The grim news from the New York Times yesterday is that the swine flu vaccine is likely to cause an outbreak of misperceptions about its consequences for people’s health:

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…

Officials are particularly worried about spontaneous miscarriages, because they are urging pregnant women to be among the first to be vaccinated. Pregnant women are usually advised to get flu shots, because they and their fetuses are at high risk of flu complications, but this year the pressure is greater…

“There are about 2,400 miscarriages a day in the U.S.,” said Dr. Jay C. Butler, chief of the swine flu vaccine task force at the federal Centers for Disease Control and Prevention. “You’ll see things that would have happened anyway. But the vaccine doesn’t cause miscarriages. It also doesn’t cause auto accidents, but they happen.”

Unfortunately, human beings are terrible at counterfactual thinking — in this case, assessing what would have happened without the shot. That hasn’t changed since 1976, but the problem is likely to be much worse this time around for several reasons:

-The scale of the problem is much worse (the swine flu is already a global pandemic).
-Many people have been influenced by the false claim that childhood vaccines are responsible for the increase in autism diagnoses (among other things).
-Every crazy story blaming the vaccine for heart attacks, miscarriages, etc. will be spread around the world via cable news and the Internet within hours.

But what I’m really worried about is the possibility that an anti-vaccine backlash will become an ideological issue. Glenn Beck asked his audience Monday night “Am I going to allow the government to give my child a flu shot? … I have already made my decision, but everyone has to make their own decision … Who will allow their children to be given a flu shot by this government?” Given the frenzied opposition to President Obama on the right, it’s likely that the vaccination campaign will be portrayed as some sort of socialist plot.