President Donald Trump signed an executive order this week recommending that the measles, mumps, and rubella (MMR) vaccine be administered as three separate shots instead of the current single combination vaccine. Trump stated, without providing evidence, that separating the immunizations would be safer.
However, the order has drawn criticism from doctors and public health organizations who point to decades of research confirming the safety and efficacy of the MMR vaccine as it is currently administered. They argue that splitting the vaccine into individual doses would impose significant logistical challenges for families and potentially decrease vaccination rates, especially as the U.S. is experiencing its highest number of measles cases in over 30 years.
The MMR vaccine, first combined in 1971, has been shown in studies to provide protection comparable to individual shots. Public health specialists expressed concern that more injections and appointments could lead to more children missing their required immunizations.
"If you separate the vaccine into its three component parts, you have to have six shots instead of two, which makes it more burdensome and difficult," Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, told ABC News. "No doubt [that] will mean that there will be children who fall through the cracks during what is the worst measles epidemic we've had in this country in more than 30 years."
Dr. Hana El Sahly, a professor at Baylor College of Medicine, highlighted that there are currently no single measles, mumps, or rubella vaccines licensed for use in the U.S., nor are any pharmaceutical companies reportedly planning to develop them. Such a development would require extensive and costly research, clinical trials, and regulatory approval.
El Sahly also noted the practical difficulties for healthcare providers. "A general pediatrics office is one of the busiest offices when it comes to healthcare delivery," she said. "So instead of administering a safe and effective vaccine to a child in two visits over four years, we are demanding -- or the directive points them to -- six visits over that span of time. That multiplies by three the number of visits required to fully immunize the child against MMR. Major, major obstacle to healthcare delivery and access to care."
This potential increase in required visits could strain appointment availability in busy pediatric offices and create additional barriers for parents seeking to ensure their children are fully vaccinated.
Concerns about vaccine safety have been amplified by unsubstantiated claims linking vaccines to autism. The MMR vaccine has been a focal point of this discussion due to a 1998 study that was later retracted and widely discredited, with its author losing his medical license. Numerous subsequent studies and meta-analyses have found no link between the MMR vaccine and autism.
Additionally, the notion that multiple vaccines can overwhelm a child's immune system has been refuted by experts. Dr. Offit explained that modern vaccines contain fewer active antigens than vaccines administered decades ago, and that children are constantly exposed to a far greater number of immunological challenges from their environment daily. "So, the notion that vaccines in any way weaken or overwhelm or perturb our immune system is just nonsensical," Offit stated.