The 54-year-old top leader of a municipal department headquartered at the Da Nang Administrative Centre, at 24 Tran Phu, Hai Chau District, on Saturday, tested positive for COVID-19. The Da Nang Department of Health has investigated the epidemiological characteristics of this infected woman.

On May 5, the woman had a close contact with a man with confirmed COVID-19 before his positive test came. She was in rush taken to a designated quarantine facility and then tested negative for the virus once via the Gen Expert technique. This is a COVID-19 testing technique appraised by the Ministry of Health in Decision No. 3577/QD-BYT dated August 17, 2020, with specificity and accuracy equivalent to or higher than RT-PCR method.

Her second and third tests using the RT-PCR method conducted on May 7 and 8 respectively came also back negative.

On May 14, the woman showed suspicious symptoms such as fever and cough, which forced her to have her swab samples taken for the fourth test as prescribed.

On May 15, her test conducted via the RT-PCR method by the Da Nang Center for Disease Control (CDC Da Nang) turned positive for the virus. She is receiving treatment at the Da Nang Lung Hospital.

The Da Nang Department of Health affirmed that those who were contacts of this woman with COVID-19 before May 5 are not likely to catch the virus from her.

The woman’s case showed a fact that she became infected days after she had tested negative for the virus thrice.

Actually, after infiltrating a person’s body, the virus can take several days to build up, and in the meantime, there may not be enough virus for a test to detect it. But the person could still be infected or contagious in the interim. A person who tests negative one day might turn positive just a day later, or even an hour later. People can spread the virus in the days before they first start feeling ill, and can also spread the virus even if they never develop symptoms.

Reporting by LE HUNG – Translating by A.T