U.S. measles cases hit 1,514 on fresh outbreaks in Utah, Arizona
Measles infections in the U.S. have reached 1,514 this year, as outbreaks continue to spread and routine childhood vaccinations fall.
The U.S. Centers for Disease Control and Prevention on Wednesday reported infections in 41 states. Cases are now being driven by travel and fresh outbreaks in Utah and Arizona after Texas declared its outbreak had ended in August.
The Utah Health Department confirmed 41 cases as of Sept. 23, mostly related to exposures at a high-school and a local Chick-fil-A chain restaurant. Arizona has recorded 46 cases along the Utah border, the health department said.
The surge in measles cases this year, which has reached levels not seen since 1992, have alarmed public health experts. There have been 40 outbreaks this year, compared with 16 for all of 2024.
Childhood vaccination rates have declined in the U.S. The CDC reported only 92.5% of kindergartners in 2024 were vaccinated against measles, mumps and rubella, down from 92.7% the year prior. Less than 90% of kindergartners in Utah and Arizona are vaccinated with the MMR shot – below the 95% level required for herd immunity to stop the spread of the highly contagious disease. The MMR vaccine is 97% effective in protecting against the virus after two doses.
This year’s case count was first driven by an outbreak in Texas among the unvaccinated Mennonite community. Three people have died from a measles infection since the Texas outbreak began in January.
On Sept. 18, an influential vaccine panel – hand-picked by Health Secretary Robert F. Kennedy Jr. – voted to tweak the childhood vaccine schedule. The Advisory Committee on Immunization Practices said children under 4 should not be given a combination shot for measles, mumps, rubella and varicella, the virus that causes chickenpox, because it increases the rare risk of seizures. Only 15% of children get the combination shot for their first dose. People can still get this MMRV shot for the second dose.
The shot’s manufacturer Merck & Co., has said “undermining MMRV vaccine access and confidence poses a significant health risk.”