The United States has experienced a marked increase in measles cases in 2026, with the number of confirmed infections surpassing 2,300, the highest annual total since the disease was declared eliminated in 2000. Health officials reported this milestone on Friday, noting that the current case count exceeds last year’s record of just over 2,200 and represents a significant rise compared to previous decades. The surge highlights growing concerns about the potential for measles to become endemic in the country once again.

Outbreaks in several states have driven much of the increase. Utah and South Carolina accounted for roughly half of the total cases, with South Carolina’s health authorities imposing quarantine measures for unvaccinated students following exposure and eventually declaring the outbreak contained within seven months. In contrast, Utah’s outbreak has persisted for over a year, partly due to uneven quarantine enforcement. Other states, including Pennsylvania and Virginia, have also reported rising case numbers.

This resurgence is linked to declining vaccination rates, particularly for the measles, mumps, and rubella (MMR) vaccine. Nationwide, vaccination coverage among kindergartners dropped to 92.5% during the 2024-25 school year from 95.2% in 2019-20, falling below the 95% threshold typically required to maintain herd immunity. Pockets of lower vaccination rates have emerged in various communities, with some schools reporting coverage as low as 20%. For instance, in Idaho, only 78.5% of kindergartners were vaccinated before the 2024-25 school year, the lowest rate among all states. Experts warn these undervaccinated groups provide fertile ground for measles transmission.

Health experts emphasize that these outbreaks underline the risks posed by vaccine hesitancy and gaps in immunization efforts. Some public health officials have critiqued recent federal approaches, arguing that stronger, more unified messaging about vaccine safety and importance is needed. The current administration’s stance on vaccine policies, including the halting of vaccine hesitancy research funding and statements minimizing measles risks, has raised concerns among some specialists about its impact on immunization rates.

In November, a panel of international experts from the Pan American Health Organization will review whether the United States has lost its measles elimination status. The designation requires no continuous endemic measles transmission for at least 12 months. Losing this status would mark a significant public health setback, indicating that the virus is circulating regularly within the country rather than being imported and quickly contained.

While the overall vaccination rate remains relatively high and continues to prevent even larger outbreaks, the steady presence of measles cases points to the pressing need for renewed vaccination efforts and public health interventions to address declining immunity in vulnerable populations.