More kindergarten students (4.2%) were exempted from at least one vaccination during the 2025-26 school year than in the previous year (3.6%), the Centers for Disease Control and Prevention (CDC) said yesterday. 

The increase in vaccine exemptions could mean more infectious disease outbreaks. 

“We should be worried, because we’re already seeing the consequences of declines in vaccination. All you have to do is look at measles,” Jeanne Marrazzo, MD, MPH, CEO of the Infectious Diseases Society of America (IDSA), told CIDRAP News. “The less we see people taking up vaccinations, the more we’re going to see these cases accumulate.” 

Lower uptake than needed for herd immunity

During the 2025-26 school year, an estimated 280,000 children started kindergarten without proof that they completed the measles, mumps, and rubella (MMR) vaccine series. In total, 92.4% of kindergarteners received it—below the proportion needed to prevent measles from spreading in the community. 

“More than a quarter of a million children started kindergarten last year without protection from the MMR vaccine,” Andrew D. Racine, MD, PhD, president of the American Academy of Pediatrics (AAP), said yesterday in a statement. “For some diseases like measles, even a small decrease in vaccination rates can lead to more outbreaks of disease because community immunity requires over 95% of susceptible individuals to be immunized.”

A similar percentage of kindergarteners as that receiving the MMR vaccine received the diphtheria, tetanus, and acellular pertussis (DTaP) vaccine (92%). “When it comes to vaccination rates, however, anything less than achieving an A+ grade is not good enough,” Racine said.