Maybe no one believes that government can do good works. But some very cheering and important news received relatively little notice the other day: Amercians, in the mass, are healthier than ever.

A measure of this is that the infant mortality rate has been greatly reduced. The inexcusable black-white differential in newborn deaths, though still substantial, is at last narrowing, and at the current national rate of 14 deaths per 1,000 live births, the United States is no longer the laggard of the major industrial countries.

Meanwhile, at the other end of the life scale, Americans are living longer than ever, with life expectancy at birth at a historic peak of 73.3 years. It was 69.7 just 20 years ago. The more revealing figure for seniority, however, is that of remaining expectancy at age 65, which is up from 14.3 in 1960 to nearly 16.5 last year.

What's the source of improvement?

Public health managers, such as the outgoing surgeon general, Julius Richmond, tend to be professionally modest in identifying the causes, pointing out that there's no certain way to calculate all the important life-lengthening and life-limiting factors in our mobile, high-technology society. But, with due respect for the scholarly caution of the health professions, it's necessary to note that over the past 15 years -- the period of some of the greatest gains in health -- a government-backed spread-the-health offensive has revolutionized health care and nutrition among the neediest segments of the population. And, for all the population, efforts initiated and backed by Washington have produced miracles of change in health awareness and interest in self-care.

Thus, contrary to popular impression, the poor today don't get less medical care than the rich; they usually avail themselves of more, though it's generally less accessible and less dignified. The wherewithal for lower-income patients' being ahead of the rich and even with the middle class in doctor visits per year is, of course, in public expenditures for health care. In 1965, public money paid 25 percent of our national health bill; today it's over 40 percent.

While the food stamp program is popularly depicted as a hotbed of fraud and deceit, what has generally gone unnoticed is that food stamps have come close to abolishing malnutrition in this country. Public health officials do not lack for problems to worry about, but gross malnutrition now ranks low as a health problem. This triumph of government intervention has attracted little favorable attention, but it ought to.

So, too, should various other government intrusions into health affairs. A forceful, nationwide child immunization program has practically eliminated measles. And declines in dietary fat intake and tobacco consumption have also coincided with government propaganda drives against these products. The number of government-supported health clinics for the poor -- situated in otherwise medically deserted ghetto and rural areas -- has tripled, to about 900, in the past four years.

Curiously, it's the Love Canals, radiation scares and gumshoe quests for Medicaid cheats that dominate the popular accounts of the American health scene. The historic fact that something out there is working extraordinarily well in behalf of American health -- and that the federal government obviously has a lot to do with it -- goes largely unnoticed.