The Centers for Disease Control and Prevention (CDC) recently released an alarming update regarding measles cases across the United States. As of November 6, 2026, more than 5,000 confirmed cases have been documented this year, marking the highest number of cases in 34 years.
According to the CDC’s data, there have been a total of 5,182 confirmed measles cases from the beginning of the year to date. This figure represents a staggering increase when compared to last year’s total of 2,289 cases, making it the highest annual total since 1992.
Breaking this figure down further, 5,164 of the confirmed cases were reported from 47 states. Additionally, there were 18 cases identified among international visitors who entered the United States.
It is important to note, as clarified by the CDC, that this number reflects only the cases that have been officially reported by various states. State health departments may have more immediate and comprehensive information regarding the current state of the outbreak.
Currently, health departments in states such as Pennsylvania, Utah, Maryland, Wisconsin, and Delaware are actively providing real-time updates about measles outbreaks online.
The data underscore a concerning trend, with 43 new outbreaks reported this year, defined as three or more related cases. Among the total confirmed cases, a significant 96%—approximately 4,993 out of 5,182—are linked to these outbreaks. Of these, 3,608 cases originated from outbreaks that began this year, while 1,385 were tied to outbreaks that started in 2025.
In contrast, the entirety of 2025 saw 48 outbreaks, with 90% of the cases classified as linked (2,066 out of 2,289). In 2024, there were 16 outbreaks reported, with a lower proportion of linked cases at 69% (198 out of 285).
The CDC defines “outbreak” or “cluster” as a series of epidemiologically related cases occurring within a specific time and geographic range. This definition is critical for public health authorities in their response to these outbreaks.
The CDC emphasizes the importance of the measles, mumps, and rubella (MMR) vaccine, asserting that it is both highly safe and effective. When vaccination rates in a community exceed 95%, the majority of individuals can gain protection through herd immunity.
However, vaccination rates for children in U.S. kindergartens have notably declined, dropping from 95.2% during the 2019-2020 school year to 92.4% for the 2025-2026 school year. This drop translates to approximately 280,000 kindergarteners facing an increased risk of infection.
Moreover, the CDC indicates that there can be substantial differences in vaccination rates across different regions. Even in states with overall high vaccination rates, there may still be areas where unvaccinated populations are concentrated. If the measles virus were to enter a community with unvaccinated individuals, it could easily trigger a larger outbreak.
The United States officially declared the elimination of measles in the year 2000, meaning there was no longer sustained transmission of the disease within the country. Any new cases were only recorded among individuals who had contracted the disease while abroad. At that time, the CDC heralded this development as a monumental achievement in public health.
Additionally, the CDC is collaborating with the Council of State and Territorial Epidemiologists (CSTE) to establish a standardized definition of measles mortality. This move aims to unify the classification and reporting of measles-related deaths across different regions.
It is crucial to remain aware that the data for the years 2025 to 2026 are preliminary and may be subject to adjustments as more information becomes available.