The number of Aids-related deaths and new cases of HIV infection in Switzerland dropped during the first six months of this year.
Most of the victims were men, according to preliminary figures from the Federal Health Office.
The number of deaths from Aids in Switzerland decreased from 22 during the first six months of 2004 to 17 during the same period this year.
The Health Office said all but one of the victims were men.
Amalio Telenti, an expert in HIV/Aids research and professor of medical virology at Lausanne University, warned against over-interpretation of the statistics.
"I think probably most of these numbers are not very meaningful," Telenti told swissinfo.
"We have now reached a very low level of death... and I think it's becoming increasingly difficult to assess these small fluctuations."
Last year the Swiss authorities recorded 80 Aids-related fatalities, bringing the total number of Aids victims since 1990 to 5,574.
The number of people diagnosed with Aids fell from 165 in the first six months of 2004 to 106 between January and June this year.
"There is no doubt that treatment and prevention programmes [in Switzerland] are working well," said Telenti, "but of course we still need to keep up the campaigns."
The number of new HIV cases dropped from 369 to 343 during the first six months of this year.
Two-thirds of the victims were men. About 45 per cent were infected through sexual intercourse with other men, while 79 per cent of the women tested positive for HIV as a result of intercourse with men.
About 12 per cent of new HIV infections - among men and women - were drug addicts, according to the Federal Health Office.
"These figures are nothing to get euphoric about," said Telenti, "because the moment you get euphoric people start to get complacent."
The latest statistics come as a four-day international conference on tackling HIV/Aids is underway in Rio de Janeiro, Brazil.
The meeting brings together thousands of health experts from more than 100 countries, including Switzerland.
Telenti, one of the keynote speakers at the conference, says the fight against HIV/Aids is likely to continue for decades.
"We are trying to correct a huge human problem... and in some parts of the world - such as China, Russia and the former Soviet states - we don't really have a clear idea of what is going on," he said.
"Things are going to get much worse before they get better. We have a whole generation of people who are going to pay a huge price."
First-half figures for 2005:
Aids-related deaths: 17
Aids cases: 106
HIV cases: 343
Acquired Immune Deficiency Syndrome (Aids) is caused by the Human Immunodeficiency Virus (HIV).
HIV damages the immune system and makes it harder for the body to fight off infections. It is mainly transmitted through body fluids.
Medication can slow down the development of HIV into Aids. But as yet there is no cure for the disease.