11 August 2026
An executive order signed by U.S. President Donald Trump instructs health authorities to modify childhood immunization guidelines by separating the combined measles, mumps, and rubella (MMR) vaccine into three separate injections administered during distinct medical visits. The directive has drawn sharp criticism from medical associations, public health experts, and lawmakers, who argue that it directly contradicts established medical and scientific consensus. Is this true?
There are currently no single-antigen vaccines licensed, manufactured, or available in the United States for measles, mumps, or rubella individually. The only formulations approved by the FDA and currently available in the U.S. market are combination vaccines: M-M-R II (Merck & Co.), PRIORIX (GlaxoSmithKline), and the quadrivalent MMRV vaccine (ProQuad), which also includes varicella. According to the CDC, combination vaccines are important for maintaining high immunization coverage.
