The United States is experiencing its worst measles outbreak in 35 years and a sustained pertussis surge, driven by declining vaccination rates and unprecedented federal actions to weaken childhood vaccine recommendations. Since January 20, 2025, more than 3,600 confirmed measles cases have been reported across 46 states, with 4 deaths and an 11% hospitalization rate. The Trump administration, under HHS Secretary Robert F. Kennedy Jr., gutted the childhood vaccine schedule from 18 to 11 recommended diseases, fired all expert ACIP members, terminated $500 million in vaccine research, and altered CDC messaging to suggest a link between vaccines and autism. A federal judge blocked these changes on March 16, 2026, ruling they likely violated federal law. Meanwhile, California has emerged as the strongest state-level counterweight, but San Joaquin County faces a “very high risk” rating for measles due to only 60% of children under 5 being vaccinated.