Federal data show kindergarten vaccine exemption rates rose to a record 4.2% nationally in the 2025-2026 school year, up from 3.6% the prior year, with MMR coverage at 92.4%. Exemptions increased in 41 states and D.C., affecting an estimated 155,000 children, and mark the fourth consecutive annual high. The data coincide with federal efforts to revise childhood vaccine guidance under Health Secretary Robert F. Kennedy Jr.