As soon as swine flu vaccinations start next month, some people getting them will drop dead of heart attacks or strokes, some children will have seizures and some pregnant women will miscarry.

But those events will not necessarily have anything to do with the vaccine. That poses a public relations challenge for federal officials, who remember how sensational reports of deaths and illnesses derailed the large-scale flu vaccine drive of 1976.

This time they are making plans to respond rapidly to such events and to try to reassure a nervous public  and headline-hunting journalists  that the vaccine is not responsible.

Every year, there are 1.1 million heart attacks in the United States, 795,000 strokes and 876,000 miscarriages, and 200,000 Americans have their first seizure. Inevitably, officials say, some of these will happen within hours or days of a flu shot.