GENEVA, April 3, 2008 (AFP) - More than two million children worldwide were living with the HIV virus in 2007, most of whom were infected before they were born, a joint study by United Nations humanitarian organisations said Thursday.

Some 290,000 children under the age of 15 died of AIDS last year and 12.1 million children in sub-Saharan Africa lost one or both parents to the disease, according to the "Children and AIDS" report by the World Health Organisation, UNICEF and UNAIDS.

"Today's children and young people have never known a world free of AIDS," said UNICEF executive director Ann Veneman.

"Children must be at the heart of the global AIDS agenda," she urged.

The report highlighted four areas crucial to tackling the epidemic: preventing HIV transmission from mothers to children; providing paediatric treatment; preventing infection among adolescents and young people; and protecting and supporting children affected by AIDS.

While some progress has been made in all these areas, the report found that significant challenges remain.

For example, 21 countries including Botswana, Brazil, Rwanda, South Africa and Thailand are now on track to reach 80 percent coverage to prevent mother-to-child HIV transmission by 2010, up from only 11 countries in 2005.

The proportion of HIV-positive pregnant women receiving retroviral drugs to reduce the risk of transmitting the virus to their children rose by 60 percent from 2005 to 2006 -- although this still means that less than a quarter (23 percent) of all such women get retrovirals.

The report also said that the number of HIV-positive children in low- and middle-income countries getting retrovirals rose 70 percent over the same period to 127,000 from 75,000.

"We must provide antiretroviral treatment for women who require it... to achieve this, health systems and their most precious component, the health care workforce, must be strengthened," said Kevin DeCock, director of the WHO's HIV division.

The report also welcomed an increase in funds to tackle the disease, even if funding gaps persist.

"Governments and donors alike are allocating more resources to prevention, treatment and protection efforts," it said.

In 2007, some 10 billion dollars (6.4 billion euros) were available to combat AIDS, up from 6.1 billion dollars the previous year.