In 2023, a federal judge ordered a sweeping rollback of Mississippi's strict school vaccination requirements, a ruling that concerned some medical professionals in the state. The decision affected Mississippi's historically high childhood vaccination rates, which had been among the highest in the United States despite the state ranking low on other health measures.

Following the court-ordered changes to the vaccine rules, Mississippi experienced a surge in whooping cough cases, including the death of an infant. The timing of the outbreak coincided with the loosened vaccination requirements, though health officials have not established a direct causal link.

The campaign to modify Mississippi's vaccination rules had been developing over several years. Two individuals with connections to Robert F. Kennedy Jr., who has been nominated as U.S. health secretary, were involved in orchestrating efforts to change the state's vaccine policies.

Mississippi had previously maintained some of the nation's most stringent school vaccination requirements, contributing to high immunization rates among children. The state's approach to childhood vaccinations had been viewed as a public health success story, particularly given its challenges in other health metrics.

The recent developments have drawn attention to the ongoing national debate over vaccination policies and their implementation at the state level. Kennedy, known for his vaccine-skeptical positions, has reportedly reduced his public discussions about vaccines, according to reporting that cited internal campaign communications.