DOVER, Delaware — Health officials in Delaware are urging teenagers who participated in senior week activities at the state’s beaches to get tested for the coronavirus after several participants tested positive.

The state Division of Public Health said Saturday that at least three teens staying at a rental unit in Dewey Beach tested positive for the virus. More than a dozen teens were staying there at the time.

The health department says the teens attended large parties in nearby Rehoboth where more than 100 attendees might have been exposed to the virus.

Health officials did not specify the time of the teenagers’ stay in Dewey. They are trying to trace the infected teens’ potential contacts.

Senior week is a longstanding tradition in which graduating high school seniors in Delaware and Maryland celebrate at the beaches in those states, usually unchaperoned.