The acting director of the Centers for Disease Control and Prevention (CDC) on Monday endorsed President Trump’s call to split up the measles, mumps and rubella (MMR) vaccine despite there being no research to support such a massive change.
“I call on vaccine manufacturers to develop safe monovalent vaccines to replace the combined MMR and ‘break up the MMR shot into three totally separate shots,’” Jim O’Neill posted on social platform X, linking to an earlier post from Trump where he told pregnant women not to take Tylenol, called for breaking up the MMR shot and said the hepatitis B vaccine should be delayed until kids are at least 12 years old.
O’Neill gave no reason why he thinks separating the shots and spreading them out over time would be beneficial, but his comments build on the administration’s public skepticism of vaccines.
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O’Neill’s post came the same day the CDC accepted a recommendation from its vaccine advisory panel that toddlers receive the chickenpox vaccine separate from the measles, mumps and rubella shot, rather than as a combined vaccination.
The combination MMR vaccine was licensed in 1971, and monovalent shots were phased out in 2009 due to the success of the combination shot.
According to the American Academy of Pediatrics, separating the components would mean unnecessary delays, leaving children susceptible for a longer period of time to serious, life-threatening diseases.
Health experts say the idea of bringing them back doesn’t make sense, especially at a time when vaccine skepticism is rising.
The current recommendation is that a child should get two doses of MMR; the first between 12 and 15 months, and the second between the ages of 4 and 6 years. If they were split apart, a child would need to get six separate shots.
“I think that that would not be met with any enthusiasm by, or acceptance by, either providers or parents who would see their children inoculated with substantially more doses of vaccine,” said William Schaffner, an epidemiologist and professor of public policy at Vanderbilt University.
It would also mean an increase in costs, because each visit and the administration of the vaccine comes with a separate charge.
“So it would increase the cost of the vaccination program to no benefit. As a matter of fact, we can predict just [as] the sunrises in the east and sets in the west, that there would be more missed vaccine appointments,” Schaffner said. “I cannot think of a single benefit of splitting up these vaccines. It was a terrific scientific triumph to be able to put them all together.”
It would also be a massive logistical lift for drug companies to develop the shots, which don’t exist in the U.S.
Vaccines would have to undergo a lengthy review process, as they’d be considered new products. Companies would need to reorient their product pipelines, conduct clinical trials, and then apply for Food and Drug Administration licensure, which would take years.
Splitting up the shots would also upend pediatric practices and put a financial burden on providers. Instead of stocking one vaccine, pediatricians would have to stock three different ones and then track the separate shots for each of their patients.