The 21 people who came in close contact with a man confirmed last weekend to have Middle East Respiratory Syndrome(MERS) have all tested negative for the highly infectious disease. 

The Korea Centers for Disease Control and Prevention made the announcement in a briefing on Friday, or seven days after the first case in over three years was reported.

The agency had tested the 21 people on Thursday, after the average six-day incubation period for MERS had passed. The agency plans to test them again next Thursday, before the maximum incubation period ends. 

The incubation period for MERS ranges from two days to 14 days.

The results come after eleven others who came into contact with patient zero and showed symptoms of fever and coughing all tested negative for the disease.