

A drug to suppress herpes, which infects up to 70 percent of people in some parts of Africa;

Antiretroviral pills like tenofovir (Viread) to prevent infection among prostitutes, drug injectors and other people at high risk of becoming infected. An analogy would be taking anti-malarial drugs before traveling to a malaria-infected area. A study of 400 at-risk women in Ghana, to be reported at the AIDS conference, found that tenofovir was safe for uninfected women. Findings about the drug's effectiveness are expected later.

There is an urgent need to make proven prevention measures widely available, because four million people are infected with HIV each year but fewer than one in five people who are at high risk for infection have access to such preventive measures.

As treatments have proved effective, "the harsh reality is we are quickly falling behind in HIV prevention," Dr. Helene Gayle, the president of the International AIDS Society, which is the main organizer of the conference, said at a news conference.

No new preventive measure under study is likely to be 100 percent effective, a fact that will increase the difficulty of putting the methods into practice, the panel said, adding that educational campaigns will be needed to integrate the new methods with effective older ones.

The panel members cautioned AIDS workers to take steps to avert the complacency about risky behavior that could follow the broader use of effective preventions.

More donor financing will be needed to introduce and deliver the new methods, the panel, known as the Global HIV Prevention Working Group, concluded. The panel members made a number of recommendations, including finding ways to help poor countries train enough health workers to carry out male circumcision safely.

Last year, a study conducted in South Africa found that circumcised men were 60 percent less likely than non-circumcised men to be infected with HIV by women who are sex partners. In 2007, the findings should begin to come in from three studies under way in Kenya and Uganda. The studies are aimed at confirming the South African study and determining whether male circumcision also reduces the risk of HIV transmission from men to women.

Continuing prevention studies involve about 80,000 people, and tens of thousands more people will be needed for future studies that are intended to confirm early findings and to test newer versions of old methods, the panel said. It warned that the wide array of studies was rapidly exhausting the number of sites adequate for them, the pool of potential volunteer participants and the trained staff members necessary to carry them out.

The panel also recommended the development of new ethical guidelines for conducting clinical trials in poor countries.

Embarrassed officials in Cameroon and other countries have stopped a small number of prevention trials because of incidents involving poor communication between researchers, trial participants, community leaders and government officials.

No formal agreement exists on which prevention services should be provided to participants in trials. Another ethical issue is determining whose responsibility it is to treat participants who become infected during a trial. Infections inevitably occur in such trials, Dr. Gayle said.

08//18/06

Source
R K Altman. Experts Warn Scientific Gains on HIV Not Enough. New York Times. August 16, 2006.