US Measles Outbreak 2026: Cases Surpass 2,300, Highest Since 1991

The United States has recorded more than 2,300 confirmed us measles cases in 2026, marking the country’s highest annual tally in 33 years and surpassing the total number of infections reported in 2025. According to the latest public health data, the outbreak has reached levels not seen since 1991, with 43 states and Washington, D.C. reporting at least one confirmed case — highlighting a significant resurgence of one of the world’s most contagious vaccine-preventable diseases.

What’s Driving the Surge in Measles Cases

Health authorities attribute the sharp rise in cases to:

• Declining childhood vaccination coverage
• Increased transmission within under-immunised communities
• Multiple simultaneous outbreaks across the country

The surge comes amid major changes in the US public health landscape following the appointment of Robert F. Kennedy Jr. as the country’s Health Secretary. Reports indicate that several Centers for Disease Control and Prevention (CDC) scientists were dismissed, while portions of federal funding for local public health programmes were frozen — prompting concerns among healthcare experts about the nation’s outbreak preparedness and immunisation infrastructure.

How Contagious Is Measles?

According to the US Centers for Disease Control and Prevention (CDC), measles is among the most infectious viral diseases, with up to 90% of susceptible individuals exposed to an infected person likely to contract the virus. The disease can lead to serious complications including:

• Pneumonia
• Encephalitis
• Death — particularly among young children, pregnant women and immunocompromised individuals

The World Health Organization (WHO) estimates that maintaining at least 95% coverage with two doses of the measles-containing vaccine is essential to achieve community immunity and prevent sustained transmission.

A Global Pattern: Declining Vaccination Rates Worldwide

The resurgence reflects a broader global trend. WHO and UNICEF have repeatedly warned that disruptions to routine immunisation services and increasing vaccine hesitancy have left millions of children vulnerable to vaccine-preventable diseases. In 2024, global estimates indicated that over 22 million children missed their first dose of the measles vaccine, increasing the risk of outbreaks across multiple regions.

Public health experts caution that declining vaccination rates could reverse decades of progress made in measles elimination efforts.

Why Vaccination Remains the Best Protection

The record number of measles infections in the United States underscores the critical importance of sustained immunisation programmes, disease surveillance, and rapid outbreak response. Health experts continue to recommend timely administration of the Measles, Mumps and Rubella (MMR) vaccine, which provides approximately 97% protection after two doses.

As cases continue to rise, federal and state health agencies are expected to intensify vaccination campaigns and strengthen surveillance measures to contain further transmission and protect vulnerable populations.