According to the US Centers for Disease Control and Prevention, two doses of the MMR (measles, mumps and rubella) vaccine are 97% effective at preventing measles, while one dose is 93% effective. It is uncommon for someone who is fully vaccinated to develop measles, although the first breakthrough case of 2025 was recently detected in Colorado.

There are 1,288 confirmed measles cases across the U.S., the Centers for Disease Control and Prevention (CDC) said, warning that numbers are the highest they've been since 1992. Dr. Celine Gounder joins "CBS News 24/7" with more details.

Thirteen percent of the confirmed measles cases in the U.S. this year have resulted in hospitalization, according to the CDC, including 21% of cases in children five or younger. Three people are confirmed to have died. At the same time, experts stress that this issue goes beyond measles.

The U.S. has now recorded more confirmed measles cases this year than in any year in well over a quarter-century.

Measles cases in the US have reached a 33-year high, with nearly 1,300 cases reported in the last seven months, according to the latest data from the Centers for Disease Control and Prevention. At least 1,

Measles cases in the U.S. are at their highest in three decades The U.S. is having its worst year for measles spread in more than three decades, with a total of 1,288 cases nationally and another six months to go in 2025.

Kent County's latest measles case is part of a "troubling resurgence of vaccine-preventable diseases ... here and around the world.”

Kent County has confirmed its second measles case of the year in a young child. The child’s family had a recent history of international travel, the Kent County Health Department announced Wednesday,

The state of Utah is up to nine cases of measles, health officials say. Most are in one county, and all are people who were unvaccinated.