The news: Acting director of the CDC, Jim O’Neill, wrote in a post on X that pharma manufacturers should make separate shots for measles, mumps, and rubella (MMR) in place of the current vaccine, which combines the three.

O’Neill’s statement echoes recent comments from President Donald Trump, who said the MMR shot should be broken up into three. Trump provided no scientific evidence for this sentiment other than it’s based on what he feels.

Why it matters: Medical experts warn that splitting it into three would require more doctor visits and increase the risk of missed doses. For context, there aren’t any recommended or available separate single-disease vaccines for measles, mumps, and rubella in the US.

Since Trump’s comments, misleading information about the MMR vaccine has regained steam on social media. The idea of separating the MMR vaccine first gained traction in 1998 following a research paper from Andrew Wakefield, who linked the combined shot to increased risk of autism. That study has been retracted and debunked. However, recent social posts from Trump and one that went viral from Wakefield himself (whose medical license has been revoked in the UK) have reignited misinformation.

More people are subscribing to the incorrect theory that vaccines are safer when they’re spread out.

• 41% of parents say they agree with the view that children are healthier when their vaccines are spaced out and they don’t get multiple shots in one visit, per a survey last month from KFF and The Washington Post.
• About half of Republican parents hold this opinion, compared with 28% of Democrats.

Our take: Vaccine makers and pharma marketers must address criticism that the combined MMR shot is unsafe for children. Although people don’t have the option to break out the MMR vaccine into three doses, the administration’s rhetoric could drive more parents to skip or delay a needed treatment for their kids.

Messaging should emphasize how contagious measles is and the risks of lower vaccination rates when three appointments are required. Marketers will want to stress that breaking MMR into three vaccines offers no proven health benefit and undermines decades of successful disease prevention. The response should be framed around children’s health, safety, and scientific evidence—not politics. This means avoiding direct responses to social media posts from Trump and O’Neill, instead disseminating information through local pediatric clinics, pharmacies, and medical associations.