Measles cases across the United States have reached their highest level in more than three decades, with several states reporting outbreaks and health officials raising concerns over declining vaccination rates.
In Maryland, health authorities confirmed 14 new measles cases this week, bringing the state’s total to 31 cases so far this year.
Of those cases, 27 involved people who were unvaccinated, with most of the infections recorded within the past six weeks. Cases have been reported in St. Mary’s, Carroll, Cecil and Charles counties, with St. Mary’s County recording the highest number at 13.
The Maryland Department of Health has urged residents to check their vaccination status, warning that measles spreads easily but that vaccinated people face minimal risk of infection.
Iowa is also experiencing an outbreak, with 17 confirmed cases linked to exposures at nine locations across the state. The locations include grocery stores, pharmacies and restaurants in Clive, West Des Moines, Des Moines, Ottumwa and Bloomfield. Thousands of people may have been exposed at the affected sites.
Pennsylvania has reported an even more serious development, recording two measles-related deaths this week. Both victims were unvaccinated residents of Lancaster County.
The deaths are reportedly the state’s first from measles in 35 years. Pennsylvania has recorded 393 measles cases across 28 counties so far this year.
Nationwide, the US Centers for Disease Control and Prevention (CDC) had confirmed 2,777 measles cases as of August 20, the highest annual total since 1991. The country recorded 2,289 cases and three deaths in 2025.
Health officials say the overwhelming majority of people infected with measles are unvaccinated.
Two doses of the measles, mumps and rubella (MMR) vaccine provide about 97% protection against measles. Among people who have not been vaccinated and are exposed to the virus, approximately nine in 10 are expected to become infected.
Measles typically begins with symptoms such as fever and cough, followed by a characteristic rash that spreads across the body. While some infections may be mild, measles can cause serious complications, including pneumonia, brain inflammation and severe immune-system complications, particularly in children.
The virus spreads through the air and is highly contagious, especially in crowded or enclosed settings such as airports and aeroplanes.
Nationally, about 92.4% of kindergarten children are fully vaccinated against measles, below the estimated 95% coverage needed to maintain strong community protection.
Meanwhile, vaccine exemptions have increased to 4.2%, compared with 1.6% a decade ago.
Health authorities continue to emphasise that the MMR vaccine is safe and remains the most effective protection against measles.