In brief
The CDC announced that 5,182 measles cases have been confirmed in the United States so far this year, the highest number in 35 years. Children and teenagers make up about 60% of cases, and the outbreak is linked to declining vaccination rates among kindergarteners. The data spark a dispute over the national death toll, with Pennsylvania reporting more deaths than the federal agency lists.
On March 18, 2026 the Centers for Disease Control and Prevention (CDC) announced that 5,182 measles cases had been confirmed in the United States, the most in 35 years, according to Al Jazeera and Bloomberg.
The figure for the highly contagious but vaccine‑preventable disease is the highest number reported by the CDC since 1991 and is more than double the 2,289 cases confirmed in 2025.
Almost 60 percent of the confirmed cases are among children and teenagers, 18 percent of whom are under five and 41 percent between five and 19 years old, according to the same report.
The outbreak follows a decline in vaccination coverage among U.S. kindergarteners, which slipped from 95.2 percent during the 2019‑2020 school year to 92.4 percent in the 2025‑2026 school year.
According to CDC data four people have died of measles in 2026, but the national death toll is lower than the number of measles‑related deaths reported by state officials. Pennsylvania reports six deaths and 1,487 cases, the state's highest tally in a single year.
The discrepancy over deaths stems from Pennsylvania’s definition of measles‑associated deaths, which the state counts if a person with confirmed measles dies within 30 days of the onset of symptoms.
The CDC had initially included the deaths in its national count, but later removed them after the U.S. Health Secretary Robert F. Kennedy Jr. questioned the classification, sparking a dispute with Pennsylvania Governor Josh Shapiro.
