Taipei, Aug. 9 (CNA) Despite the emergence of positive cases in an ongoing mass testing program for COVID-19 antibodies in Changhua County, no community outbreak has been seen, the Central Epidemic Command Center said Sunday.

The positive cases reflect the possibility of hidden domestic cases, but also mean that the situation can be controlled as evidenced by the lack of an outbreak of locally transmitted cases, said Health Minister Chen Shih-chung, who also heads the CECC, at a press conference in Taipei.

Taiwan has not recorded any domestic cases of COVID-19 since April 12, CECC data shows.

"However, no domestic cases does not equate to no risk. What we want is to be in control of the risks," Chen said.

Taiwan has a total of 10 cases where the source of infection has not been identified, in addition to an outbreak on board a navy ship, and other cases involving foreign nationals who tested positive on returning to their home countries, Chen said.

The case of a Belgian technician who was confirmed to be positive Aug. 1 after taking a test to return to his home country is still under investigation, Chen said.

It may be possible that some of the cases with unknown sources are related to hidden domestic cases but they have not caused large community outbreaks, Chen said.

"As such, we think that the risks involved are controllable," Chen said.

Chen also said he is looking forward to seeing the complete report from National Taiwan University's (NTU's) College of Public Health in collaboration with Changhua County government, which has so far found reactions in all four trget groups totaling about 3,000 people.

The groups include people who contracted the SARS-CoV-2 virus, others who came into contact with them, those who had been in home isolation or quarantine at some stage over the past few months, as well as healthcare practitioners in Changhua, according to NTU.

"I believe when the complete report comes out it will provide a good reference," Chen said.

Chen Hsiu-hsi, a professor from the college, said the exact infection rate is still being calculated, with further results to be disclosed on Aug. 25.

The total number of confirmed cases in Taiwan climbed to 480 Sunday, with 388 classified as imported, according to CECC data.