A Learning Support Educator working at a summer school in Luqa was among patients who tested positive for COVID-19 after attending an all weekend pool-party.
The LSE returned to work following the party but exhibited no virus symptoms while she was in contact with three Skolasajf classrooms, health authorities said on Monday.
The school's administration has started contacting parents of children who attend the school to get tested for the virus.
Meanwhile, health authorities are carrying out the necessary contact tracing.
The case is one of 17 that have emerged following the Hotel Takeover pool party, where revellers were in close contact over the weekend. The one new case of COVID-19 detected today was also linked to that cluster.
The incident has sparked growing calls for a ban on mass events.
Two cases traced to Dingli school
The Luqa case is one of three recent COVID-19 cases to be traced to local schools, with two further imported cases of COVID-19 traced to students attending a Dingli summer school.
Both were students who had returned to Malta after travelling abroad and gone back to school before testing positive for the virus.
Earlier in the day, the Health Authorities advised people who had attended feast celebration in Sta Venera to contact 111 and get tested, as one attendee who went to the band club and attended the feast march had tested positive for coronavirus.