Public health officials have issued warnings that the return of students to school for the 2026-27 academic year may accelerate the spread of measles. The United States is currently experiencing its highest number of measles cases in 35 years, with nearly 3,000 cases recorded across 47 jurisdictions and 36 new outbreaks identified so far this year.
The increase in cases follows a steady decline in childhood vaccination rates. According to the Centers for Disease Control and Prevention (CDC), the vaccination rate for measles, mumps, and rubella (MMR) among kindergarteners fell to 92.4 percent during the 2025-26 school year. This remains below the 95 percent threshold that public health experts state is necessary to prevent widespread community transmission.
Lori Freeman, CEO of the National Association of County and City Health Officials (NACCHO), stated that the current situation is likely to continue unless concerns regarding immunization are addressed. Meanwhile, Randi Weingarten, president of the American Federation of Teachers, attributed the surge to the administration’s handling of vaccine policy and funding for the CDC. Earlier this month, President Trump signed an executive order directing the MMR vaccine to be split into three separate shots, though several states including California and New York have maintained existing vaccine guidance.
Families will notice the impact through school health policies and potential exposure risks. Because measles is highly virulent—capable of infecting 90 percent of unvaccinated individuals exposed to it—a single case can lead to rapid transmission within a classroom setting. School nurses and administrators are being advised by NACCHO to update emergency operations plans for potential classroom transmissions as the new school year begins in late August. Parents in states like Virginia and Pennsylvania will see continued use of the combined MMR shot, as domestic manufacturers currently do not produce the individual monovalent vaccines required to fulfill the recent executive order.
The ongoing decrease in immunization rates sets a precedent for how infectious diseases are managed in public institutions. NACCHO is shifting its strategy toward community listening sessions and educational outreach rather than mandatory measures to address vaccine hesitancy. The primary upcoming milestones include the full reopening of U.S. public schools by the end of August 2026, which health officials will monitor to determine if the 36 existing outbreaks expand or if new clusters emerge in geographically concentrated social or religious networks.