UNITED NATIONS (Reuters) Nov 20 - Vaccinations have prevented millions of deaths around the world but children in wealthy nations are getting the lion's share of the shots--and the benefits, the United Nations said on Wednesday.

While young people in rich countries have access to the latest and costliest vaccines available, just 50% of children in sub-Saharan Africa are immunized during their first year of life against common diseases like tuberculosis, measles, tetanus and whooping cough, three UN agencies said in a joint report.

In poor and isolated parts of some developing nations, vaccines reach fewer than 1 in 20 children, said the report by the World Health Organization, the World Bank and the UN Children's Fund.

"Immunization, as powerful and successful as it is, has yet to reach its enormous potential," the report said. "The right to protection from preventable diseases is the right of every child and it is well within our collective capacity to realize that right."

A quarter of the world's children lack protection from common preventable diseases, according to the report. Nearly 3 million people--2 million of them children--die every year from those diseases, it said.

While vaccines for diseases like meningitis and pneumonia are widely available in rich nations, children in developing countries are dying from these same diseases, it found.

According to the report, rich nations annually provide $1.56 billion in aid to immunization programs. An extra $250 million a year would cover the cost of basic vaccines for at least another 10 million children, it said. A further $100 million would cover the cost of newer vaccines for these children, including those protecting against hepatitis B and Haemophilus influenzae type B (Hib).

Hepatitis B now causes 520,000 deaths a year worldwide while Hib kills 450,000 children in developing countries, the report said.

Developing nations, which currently spend as little as $6 a year per person on health including immunizations, also need to increase their spending, it said.

The low levels of protection against diseases that ravage primarily the developing world are also having a significant impact on vaccine research, the study found.

Drug companies find they have little incentive to invest in vaccines for diseases that attack mostly the poor, such as Shigella dysentery, dengue, Japanese encephalitis, leishmaniasis, schistosomiasis and cholera, the report said.

It called on pharmaceutical firms--with help from wealthy governments--to redouble their efforts to develop vaccines against malaria, which kills about one million people each year, and tuberculosis, which killed 1.7 million people in 2000.

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