280,000 US Kindergarteners Lack MMR Vaccine as Measles Surges to Worst Year Since 1991

At least 280,000 US kindergarteners did not receive the MMR vaccine, Dr. Paul Offit of Children's Hospital of Philadelphia told The Guardian. National MMR coverage fell to 92.4%, below the 95% threshold needed for herd immunity against measles — a virus so contagious that one infected person can infect 12 to 18 susceptible people. The data arrives amid the worst US measles year since 1991, with outbreaks in Utah and South Carolina.