U.S. kindergarten vaccine exemptions hit record high amid rising measles cases

A surge in non-medical vaccine exemptions among U.S. kindergartners reaches new peak, raising concerns over declining herd immunity as measles cases escalate and policy debates intensify.

The share of U.S. kindergartners with a vaccine exemption reached a new high in the 2025-26 school year, according to federal data that come amid a sharp rise in measles cases and renewed debate over childhood immunisation policy. The CDC said exemptions climbed to 4.2%, up from 3.6% a year earlier, meaning roughly 155,000 children began school without at least one required shot.

Most of the increase came from non-medical exemptions, which are typically based on religious or personal-belief claims and are regulated by states rather than Washington. The CDC said 24 states now report exemption rates above 5%, a level that public health experts say can leave communities vulnerable when disease spreads.

Coverage also slipped for the vaccines the agency tracks most closely, including measles, mumps and rubella, diphtheria, tetanus and acellular pertussis, polio and chickenpox. CDC school vaccination data show declines in more than half of states for the second year in a row, while the agency’s measles figures show 2,170 confirmed cases as of July 2 across 41 jurisdictions, with 93% linked to outbreaks.

Andrew Racine, president of the American Academy of Pediatrics, warned that even modest drops in vaccination can undermine herd immunity against measles, which requires more than 95% protection among those susceptible. He said the risk is real, noting that more than a quarter-million children started kindergarten last year without protection against measles, mumps and rubella. The figures land as the White House presses federal health officials to reconsider the childhood schedule, including splitting the combined MMR vaccine into separate shots, even though the CDC says there is no published evidence that this would help.