A Lancaster County resident with measles was at the Lancaster County Courthouse from 10 a.m. to 4:30 p.m. on June 3, prompting the state Health Department to investigate possible exposure.
The person visited the marriage license office but may have moved throughout the building, and officials are contacting potentially exposed staff and community members.
36 measles cases had been reported in Lancaster County by early this week, including 28 since late April; officials said none of those infected had completed the two-dose vaccine series.
Measles can linger in the air for up to two hours after an infected person leaves, while two vaccine doses are 97% effective and about 95% coverage is needed for herd immunity.
The courthouse alert follows a broader regional outbreak that began in Lebanon County and a May 29 notice that a measles-infected Kohl’s employee may have exposed shoppers on four days.