The United Nations children's agency, UNICEF, has said that while there have been advances in children's health in recent years, millions of young people still die from diseases that could easily be prevented.

In 1990, at the World summit on Children, nations around the world agreed to work to improve the health of their children. The head of UNICEF, Carol Bellamy, said in the years since that summit infant mortality rates have been reduced by 30 to 40 percent.

Ms. Bellamy has welcomed this improvement but said many children still die each year from illnesses that can be prevented, and that is one of the issues that the U.N. special session will address. "It is estimated that about 11 million children die worldwide from totally preventable causes that do not cost a huge amount of money to prevent - such as immunization campaigns, better water, better sanitation. So this Special Session on Children is anchored first in recognizing there is still unfinished business from the past," Ms. Bellamy said.

UNICEF said that 7 out of 10 childhood deaths in developing countries result mainly from pneumonia, diarrhea, malaria, malnutrition and measles. It has said of all the vaccine preventable diseases, measles is the most deadly, killing more than three-quarters of a million children every year.

UNICEF reports notable success in reducing - and in some cases nearly eliminating - several diseases. UNICEF spokesman Marc Vergara said more than 175 countries are now polio-free.

"It has come down to such a point that we can talk about near total eradication. Although there are still some 10 countries left on the list (of countries with polio), we are getting there," Mr. Vergara said.

He said another success has been the campaign against neonatal tetanus an often fatal disease caused by bacteria that live in the soil. Ten years ago, 470,000 children died of the disease, but the death toll has been steadily decreasing in recent years. According to Mr. Vergara, Malawi, Zimbabwe and Namibia are on the verge of totally eradicating neonatal tetanus.

UNICEF officials said that the success stories are the direct result of immunization efforts. They credit these efforts with saving the lives of three million children every year.

But agency officials have said many young people such as those in areas of conflict - are still beyond their reach because they cannot be accessed by health workers.

Mr. Vergara said that while progress is being made in saving children, giving birth in the developing world is still far more dangerous than in the developed world.

"One of the worrying trends is that there is no progress in maternal mortality rates. What this means in practical terms is that nearly one-half million women die every year - 515,000 to be precise - from complications due to pregnancy and childbirth," he said.

Mr. Vergara said good obstetric care, the presence of birth attendants, and simply being able to reach health centers would save the lives of many women.

UNICEF chief Carol Bellamy said that while the agency will maintain its focus on reducing child and maternal mortality rates, it must also address other issues.

"For example, the effect of war on children. Today the victims of war are not military, they are largely civilian women and children. The terrible impact of the pandemic of HIV-AIDs on children, infecting children, killing children's parents so that they become orphans, babies infected at birth. So HIV-AIDs has to be confronted. The issue of exploitation, of trafficking. The issue of child labor," Ms. Bellamy said.

The UNICEF chief said although great strides have been made, much more needs to be done to protect children around the world.