President Donald Trump signed an executive order on Monday recommending that the measles, mumps, and rubella (MMR) vaccine be separated into three individual injections. The directive requires federal health officials to produce a plan for this transition within 90 days. The administration stated that the order is intended to provide parents with more options through a market-based solution, though officials noted they have not yet established specific incentives for manufacturers to implement the change.
The MMR vaccine has been administered as a single, combined shot in the U.S. since 1971. Major vaccine manufacturers Merck and GSK indicated they have no current plans to produce monovalent—or single-antigen—vaccines for these diseases. Both companies and several scientific groups noted that no new scientific data was provided by the administration to support the clinical benefit of splitting the doses.
Industry representatives and medical experts stated that splitting the vaccine would increase the number of required clinic visits from two to six. Dr. Ronald G. Nahass, president of the Infectious Diseases Society of America, said that complicating the vaccination process could lower compliance rates at a time when U.S. measles cases have reached their highest level in 30 years. Conversely, President Trump stated last week that "nothing bad can happen" from breaking up the shots.
For the pharmaceutical industry, the scale of the change involves significant time and financial investment. A source familiar with manufacturing reported that bringing three separate vaccines to market would take years and potentially cost billions of dollars in research and new manufacturing lines. Currently, no single-antigen vaccines for these three diseases are approved by the Food and Drug Administration (FDA). The federal Vaccines for Children program currently purchases approximately 50% of all childhood vaccines at a discount, and the International Monetary Fund has previously noted that vaccine development carries a high risk of being unprofitable.
The knock-on effects could include a shift in how the FDA handles vaccine approvals and a potential decrease in national immunization rates if patients fail to complete the six-dose series. While the administration suggested market demand will drive company decisions, manufacturers stated that combination vaccines are currently more effective at ensuring children receive all recommended doses on time. The next step in this process is the delivery of a 90-day plan by a Department of Health and Human Services (HHS) task force, which will detail how the administration intends to work with companies to provide these options.