The contentious executive order by President Donald Trump that immunisations for measles, mumps and rubella should be given in individual jabs in three different appointments instead of the standard combination shot has been met with resistance by scathing experts, reports The New York Times.
Trump has claimed that “together, there could be a possibility they’re quite lethal”, but the combination MMR shot has never been linked to a risk of death, and there is no evidence that splitting it into its three components is any safer or more effective.
The combo shots have been used in the United States since 1971, and were introduced only after careful comparison against individual shots. They have been given to hundreds of millions of children.
Complicating the issue, separate vaccines for measles, mumps or rubella have not been available in the country for many years, and vaccine manufacturers said it would take a minimum of five to 10 years for them to be tested and made available.
“We don’t have any way to implement what he’s suggesting,” said Dr Kathryn Edwards, a retired vaccinologist and professor emerita at Vanderbilt University who studied individual and combination vaccines.
“It’s just simply more confusion for the poor parents,” she added. “And it’s just showing the world that our health system and our Department of Health and Human Services and our President are totally uninformed.”
Trump’s executive order carries no legal weight and does not affect the availability of the current combination vaccines.
States set requirements for which vaccinations children should get, and mandates across Republican and Democratic states have been remarkably similar over decades.
Combination shots were developed in part to address parents’ worries that their children were becoming “pin cushions” for vaccines, said Dr Frank DeStefano, who led the vaccine safety office at the Centres for Disease Control and Prevention from 2009 to 2021. No safety concerns emerged in the years of clinical trials that compared the two approaches.
“It’s never been demonstrated that separating the vaccines is any safer than combined vaccines,” he said.
Trump said his executive order was based primarily on (unsubstantiated) theories that childhood vaccines can cause autism. Those concerns have been thoroughly researched and debunked since a 1998 study – which was later retracted and exposed as fraud – floated the idea that the measles vaccine caused autism.
“These ideas never die,” DeStefano said. “They’re zombie ideas. They keep popping up.”
Requiring parents to take their children for shots on three separate visits may deter some from getting these, and decrease immunisation rates, or at least delay protection for vulnerable young children.
In studies that compared timing of shots, parents who had to take their children in more often ended up dropping out because of the inconvenience, Edwards said.
Japan offers a cautionary tale for countries that rescind combination shots. In 1993, the country paused use of an MMR vaccine containing the Urabe mumps virus – which is different from the one used in the United States and Europe – because it caused aseptic meningitis in 0.05% of the recipients.
That type of meningitis resolves on its own and does not cause long-term damage. Still, responding to parents’ concerns, Japan switched to recommending individual shots for measles and rubella, and made the stand-alone mumps shot voluntary.
Use of the mumps shot “dropped to almost nothing, very quickly”, said Dr Margie Andreae, a paediatrician at the University of Michigan who studied the events.
Cases of mumps soared, and caused aseptic meningitis in 1.24% of the children, as well as more harmful types of meningitis, brain damage and hearing loss.
And vaccination for measles and rubella also plummeted, leading to surges in those illnesses.
“There’s strong evidence that splitting multicomponent vaccines into single components leads to decrease in immunisation coverage rates,” Andreae said.
If immunisation rates for measles in the US drop to a similar level, according to one modelling study, the country may see 11.1m cases of measles over 25 years. This year, a much smaller drop in the vaccination rate has already led to the highest number of measles cases observed in more than 25 years.
The MMR vaccine relies on weakened live viruses, which change over time, so companies cannot simply resurrect the individual shots, which were phased out in 2009.
“Essentially, these would be considered three investigational vaccines and would require full clinical trial testing and regulatory review for each new product to be licensed,” said Dr Paula Annunziato, who heads vaccine clinical research at Merck, which manufactures one of the two MMR shots available in the United States.
Alison Hunt, a spokeswoman for GSK, which makes the other one, said: “We stand by the safety and effectiveness of our combination vaccines, which are backed by decades of global use and robust scientific evidence.”
See more from MedicalBrief archives:
Trump orders MMR vaccine to be split into three jabs
US experts dispute calls for MMR jab to be split into three
Kennedy enrages supporters by now endorsing MMR vaccine
Measles jab a personal choice, says Kennedy after child’s death