2006年VOA标准英语-Research Into Anti-HIV Microbicides Gather（在线收听）

By Delia Robertson
Johannesburg
25 April 2006

In South Africa a conference on the development of microbicides to combat the spread of HIV, the virus that causes AIDS, is underway.    
 
  
  
More than 1300 scientists from across the globe are gathered in Cape Town to review progress in research into microbicides, products that would be used primarily by women to prevent infection with HIV, the virus that causes AIDS.  It is also hoped that they will be effective in preventing infections between males.

Microbicides are compounds that contain molecular ingredients shown in the laboratory and in animal studies to be active against HIV at the cellular level.  Some may also be anti-spermicidal and thus also serve the purpose of contraception.

Research into microbicides began when it became clear that in sub-Saharan Africa in particular, disproportionately high numbers of women were becoming infected with HIV.  Research showed that women in poor, underdeveloped communities and those in male dominated societies have limited sexual choices and are often unable to negotiate the use of condoms with their partners.

Professor Helen Rees of the University of the Witwatersrand, says that scientists realized that it was important to develop products that would benefit women in such circumstances.

"So, it is very important that we try and find alternative HIV prevention methods, in addition to condoms- - male and female condoms and the other technologies that we are trying to introduce," she says. "It's very important that we try and identify some that truly could be a female-controlled method and for women who can't negotiate or discuss this with a partner, something that could also be concealed from a male partner."

There are currently five clinical trials underway testing products that have demonstrated anti-HIV activity in the laboratory and in animal tests and which have also proven to be safe in animals and humans.  The trials involve thousands of non-infected women, mostly in southern Africa, who have also been given condoms and intensively counseled about using them.  

Rees, who is one of the conveners of the Cape Town conference, says that all of the trial products are vaginally-administered in pre-filled applicators and must be used within one hour of intercourse.

"The other thing though, is that further down the line, if we can find an effective microbicide we would also want to get a product that isn't so coitally dependent - that it isn't something that has to be administered just before you have sex;  something perhaps that could be administered and would stick around for 24 hours, or even longer, a week, or even longer," she says.

Rees also notes parallel research is also underway to find inexpensive application methods that could be easily manufactured.

Research into microbicides, which may also one day be used to combat other sexually transmitted infections, began just 15 years ago.  But Rees tells VOA that it is fast gathering momentum.

"There is this sense of optimism," Rees says. "There is also a sense that the science in the field is now really expanding and moving and its become a field that was previously perhaps something that wasn't attracting a lot of attention and now people are saying, hang on this is really a possibility and these could be literally lifesaving technologies, if we can develop them."

The first results from the current trials will be available in 2008.  Researchers say it is unlikely that a usable microbicide will be available this decade.