US measles cases surpass 5,000, highest since 1991

US measles cases have surpassed 5,000 in 2026, marking the highest annual total since 1991 across 45 states. Hardest hit is Pennsylvania with over 1,460 cases. The resurgence threatens the nation's 26-year elimination status, which the Pan American Health Organization will evaluate. Tensions persist over death counts as HHS Secretary Robert F. Kennedy Jr. altered tracking standards, conflicting with state health reports.

US nationwide measles cases and demographics

• ▪Nationwide hospitalizations linked to measles in 2026 stood at 562, representing 11% of all reported cases in the United States, according to the CDC
• ▪The CDC reported that 96% of all US measles infections in 2026 occurred among individuals who were unvaccinated or whose vaccination status was unknown
• ▪According to CDC data, adults aged 20 and older accounted for 2,132 US measles cases in 2026, while children aged 5-19 accounted for 2,104 cases and children under 5 accounted for 908 cases
• ▪The US Centers for Disease Control and Prevention confirmed 5,182 measles infections in the US on November 6, 2026, marking the highest annual total since 1991 across 45 states

Pennsylvania measles outbreak and response

• ▪Pennsylvania requested on-the-ground assistance from the CDC and received one specialist to assist state officials with data analysis and outbreak forecasting
• ▪Pennsylvania health officials ramped up vaccinations in September and October 2026, providing over 100,000 MMR doses, including to undervaccinated Amish and Mennonite populations experiencing high case rates
• ▪Pennsylvania has been the hardest-hit US state in the 2026 measles outbreak, recording 1,467 cases and 287 hospitalizations since April 2026

Measles cases in South Carolina and Utah

• ▪Utah's measles outbreak has been actively circulating since June 2025 and has infected more than 700 people total
• ▪CDC data updated as of November 5, 2026 listed South Carolina with 670 measles cases and Utah with 536 cases, representing the next-highest totals behind Pennsylvania

Measles deaths in New York and Wisconsin

• ▪New York Governor Kathy Hochul issued a state of emergency following the state's first measles-associated death in 30 years confirmed on November 2, 2026
• ▪Wisconsin reported the measles-associated death of an infant on November 5, 2026, marking the state's first measles mortality in decades

Federal tracking and disputes over measles deaths

• ▪Pennsylvania's health department confirmed six measles-associated deaths in 2026, sparking a political dispute between HHS Secretary Robert F. Kennedy Jr. and Governor Josh Shapiro after Kennedy questioned the deaths' validity
• ▪The CDC recognizes only four measles-associated deaths nationwide in 2026 because HHS Secretary Robert F. Kennedy Jr. switched the tracking standard from state health department figures to National Center for Health Statistics mortality data
• ▪The CDC is working with an outside group of epidemiologists to determine the definition of a measles fatality

RFK Jr.'s actions and views on MMR vaccines

• ▪Health and Human Services Secretary Robert F. Kennedy Jr. and President Donald Trump proposed an August 2026 executive order to split the MMR vaccine into three separate shots, which drugmakers Merck & Co. and GSK Plc noted would be time-consuming and costly
• ▪Health and Human Services Secretary Robert F. Kennedy Jr. has expressed doubt about the MMR shot and touted unproven remedies instead

Threats to US measles elimination status

• ▪The Pan American Health Organization will review transmission data to determine whether the US will lose its measles-eliminated country status held since 2000
• ▪Under Pan American Health Organization rules, the United States will lose its measles elimination label if a single viral strain is determined to have continuously circulated for 12 months