“This is based on what I feel.” That was the president last September, explaining why he wanted the measles, mumps and rubella (MMR) vaccine broken into three separate shots. On Monday, he signed an executive order instructing exactly that.

Four decades in intensive care have taught me what a feeling costs once it becomes national policy. Children will be hospitalized who did not need to be. Some of them will die. No one can name those the vaccine has saved, because prevented harm is invisible by definition, and that invisibility is what makes preventive medicine easy to dismantle and hard to defend.

The order rests on a single complaint, stated in the White House’s own fact sheet: American children are recommended more vaccine doses than children anywhere in the developed world, 84 doses across 57 injections by 2024 against 23 doses in seven injections in 1980. Section 2 of Monday’s executive order directs that the MMR be given as three single-disease shots, and that “to the maximum extent feasible, all childhood immunizations should be administered at separate medical visits”. Not only the MMR: every childhood immunization.

No evidence supports the spacing. The most thorough review of the American schedule ever conducted, by the Institute of Medicine in 2013, found no safety signal and no case for spreading doses out; a delayed-schedule trial, if held, could not ethically be run, because delay only lengthens the time a child is unprotected.

The president and Robert F Kennedy Jr, his health secretary, returned repeatedly to autism as the order........

© The Guardian