Testing of Aids vaccine delayed

Large-scale testing of two combined Aids vaccines scheduled to begin in August has been postponed until the end of the year.

The trials, involving thousands of volunteers in Thailand, have been delayed as more time was needed to prepare for the unusually large project.

The five-year trial will use a combination of two vaccines, one from the French pharmaceutical company Aventis Pasteur and one from VaxGen of the United States.

They will be given to 16,000 uninfected volunteers aged between 20 and 30.

The Thai government has already trained 350 staff to administer the test, a collaboration between the Thai and US governments and the World Health Organisation.

It is the third phase of a trial, following laboratory testing and small-scale testing on humans.