It was meant to make sex safer by blocking HIV infection in the vagina. Instead, a trial of Ushercell – the first antiviral gel to be comprehensively tested in women – was halted on 31 January, after women using it were found to have higher rates of HIV than those using an inert gel.
Ushercell’s active ingredient, cellulose sulphate, had worked well in the lab and in animal studies. “Everyone has been speculating why, but no one can come up with the answer,” says Tim Farley, coordinator of the World Health Organization’s research on blocking sexually transmitted diseases.
Three other gels are…
