With no new data or clear reasoning, a panel of advisors hand-selected by anti-vaccine Health Secretary Robert F. Kennedy Jr. voted last September to strip federal recommendations for the MMRV combination shot against measles, mumps, rubella and chickenpox.

An analysis published today in JAMA Network Open does the work the advisors neglected to do before the vote and shows how harmful this decision is to vulnerable US toddlers. The study found that only about 15% of children received the MMRV vaccine between 2015 and 2025, a small percentage compared to those receiving separate vaccines.

The decision meant private health insurance providers would no longer be required to cover the vaccine, meaning it will now be less accessible for many American children, particularly from low-income families. The federal program that provides vaccines to about half of all US children was also affected by this change.

This analysis underscores the importance of robust scientific evaluation in public health decisions, especially when they impact vulnerable populations. It highlights a potential gap in how advisory committees approach decision-making frameworks for vaccine recommendations.