AS THE YEAR ends, the United Nations Children's Fund estimates that 150 million of the world's children do not receive adequate health care. It is a discouraging figure but not one that must be accepted as chronic or permanent. Public health officials know what has to be done. What is needed is the commitment of political leaders and, as always, the resources such a strenuous effort would require.

Last September at a summit organized by the U.N. agency, the leaders of 71 nations pledged to work toward 20 specific goals, many directed at improving the health of children. The setting and acceptance of goals is itself a beginning. This month, a particular mark was reached. For 10 years, health planners have been working toward universal immunization of children under 5. In 1981 only 15 percent of the children in the developing world were being immunized, and now that figure is 80 percent -- right on schedule. Though the effort went on in many places, the most gratifying results were achieved in countries that mobilized resources, undertook public education campaigns and had the direct involvement of the political leaders.

Other news from UNICEF is that infant mortality is declining, worldwide, into that zone where the rate of population growth also begins to fall. In the United States, 12 young children die for every 1,000 born. The comparable figure in Mozambique is 297. It is estimated that when infant mortality falls below 140 per 1,000, parents become confident that their children will survive and voluntarily start to limit family size. UNICEF's goal is to reduce infant mortality to less than 70 per 1,000 by the end of the decade, which is expected to have the beneficial side effect of reducing the overall rate of population growth.

Even if population programs are successful, more children will be born in the 1990s than in any decade in history. Before the century ends, UNICEF believes these further child health goals can be achieved: the elimination of polio, neonatal tetanus and guinea worm disease, a 90 percent reduction in measles, an 85 percent rate of immunization among one-year-olds, a 50 percent cut in childhood diarrhea deaths and in malnutrition among 5-year-olds, and a 33 percent reduction in deaths from respiratory infection and in infant mortality. That is an ambitious agenda, but it is achievable. The promises made by world leaders last September must be kept.