The Allegheny County Health Department is monitoring the spread of measles across Pennsylvania following an outbreak in Lancaster County. There are currently no confirmed cases of the virus in Allegheny County.
Five unvaccinated individuals in Lancaster County tested positive for the virus on Feb. 3. This local activity occurs amid a national surge in measles cases, with 662 infections reported across the United States in January 2026.
The Centers for Disease Control and Prevention reports that 97% of measles cases in the country involve people who are not vaccinated or have an unknown vaccination status. Health officials state that the measles, mumps and rubella vaccine is the most effective prevention method. One dose of the MMR vaccine is 93% effective, while two doses are 97% effective…