Someone who attended the recent Shakira concert in New Jersey may have been exposed to this wildly contagious disease.

Shakira fans who attended the singer’s Thursday show at MetLife Stadium are being warned by health officials that at least one concertgoer had the measles.

A measles exposure could happen whenever, wherever. Thousands of concertgoers may have come in contact with the virus at a Shakira show at the MetLife Stadium last Thursday, according to an alert from the New Jersey Department of Health this week.