Controversy is surrounding a phase II clinical trial of an HIV vaccine that began in Italy this month.

Led by Barbara Ensoli of the ISS in Rome, Italy's major health research laboratory, the trial is testing a vaccine based on a protein called Tat, which is involved in the replication of HIV.

But critics, including HIV co-discoverer Robert Gallo of the University of Maryland School of Medicine in Baltimore, argue that the scientific basis for Ensoli's vaccine is weak. They note that Tat has proved ineffective in animal models in other labs.

Critics in Italy are also complaining that Ensoli's phase I trial was insubstantial, and that the government has allocated a disproportionate amount of money — €21 million (US$33 million) over three years — to the work.

Ensoli says that she expects the phase II trial to be looked on favourably by an ISS external committee of experts that will meet this winter.