Why didn’t the United States have enough vaccine to fight swine flu this fall? It’s partly because federal health officials didn’t mix adjuvants into the drug. Adjuvants are substances that boost the immune system’s response to a vaccine, so that less vaccine is needed per dose. Using them could have allowed us to create up to four times more H1N1 vaccine doses than we have. Most of Europe used adjuvants; so did Canada. Why didn’t the feds?

They were too worried about spooking anti-vaccine activists, many of whom claim adjuvants contribute to autism. This almost certainly isn’t true: Adjuvants have been widely used for years, with no reputable study suggesting a link between them and autism. But federal officials feared people would avoid the H1N1 vaccine if it included adjuvants. As Anne Schuchat of the Centers for Disease Control and Prevention said in congressional testimony last month, “The public’s confidence in our vaccine system and in vaccines in this country [is] very, very fragile.”

Clive Thompson with his nomination for worst idea of the decade.