While the public has heard enough and more about America's keenness to defuse India's atom bomb, not many know that it is probably the AIDS bomb which is giving Uncle Sam more sleepless nights. For, even as the AIDS epidemic plateaus in America, there is every possibility that HIV could re-enter the country in the distant future unless simultaneously contained all over the globe, a fact that worries many health experts.

So, India's AIDS scenario too is getting some American attention. Even as the Indian atom bomb is slowly being neutered through the high-profile parleys between Strobe Talbott and Jaswant Singh, AIDS is assuming centre-stage. At a hush-hush, closed-door meeting recently held inthe capital, top American and Indian AIDS experts met to chalk out a joint strategy to handle the scourge of HIV and see if a vaccine could become a real possibility.

At the end of the brainstorming, the two countries decided that the road ahead should be a ``collaborative one''. As a consequence, talk of intense cooperation is thick in the air between America -- the nation with the deepest pocket on AIDS research -- and India -- the nation that is likely to be carrying the largest burden of AIDS in the next century.

According to a recent WHO estimate, India is already carrying an immense load of three-five million HIV-positive individuals. Further, based on sentinel surveys, even the Government of India now admits that about one in every 200 Indians is likely to be carrying the AIDS virus. The country is hurtling towards becoming the AIDS capital of the world. ``Vaccines are absolutely essential to interrupt this epidemic in developing countries and it is for that reason that the US is involved...andIndia should definitely take a leadership role in the development of a vaccine,'' says Anthony Fauci, a leading researcher on AIDS and director of the famous American laboratory the National Institute of Allergy and Infectious Diseases.

Till date, only about 25 candidate vaccines have moved into clinical trials, of which only three have advanced into clinical testing and only one has moved to large-scale human trials. This most advanced candidate vaccine has been developed by Vaxgen, a San Francisco-based private company. Two other candidate vaccines, also developed in the West, are going to be tested soon in Thailand and Uganda.

A strong feeling among experts is that the world needs more candidate vaccines and that other hot spots should be used to test these new vaccines as and when they are developed. India has all this while resisted all attempts made by developed countries to test an AIDS vaccine, citing ethical reasons for not allowing its population to be used as guinea pigs. But this hardlinepolicy is likely to be changed, with India now embarking on the development of an AIDS vaccine on its own, either fully indigenously or in collaboration.

At the end of the meeting that was attended by over 80 scientists, India decided to prepare a national HIV vaccine development programme which would juxtapose well with ongoing international efforts. India stands to gain strongly by participating in this international effort, for according to J. V.R. Prasad Rao, project director of the National AIDS Control Organisation (NACO) of India, ``we can take advantage by learning from the failures of others''.

On his part, Fauci -- who was leading the American delegation -- also seems keen on a joint effort in the search for an AIDS vaccine. ``Collaboration (with India) is an excellent idea and we are willing about accepting Indian collaborations in vaccine development...as it might lead to a quicker solution,'' he said. He also added that as and when a new candidate vaccine comes up which may take anywhere upto three-five years we can plan for testing it in India, but for that to happen, steps have to be initiated today in India and ``now the ball was in India's court''.

Since these are very early days, none of the participating parties was willing to speculate on the exact nature of the collaboration. Whether it would remain a scientist-to-scientist affair, a bilateral or a multilateral initiative or probably a mix-and-match collaboration. Seth Berkley, president of the non-profit scientific organisation the International Aids Vaccine Initiative (IAVI), New York, says a good collaboration will ``really cut time'', as there is a ``real emergency in India''. He adds that among the developing countries, apart from Brazil and China, India is the only one that has both the scientific base and the technological capability to commercially produce vaccines and India's non-participation ``will surely slow down'' the global effort to control AIDS.

The scientists may be in agreement, but finally it is the IndianGovernment that has to be first convinced, and that still seemed a little far way. ``Unless India is made a full and equal partner in the development of a vaccine and unless the candidate vaccine has been developed collaboratively, India will never allow the testing of a vaccine,'' says Manju Sharma, secretary of the Department of Biotechnology, Government of India. She adds this word of caution even while she admits that the only viable solution for India today is a vaccine, as the drug therapy is far too expensive, at around $18,000 a year. Sharma emphasises that India really needs a vaccine against the most prevalent strain C of the AIDS virus while most of the vaccines developed so far have been against the strain B of the virus, which is the most prevalent HIV strain in America and Europe. This is likely to change, with the IAVI announcing this week that it is investing $9.1 million for the development of vaccines for the strains most prevalent in developing countries.

There are other important issuesthat need to be resolved before an effective collaboration can get going and that includes touchy ethical problems like who is going to bear the exorbitant cost of treatment if some of the participants in the course of the trial were to contract AIDS. Ways of sharing the spoils and issues of intellectual property still pose a major stumbling block.

In conclusion, the Indian Council of Medical Research ``pledged support'' of its extensive resources and the NACO expressed its ``deep commitment'' towards the development of an AIDS vaccine. Predictably, the Americans were delighted. Expressing happiness over the deliberations, Carole Heilman, Deputy Director, Division of AIDS, NIAID, Bethesda, said she was ``very hopeful'' that an Indo-US collaboration may now really come through and was ``very thrilled'' that commitment for this new AIDS vaccine initiative had come from a ``high level'' in India.

(Pallava Bagla is India correspondent of Science)