AS A QUESTION of public ethics, the vaccine injuries -- and the absence of reliable and orderly compensation for them -- continue to be deeply troubling. Vaccines against infectious diseases are one of science's greatest gifts, contributing enormously to lower death rates among, especially, small children. But in rare cases a vaccine can injure a child, sometimes fatally. Those few unluckily susceptible children and their families bear the cost of better health for the population as a whole. They are clearly entitled to compensation, and yet this country has not so far been able to figure out a rational way to provide it.

Currently, compensation is left to lawsuits -- an erratic and uncertain process that forces families to go through years of litigation, while driving most of the drug manufacturers out of vaccine production. A dose of the vaccine for diphtheria, whooping cough and tetanus cost, five years ago, 68 cents. Today it costs $8.92, of which more than $5 goes into the manufacturer's reserve against product liability judgments. Only two companies make that vaccine in this country; only one makes the polio vaccine.

A year ago Congress passed legislation that established, at least in principle, the right solution. It set up a trust fund to compensate injured children. But that system hasn't gone into effect because the tax to feed the trust fund has never been enacted. This year the House has produced a tax and rolled it into the gigantic budget reconciliation bill. But in order to get the tax passed, its authors attached limits on compensation to hold the costs down to their predictions. These limits raise serious issues of equity.

Dissatisfied Parents Together, representing parents of injured children, points out that the new tax would pay only for future injuries, not for those suffered in the past. The bill offers certain modest benefits for past injuries, to be paid out of appropriated funds. But, as the parents observe, the chance of getting an appropriation in the current climate is poor. The bill restricts future compensation to 150 children a year, and the number of injuries is higher than that. To the parents, that's unfair. And to the vaccine manufacturers, it means that the risks of product liability suits will continue.

Those are substantial objections, and yet, despite them, Congress would do well to pass this bill. It's half a loaf, or perhaps less than half. But it will get the compensation process started. The present nonsystem is an offense to conscience. This country, drawing enormous benefits from vaccination, has not acknowledged its debt to those unfortunate children whom the vaccine injures