New Jersey health officials issued a warning about a potential measles exposure during the Shakira concert at MetLife Stadium.

Overall, the U.S. has seen more than 1,000 measles cases across 30 states since the beginning of the year, and 11 states with outbreaks — defined as three or more related cases.

Health officials in New Jersey have issued a warning to anyone who attended the Shakira concert at MetLife Stadium in East Rutherford on May 15 after an individual was found to have been infected with...