Hope rekindled as scientists announce possible Aids vaccine

By Elizabeth Mwai and Maore Ithula

Scientists have announced a breakthrough in the search for an Aids vaccine after decades of trials.

The vaccine attempt by the US army and Thai Government, which Kenya has hailed as a first of its kind, has successfully reduced the risk of HIV transmission by 31 per cent.

The Kenya Aids Vaccine Initiative director Omu Anzala yesterday said this achievement had not been attained, and now gives scientists a benchmark against which to advance their research.

"This is what we have been working on. This is proof enough that yes, we can," said Anzala.

In an interview with The Standard Anzala said at the success rate of 31 per cent, the next step is for scientists to design the next generations of vaccines that are more effective.

First injection

The seven-year-old landmark study on HIV-negative volunteers tested a two-vaccine combination in a "prime boost approach" where the first injection primes the immune systems to attack HIV and the second strengthens the response.

The vaccine is a combination of two earlier experimental vaccines that never worked.

These vaccines are Alvac from Sanofi Pasteur, and Aidsvax, originally developed by VaxGen Inc and now held by Glibal Solutions for Infectious Diseases, a non-profit organisation founded by some former VaxGen employees.

According to a report published by the BBC and The Daily Telegraph Online, the vaccine was given to 16,000 people in Thailand. Samples were drawn from men and women of between ages 18 and 30, who are classified as the most sexually active group.

Researchers found that it reduced the risk of contracting HIV by about a third. Half of the volunteers were given the vaccine, while the other half were given a placebo and all were counseled on HIV/Aids prevention.

The results found that the chances of contracting HIV were 31.2 per cent less for those who had taken the vaccine.

It is also the first time in human trials that a vaccine has stopped the virus, which infects 7,500 worldwide every day.

The National Aids and STD Control Programme Director Nicholas Muraguri said this breakthrough could help avert the rate at which new infections were occurring.

According to scientific evidence, a vaccine that is 50 per cent efficacious given to 30 per cent of a population would help cut the rate of new infection by 25 per cent.

"In Kenya, we have tried the use of Abstinence, Be Faithful, Condoms (ABC) campaign and male circumcision, but the spread of the virus continues, hence a vaccine would be very important," said Dr Muraguri.

In addition he said the findings though modest would help accelerate the search for a stronger vaccine.

First evidence

Colonel Jerome Kim, who helped lead the study for the US Army said: "It is the first evidence that we could have a safe and effective preventive vaccine."

The Thailand Ministry of Public Health conducted the study, which used strains of HIV common in Thailand. Scientists stressed it is not clear whether the vaccine would work against other strains in the United States, Africa or elsewhere.

The Director of Public Health Shahnaaz Sharif said although a 31 per cent success rate is remarkable the country would adopt such a vaccine if it passes the 65 per cent-mark.

But Sharif says before such a vaccine is introduced the ministry would have to consult the World Health Organisation and the Centres for Disease Control, among other professional research institutions.

But he is critical of Kenyans who do not take their children for vaccination, as demonstrated by the levels of immunisation coverage.

"Look at the measles scenario: We have advertised so much about the danger but parents are not bringing their children to be immunised," said Sharif.

The International Aids Vaccine Initiative President and CEO Seth Berkley, told The Standard they were excited at the announcement of the breakthrough.