A YEAR and a half ago, the United States, after an emotional national and international debate, cast the sole dissenting vote in the United Nations against a World Health Organization Code limiting the marketing of infant formula in developing countries. Despite the U.S. vote, the coalition promoting the code has since won significant victories. The major international marketer of infant formula, the Nestl,e Co., has begun a voluntary effort to put the code into effect. Although the anti-formula activists claim that code violations still occur, such as sample handouts in hospitals, only 30 cases are now cited rather than the hundreds previously alleged.

There is obvious good in preventing aggressive marketing tactics that might persuade women who shouldn't or needn't switch to formula to do so. Not only is formula expensive, but, when overdiluted or mixed with polluted water, it can pose a severe health hazard to babies. There is concern, however, among health professionals and researchers -- including the American Academy of Pediatrics -- that the role of infant formula as a threat to infants in developing nations has been blown out of proportion. They also fear that pointing to formula as a major threat distracts attention from other factors -- unsanitary water supplies, undernourished mothers and insufficient spacing of children -- that are known to be far more important determinants of infant mortality.

Upon closer inspection, the data linking formula marketing and infant mortality turn out to be sketchy at best. Links between duration of breast-feeding and subsequent infant survival, for example, probably have much more to do with the initial health status of the mother and child than with any presumed switch to formula. Nor is there hard evidence of a major decline in breast-feeding among poor women in most underdeveloped countries. Common sense suggests that the expense of formula alone would prevent its widespread use among the very poor. Where a substantial decline in breast-feeding has been documented, in Taiwan and Malaysia, there has actually been a remarkable drop in infant mortality -- both factors being related to rising incomes, improved living standards and more women working outside the home.

The anti-formula crusade has given important attention to the continuing problem of high infant mortality in many countries. But international health policy needs a broader perspective. Fear of abuse should not block the availability of high-quality formula where it is needed. Nor should it distract attention from the fact that improving sanitation, education and general living conditions is the surest, and perhaps only, way to make substantial reductions in infant mortality.