Scientists and sexual health charities have warned that the case of a man who appears to have been cured of HIV by a bone marrow transplant from a donor who had a genetic resistance to the virus does not represent a major breakthrough.

Around one in 1,000 people in the US and Europe have the genetic mutation, which prevents the HIV virus from attaching itself to cells.

Professor Rodolf Tauber from the Charite clinic in Berlin treated the man for leukaemia.

“This is an interesting case for research,” he said.

“But to promise to millions of people infected with HIV that there is hope of a cure would not be right.”

In the twenty months since the transplant the patient, a 42 year old American, has shown no sign of leukaemia or HIV.

“People with HIV always live in hope of seeing a big breakthrough in research but unfortunately it’s not time to crack open the champagne just yet,” said Paul Ward, deputy chief executive of sexual health charity Terrence Higgins Trust.

“This case gives us something to explore in future studies but it’s certainly not a quick fix as gene therapy is complex and expensive.

“For those without the virus, condoms are still the most effective way of protecting yourself from HIV. With no cure in sight, prevention should be our number one priority.”