The jab that could smash HIV
9 February 2007, 10:51
When Glenda Gray and Eftyhia Vardas arrived at work on Friday, the world's attention was on them.
But for the two Johannesburg clinical scientists it's just another day in their ongoing search for an Aids vaccine.
For several years now they have been searching for the answer to the Aids epidemic - but have never been so close.
On Thursday, Gray and Vardas - and researchers in Cape Town, Klerksdorp, Pretoria and Durban - launched a four- and-a-half-year trial into the world's first most significant Aids vaccine candidate - MRKAd5.
And if they prove it does work, it would be a major boon in the fight against HIV and Aids.
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"It's the most promising Aids vaccine candidate the world has ever had. Very few others have gone this far into human development," said Gray, the principal investigator of the study.But for the two Johannesburg clinical scientists it's just another day in their ongoing search for an Aids vaccine.
For several years now they have been searching for the answer to the Aids epidemic - but have never been so close.
On Thursday, Gray and Vardas - and researchers in Cape Town, Klerksdorp, Pretoria and Durban - launched a four- and-a-half-year trial into the world's first most significant Aids vaccine candidate - MRKAd5.
And if they prove it does work, it would be a major boon in the fight against HIV and Aids.
Already, preliminary data from trials conducted in the US and South America suggest the vaccine is working against infection with the subtype B strain of the HI-virus that predominates in those areas.
Researchers in the US have found that MRKAd5 is safe and stimulated a cellular response in trial participants. The question now is whether it will work against the subtype C strain of the virus, prevalent in Southern and East Africa.
Gray and Vardas, both of Wits University's perinatal HIV research unit based at Soweto's Chris Hani-Baragwanath Hospital, aim to provide the answer.
"We are close but we are not there yet," Vardas said.
Developed by the American company Merck, the vaccine works by encouraging an immune response in an individual's body when exposed to HIV.
Conducted jointly by the South African Aids Vaccine Initiative and the HIV Vaccine Trial Network, this $35-million about R250-million) trial, called Phambili (moving forward), is aimed at determining whether that immune response is enough to prevent HIV infection and/or reduce the viral load of a person infected with the virus.
"Our best hope of ending the Aids epidemic is a safe and effective vaccine," said Dr Elias Zerhouni, director of the National Institutes of Health in the US, which supports the trial.
In the coming months, 3 000 healthy, HIV-negative male and female volunteers between the ages of 18 and 35 will be enrolled in the trial.
The double-blind trial involves an active vaccine candidate and a placebo - neither researchers nor volunteers will know which they are receiving.
Over the four-and-a-half years, participants will undergo nine clinic visits and three vaccine injections, and have blood drawn seven times.
In addition, each one will receive:
The trial procedure has been reviewed and approved by the Medicines Control Council, the department of agriculture and the US Food and Drug Administration.
Professor Anthony MBewu, the president of the Medical Research Council, said South Africa's conduct of the trial was a significant step forward in the search for a successful vaccine.
"It is the first trial to gauge the preliminary effectiveness of a vaccine, and the largest to be conducted in South Africa."
Vardas warned that because a different strain of the virus was prevalent here, there was no guarantee that the vaccine candidate would be effective.
"The scientific world is excited. We should also get excited but must be mindful that this is a scientific process fraught with challenges."
In addition, the MRKAd5 vaccine's particular vector - that element of any vaccine that is a modified "harmless" virus meant to stimulate a cellular immune response in the body - is a modified version of a virus called Adenovirus 5.
This is one of the viruses causing the common cold and most South Africans have been exposed to it early on in their lives.
Because it has been modified, it can't cause symptoms or disease.
- This article was originally published on page 3 of The Star on February 09, 2007
Pretoria
