ONE THING to say about the coming shortage of flu vaccine is that we've been here before. Last fall, flu struck early, killing several children in November. The subsequent surge in demand led to local and national shortages in December. This year, the causes of the shortage are different: British officials have declared that some 48 million flu vaccine doses that Chiron Corp. produced in Britain, destined for the United States, are contaminated and cannot be sold. Food and Drug Administration officials are negotiating with their British counterparts, trying to determine whether the entire Chiron batch must be destroyed. But even if some vaccines are saved, the incident illustrates, in a novel way, the extraordinary fragility of the flu vaccine production system, which relies on a tiny number of suppliers and outdated technology to fulfill an unpredictable demand.

Officials at the Centers for Disease Control and Prevention say they will carefully track the distribution of the remaining 55.4 million doses to ensure that as many as possible are given to the 100 million to 150 million people at highest risk from flu: children ages 6 to 23 months, adults 65 and older, and the chronically ill. Officials from the Department of Health and Human Services have also taken some steps that will eventually produce emergency supplies. They are offering contracts to companies interested in creating a reliable vaccine "surge capacity," so that extra doses can be manufactured quickly in case of a flu pandemic, using both the traditional production methods, which rely upon chicken eggs, and newer methods based on cell cultures.

Ultimately, though, the reliable production of flu vaccines, indeed all vaccines, is going to require a more thorough renegotiation of the relationships between the government and the drug industry, which shies away from vaccine production because of the production risks -- note Chiron's troubles -- the unreliability of demand and the relatively slim profits. To ensure a dependable supply, at least some official bodies must guarantee the purchase of a certain number of doses at a set price, much in the way that Congress guaranteed, in its recent Project Bioshield legislation, that the government will purchase antidotes for potential bioterrorism epidemics.

In the short term, this year's flu season is going to require an unusual degree of national civic-mindedness. Healthy people should not get flu shots; they should be discouraged from doing so by those who dispense the shots, whether in doctor's offices, workplaces or shopping malls. Don't go to work when you're sick, don't send a sick child to school and cover your mouth when you cough. Sadly, that's the best advice we can offer.