The Centers for Disease Control and Prevention (CDC) counted 4,588 confirmed U.S. measles cases as of Oct. 22, more than twice 2025's total, while The Guardian reported some parents are choosing earlier second MMR doses.
The agency tallied 4,588 confirmed cases as of Oct. 22, compared with 2,289 for 2025. The CDC has cited weaker vaccination coverage, communities with lower rates and increased measles activity abroad as factors in the rise.
CDC guidance allows a second dose of the measles, mumps and rubella (MMR) vaccine once at least 28 days have passed since the first. The Guardian reported that Germany, the United Kingdom and France have guidance for an earlier second dose. Germany recommends the second MMR dose at 15 months, no sooner than four weeks after the first, according to the Robert Koch Institute.
The Guardian reported that the routine U.S. schedule sets the second dose at ages four to six. It said that window places vaccination before kindergarten and may mean fewer doctor visits.
