Reporting flu vaccine science

When reporting on medical studies, the popular press has a habit of sensationalising. So the muted response to a recent research paper reporting increased risk of miscarriage with influenza vaccines was at first sight surprising.

The study, funded by the Centers for Disease Control and Prevention, found that women who had received an influenza vaccine containing the 2009 pandemic strain pH1N1 and who were also vaccinated in the next flu season had a statistically significant, 7.7-fold higher odds of spontaneous abortion within 28 days of the second vaccination.1 (Absolute risk increase could not be calculated because it was a case-control study.) The concerning odds ratio fostered extensive discussion in the paper. But the news media projected an air of calm, highlighting the observational study’s many limitations.

The headline on the health news website STAT read: “Study shows miscarriage risk may have increased after flu shots, puzzling researchers”2—as if the increased risk was in doubt. A widely syndicated Associated Press story ran with the headline, “Study prompts call to examine flu vaccine and miscarriage,”3 discounting the fact that this had been the purpose of the reported study. The Washington Post initially declared: “Researchers find hint of a link between flu vaccine and miscarriage”—but within hours that headline was softened to, “What to know about a study of flu vaccine and miscarriage.”4

None …