US Childhood Vaccination Rates Drop Amid Rising Measles, Whooping Cough Cases
Childhood vaccination rates in the US declined for all key vaccines in the 2025-26 school year.
Why it matters: Lower vaccination rates increase outbreaks of diseases like measles, affecting public health mandates and school policies. Legal professionals must track compliance risks and evolving exemptions.
- Vaccination coverage fell below 95% herd immunity threshold—92.4% for MMR and polio, 92% for DTaP nationally.
- Vaccine exemptions rose in 41 states and DC, reaching 4.2% nationally; Tennessee saw exemptions increase to 4.8%.
- Confirmed measles cases reached 1,983 in 2026, with 30 outbreaks; Oregon reported 45 cases so far, surpassing previous peaks.
- Colorado’s MMR coverage dropped to 87.7%, with exemptions rising to 4.7% affecting 2,800 children.
New data from the CDC report reveals significant declines in childhood vaccination rates for the 2025-26 school year across key vaccines including MMR (measles, mumps, rubella), DTaP (diphtheria, tetanus, and acellular pertussis), polio, and varicella.
Vaccination coverage nationally dropped below the 95% threshold necessary to maintain measles herd immunity, with MMR and polio at 92.4% and DTaP at 92%. Correspondingly, vaccine exemption rates increased to 4.2% nationwide, with 41 states and DC reporting rises. Tennessee exemplified this trend, where exemptions grew to 4.8%—up from 3.8% the prior year—amid increasing vaccine skepticism, according to state CDC data.
Heightened disease outbreaks have coincided with these declines. As of mid-August 2026, the U.S. had 1,983 confirmed measles cases, marked by 30 separate outbreaks. Oregon alone reported 45 measles cases—surpassing the 2024 peak of 27 cases (Oregon CDC report). Colorado experienced a similar drop in MMR vaccination coverage to 87.7%, linked to a 4.7% exemption rate impacting roughly 2,800 children (Colorado CDC data).
The resurgence of diseases like measles and whooping cough—the latter causing 500 cases and one death in Arkansas in 2025—reflects interrupted healthcare routines and heightened vaccine misinformation. Experts stress that "even small declines in vaccination rates can significantly reduce herd immunity," emphasizing vaccination as a crucial public health tool (CDC measles data).
For legal professionals in health sectors, these trends pose challenges regarding compliance with vaccination mandates, public health laws, and school entry requirements amid shifting exemption landscapes and ongoing outbreaks.
By the numbers:
- 92.4% — National MMR and polio vaccine coverage for kindergartners in 2025-26
- 4.8% — Vaccine exemption rate in Tennessee for 2025-26, up from 3.8% previous year
- 1,983 — Confirmed measles cases in the U.S. as of May 2026
Yes, but: While vaccination rates have declined nationally, some states like West Virginia maintain MMR coverage as high as 98.9%, indicating regional variation in compliance.
What's next: Public health and legal authorities will closely monitor the 2026-27 school year vaccination rates and outbreak numbers for policy adjustments and enforcement responses.