In the Andaman Islands, a helicopter delivering food and water to survivors of December's tsunami briefly found itself under assault from the arrows of xenophobic Sentinelese tribesmen. Outsiders feared the flooding might finish the already endangered societies native to the islands. But the Sentinelese attack was welcome proof that at least some of them were still alive.

In these first weeks after the tsunami, with the death toll still climbing past 225,000, good news has been redefined as the absence of bad. Reports exult over selected survivors--a baby floating on a mattress, an injured model, a pregnant woman rescued from the open sea--and many of us are grateful for word of friends and family who are safe. But for every one of them, thousands of others unknown to us were lost. Meanwhile the ranks of the injured and homeless stretch from Indonesia to Africa, and the questions and concerns that their plight raises are not confined to that side of the planet.

The outpouring of emergency aid will be a great help to the ravaged countries, but disaster relief is an inadequate, expensive substitute for more timely improvements to their infrastructures. The most obvious example was that Indian Ocean nations lacked a tsunami-warning system like the one in the Pacific, but that omission may be forgivable. Tsunamis are rare in the Indian Ocean. Undersea sensors can cost a quarter of a million dollars apiece and have steep maintenance costs. India, Sri Lanka and the other wave-torn nations had far more urgent spending priorities. (In January a chastened India announced belatedly that it would invest $29 million on tsunami detectors after all.)

The real humanitarian fiasco is not the inadequate preparation of these nations, and many others, for freakish catastrophes. It is their inadequate preparation for the day-to-day horrors that routinely slaughter their populations. Millions of people die annually from malaria and AIDS--more than the equivalent of a tsunami a month. Lack of clean water in parts of Africa promotes disease and fuels civil conflicts. Poor countries face chronic crises so dire that the world's sensibilities have been numbed to them.

The U.S. and other industrial nations need to be more forthcoming with aid outside of calamitous times. In 2000, as part of the Millennium Development Goals program, the United Nations General Assembly embraced the target that rich states would pledge 0.7 percent of their national incomes to development assistance. Few countries (and the U.S. is not among them) are living up to that promise. Making matters worse, countries sending tsunami aid now will probably subtract those donations from their development aid budgets. In mid-January the Millennium program issued a new recommendation that countries donate just 0.5 percent, a retrenchment from the old goal but still twice the average now in practice. Even that figure has been criticized as unrealistic.

Sound public health policy needs more than fitful, reactive generosity. When the media focus our attention on the aftermath of tsunamis and other disasters, it is easy to empty our wallets for the agonized sufferers. But we need to do more on the fairest days for the billions out of sight and out of mind, whose survival depends on more days without bad news.