In a year-long study, "The State of the World's Children", produced by the United Nations Children's Fund Unicef, researchers found that throughout the developing world HIV and Aids, armed conflict and deep poverty are reversing gains and endangering the survival, development and protection of millions of children.
Marjorie Newman Williams, deputy director of programme policy at Unicef, said that the world was not doing enough for children who, in many countries, had a life expectancy lower than 20 years ago.
"The public health programmes of immunisation and vaccination helped children enormously, and extended education has freed millions from harsh labour, but Aids and war are causing life expectancy in some countries to fall. In Botswana the life expectancy rose to 70, however a child born today can only expect to live until they are 40," she said.
The report shows that development assistance to the poorest nations has fallen dramatically and that many of the ambitious commitments made to children by the world's governments at the start of the Nineties have not been fulfilled. This has magnified the impact of entirely preventable calamities, according to Unicef.
The report shows that while the number of deaths among the under-fives continues to decline in developing countries as a whole, children's health in sub-Saharan Africa is still under severe threat. Some 4.1m children in the region aged under five died last year compared with 3.3m in 1980.