Pennsylvania Measles Outbreak Sees Breakthrough Cases Among Vaccinated Individuals

Pennsylvania reports four breakthrough measles cases (three adults, one child) from Centre, Jefferson, Lancaster, and Lycoming counties in the ongoing outbreak, with none hospitalized; officials emphasize that breakthrough infections are rare and two doses of MMR provide 97% protection. The outbreak has grown to 676 confirmed cases and 124 hospitalizations across 37 counties with two deaths, and vaccination efforts continue via pop-up clinics and health centers, having administered thousands of MMR doses; high vaccination rates (nearly 93% of kindergarteners fully vaccinated) help shield schools and vulnerable populations.