Health officials are considering a radical shift in the war against HIV and Aids that would see everyone tested for the virus and put on a lifetime course of drugs if they are found to be positive.

The strategy, which would involve testing most of the world's population for HIV, aims to reduce the transmission of the virus that causes Aids to a level at which it dies out completely over the next 40 years.

Brian Williams, professor of epidemiology at the South African Centre for Epidemiological Modelling and Analysis in Stellenbosch, said that transmission of HIV could effectively be halted within five years with the use of antiretroviral drugs (ARVs).

"The epidemic of HIV is really one of the worst plagues of human history," Williams told the American Association for the Advancement of Science meeting in San Diego.

"I hope we can get to the starting line in one to two years and get complete coverage of patients in five years. Maybe that's being optimistic, but we're facing Armageddon."

Major trials of the strategy are planned in Africa and the United States and will feed into a final decision on whether to adopt the measure as public health policy in the next two years.

The move follows research that shows blanket prescribing of ARVs could stop HIV transmission and halve cases of Aids-related tuberculosis within 10 years.

A Person with HIV infects five to 10 people with the syndrome
More than 30-million people are infected with HIV globally and two million die of the syndrome each year. While ARVs have been a huge success in preventing the virus from causing full-blown Aids, scientists estimate only 12% of those living with the syndrome receive the drugs.

The syndrome is overwhelmingly prevalent in sub-Saharan Africa, which accounts for a quarter of all HIV/Aids cases globally. Half of these are in South Africa.

In general epidemics, a person with HIV infects between five to 10 others before succumbing to complications of Aids. Treating patients with ARVs within a year of becoming infected can reduce transmission tenfold, enough to cause the epidemic to die out.

In the trials, people will be offered HIV tests once a year, either as routine when they visit their GP, or through mobile clinics in more remote regions. Those testing positive will be put on a lifetime course of ARVs.

"Over the past 25 years we have saved the lives of probably two to three million people using antiretroviral drugs, but almost nothing we have done has had any impact on transmission of the disease," Williams said. "We have stopped people dying but we haven't stopped the epidemic."

We're killing half a million young adults every year
If patients take ARVs when they should, the amount of virus in their bodies can fall by 10 000 times, to a level at which they are extremely unlikely to pass the virus on.

"The question is, can we use these drugs not only to keep people alive, but also to stop transmission and I believe that we can. We could effectively stop transmission of HIV in five years." Scientists estimate that the cost of implementing the strategy in South Africa alone will be R24-billion- R30-billion a year.

Sub-Saharan Africa has seen a dramatic rise in cases of tuberculosis among HIV patients, who are also susceptible to other infections because their immune systems are weakened.

"If you factor in all of the costs, in my opinion, doing this would be cost saving from day one, because the cost of the drugs would be more than balanced by the cost of treating people for all of these other diseases and then letting them die," Williams said.

"We're killing probably half a million young adults every year in the prime of their life just at the point where they should be contributing to society and the cost of that to society is enormous," he added. "The only thing that's more expensive than doing this is not doing this."

HIV patients in southern Africa are more likely to take ARVs when they should than people living in developed countries, according to health officials. The finding gives doctors hope that the blanket administering of drugs might suppress the virus enough that it dies out naturally.

Last year, scientists reported marginal success of a HIV vaccine following a large scale trial in Thailand. The vaccine benefited only 31% of those who received it. A vaccine is generally regarded as worthwhile if it protects more than 70% of those treated