The recently developed Tanzanian Aids vaccine is lined up for ‘tabling’ before a week-long conference of over 1,000 top world scientists that opened in Paris yesterday.

In the first case of its kind in quarter a century, items on the agenda of the fifth international conference on Aids include deliberations on two potential vaccines for the pandemic.

The conference started amid optimism that a vaccine conducted on a small scale in Tanzania would provide better protection than the much-touted Thai formula.

But despite suggestions that protection offered by the Thai vaccine was too low to be considered a breakthrough, the experimental HIV vaccine is expected to take centre stage as scientists seek to analyse it for the first time in the public arena.

The vaccine was developed in partnership with the US Army and Thai government and is reported to have cut HIV infection by 31 per cent.

Prof Britta Wahren of Sweden’s Karolinska Institute said earlier yesterday that the Tanzanian vaccine, which was jointly developed by the Muhimbili University of Health and Allied Sciences and the government of Sweden, would be screened for its safety as well as how the body’s immune system reacted to it.

“We hope that our vaccine could increase protection to 50 per cent. The vaccine includes more strains of the virus – from Europe, Africa, the United States and Asia – and therefore provides a broader protection,” AFP quoted him as saying.

Scientists said they would comment on the Tanzanian vaccine only after seeing the results of the screening, but Wahren said the results they had until now were “so encouraging that our researchers are keen to carry out Phase III testing”.

Prof Fred Mhalu, the trials’ principal investigator, said the Thailand trials involved more than 16,000 healthy volunteers in a Phase III study and were done to test if a drug known as RV144 reduced the chances of being infected.

“But tests on the Tanzanian vaccine were aimed at finding out how the vaccine responded to the body’s ability to stimulate the immune system,” he explained.

He added that the vaccine had proven its ability to stimulate the immune system by 100 per cent, but warned that it would take a long time before a vaccine ready for use was found.

“You need a lot of money to conduct an efficacy study in terms of building capacity and other things. This has been our very first time to conduct such trials,” Prof Mhalu said in a telephone interview with The Guardian.

He played down the possibility of the Tanzanian vaccine generating too much debate at the conference because it was presented in poster form and not in oral form.

“The reason we decided to take the vaccine to the Paris conference was that we badly wanted to share experience in scientific innovation and enhance collaboration with other experts,” observed the professor.

Scientists say it is still unclear why the Thai vaccine, which comprises a combination of two previously tested vaccine candidates, had worked.

Prof Mhalu predicted that this will likely touch off heated debate at the conference because the two-vaccine drug was used as part of a “prime-boost” strategy, in which the first drug primes the immune system to attack HIV and the second strengthens the response.

“A lot of debate is going to be on that but we need more than five or ten years before a real vaccine is eventually found,” he said.

He added that the Muhimbili vaccine research was conducted with public funding and the main challenge ahead was how to attract pharmaceutical companies to invest money into future vaccine trials.

The professor said drug companies were usually interested only in products with a promising future “and it is only after they are assured that they can commit finance and other support”.

He warned the public against negligence and unsafe behaviour “wrongly convinced that a sure Aids vaccine is soon to be found”.

Tanzania’s HIV/Aids and Malaria Indicator Survey for 2007/08 shows that HIV/Aids infection and prevalence have dropped to 5.7 per cent in the year under review from 7.0 per cent in 2003/2004.

The survey has found that women recorded a prevalence of 6.6 per cent as against 4.4 percent for men. A total of 1.3 million people are estimated to be living with HIV/Aids in Tanzania.

The Tanzanian vaccine was tested on 60 healthy policemen in the country in what is called Phase I trial. That is the stage when a vaccine is tested on a very small group of volunteers to assess its safety. A Phase III trial is a large-scale investigation among thousands of people and focuses especially on effectiveness.

Other partners that took part in the Muhimbili study include the EU, US Army, University of Munich in Germany and Cape Town University.

SOURCE: THE GUARDIAN