As the13th International Aids Conference opens in South Africa, controversy has erupted among scientific experts over the existence of a causal link between the HIV virus and Aids. Yesterday, the "Durban Declaration" website was unveiled bearing a statement signed by more than 5,000 scientists and doctors affirming that the HIV virus causes Aids.
This unprecedented move is a clear broadside against some members of the panel of Aids experts set up by South Africa's president, Thabo Mbeki, who questioned the role of the virus. Disputes have been raging for more than a decade, but there is alarm among scientists because of President Mbeki's support for the dissidents.
Those dissidents are hopelessly outnumbered by the wave of signatories, who include a dozen Nobel prizewinners. What impact does this wrangle have on the public's view of science?
Alexander McCall Smith, professor of medical law at the University of Edinburgh and vice-chairman of the Human Genetics Commission, says: "There is a great deal of evidence that the public does not trust politicians and governments and that the public does not trust scientists, who are manifestly capable of using science for ends that the public finds alarming."
But Professor McCall Smith says studies also indicate that people still trust doctors, in spite of the "best efforts" of the press to discredit them.
"This potential for distrust - and resulting confusion - places a great burden on those who would interpret science to the public. Should scientific disputes, then, be aired publicly, or behind the closed doors of conferences and in the columns of academic journals?" Virginia Berridge, professor of history at the London School of Hygiene and Tropical Medicine, says: "This can be seen as part of the process whereby scientific orthodoxies are established. Sociologists of science would tell us this has always gone on, since science is not an absolute entity. But negotiations were not always considered public property and were hidden away as the prerogative of scientists. Now these processes are increasingly played out in the media spotlight."