Young children and certain other people with the AIDS virus should be started on medicines as soon as they are diagnosed, the World Health Organization says in new guidelines that also recommend earlier treatment for adults.

The advice will have the most impact in Africa, where nearly 70 % of people with HIV live. Many rich countries already advocate early treatment. WHO's new guidelines were released yesterday at the International AIDS Society meeting in Kuala Lumpur, Malaysia.

About 34 million people worldwide have HIV, the virus that causes AIDS. HIV attacks key infection-fighting cells of the immune system known as T-cells. When that count drops to 200, people are considered to have AIDS. In the past, WHO recommended countries start treating people with HIV when their T-cell count fell to 350; a normal count is between 500 and 1,600.

The new recommendations say to treat earlier, when the T-cell count hits 500.

In addition to children under 5, WHO says several other groups should also get AIDS drugs as soon as they're diagnosed with HIV: pregnant and breast-feeding women, people whose partners are uninfected and those who also have tuberculosis or hepatitis B.

The new guidelines mean an additional 9 million people in developing countries will now be eligible for treatment. At the moment, only about 60 % of people who need the life-saving drugs are getting them.

The new guidelines also mean the total global spending on AIDS — about €20 billion a year — will rise by about 10 %, according to Gottfried Hirnschall, director of WHO's HIV department. Given the ongoing financial crisis, it's unclear how willing donors will be to pitch in for even more AIDS treatments.

Hirnschall said the cheapest course of the drugs costs €100 per person every year under programs that have negotiated prices for poor countries, but the price can be much higher elsewhere. WHO's recommended treatment is a single pill that combines three powerful drugs taken once daily.

WHO's new guidelines are based largely on recent studies suggesting people with HIV who start treatment before their immune systems weaken live longer.

Several studies have also hinted that starting therapy early dramatically cuts down the chances an infected person will pass on the virus to a sexual partner.

If all countries start treating people with HIV in line with the new recommendations, WHO estimates 3 million lives could be saved and 3.5 million new infections could be avoided in the next decade.