美国国家过敏症和传染病研究所专家14日表示，历经数十年的努力，全球卫生机构开始在艾滋病疫苗研制方面取得“重大进展”，使科学家对这类疫苗投放市场的信心倍增。

Global health authorities are finally beginning to make significant advances towards a vaccine¹（疫苗） against AIDS, a top US researcher says.

'Up to a few years ago, even though we have been trying for a couple of decades to develop a vaccine, unsuccessfully, we have not even had a small clue that we were going in the right direction,' Fauci told AFP.

But two key events that have taken place in the past few years have changed that and led to 'significant advances in the development of a vaccine', said Fauci, who is head of the National Institute for Allergy² and Infectious Disease (NIAID).

The first of those key turning-point events was a clinical trial of an HIV/AIDS vaccine, which was conducted in 2009 in Thailand on 16,000 people.

'The results showed a small to modest positive effect on the acquisition（获得物） of HIV - not good enough to be able to distribute a vaccine, but good enough to tell us that it was a conceptual advance that at least makes us feel now that a vaccine is possible,' Fauci said.

Then, last week, scientists at NIAID published a paper in the journal Science about research that had helped them to identify two antibodies in an HIV-positive individual, which, when put together 'block 90 per cent' of HIV strains, Fauci said.

'What that is telling us is that you can identify the portion of the virus that you would like to use as a vaccine, because we know that when the antibodies bind³ to that portion, it knocks down the virus,' he said.

The next step will be to try to inject that part of the virus into an individual to produce a protective response against HIV infection, said Fauci in an interview with AFP days before the 18th international conference on AIDS, to be held in Vienna, Austria.

The Thai study and the report in Science have left scientists feeling 'much more confident that ultimately we will have a vaccine' against HIV/AIDS, although it was still impossible to say exactly when that would be, said Fauci.

An AIDS vaccine was probably several years away, which means that in the meantime, the fight against HIV/AIDS must continue to focus on prevention and use tried and true tactics（策略，战术） such as condom distribution, male circumcision（包皮环割术） , blocking mother-to-baby transmission and offering syringe（注射器） exchange programs, he said.

Ways have to be found, too, to improve access to these preventive measures, especially in developing countries where only 20 per cent of 'populations who would benefit' actually have access to them, he added.

Along with improving access to the preventive methods, Fauci urged global health authorities and governments to continue to work to develop other forms of prevention, such as microbicides.

And he recommended 'treating as many people as we possibly can because we know that when you treat more people, you lessen⁴ the probability that they would infect other people.

'You could almost have what we call treatment as a form of prevention,' until a vaccine is finally developed, said Fauci.