TAIPEI (Taiwan News) — Six air cargo pilots have tested positive for COVID-19 antibodies, and the number of people in the China Airlines cluster infection has risen to 11.

During a press conference on Tuesday (April 27), CDC Director-General Chou Jih-haw (周志浩) announced that since an Indonesian cargo pilot that flies for China Airlines tested positive for COVID-19 while in Australia, the center has launched an epidemiological investigation into 1,272 pilots. Currently, 934 have been tested for serum antibodies, with 925 coming back negative and six positive, and three are undergoing testing.

Chou said that of the six pilots who tested positive for antibodies, three — cases 151, 177, and 1,105 — had previously been diagnosed with COVID-19. The other three are Taiwanese citizens in their 40s, including two men and one woman.

The three underwent coronavirus tests on April 22, 24, and 25. The nucleic acid tests came back negative, and they were negative for IgM antibodies but were all found to be positive for IgG antibodies.

Chou said that for all three previously undiagnosed but seropositive cases, an investigation into the flight records will be conducted. He also said accompanying crew members will undergo an epidemiological investigation, and close contacts will be identified and tested for the virus and antibodies.

Also on Tuesday, the CECC announced that the wife of the Indonesian pilot has tested positive, bringing the air cargo cluster infection to 11 people.