Her first test result arrived as positive Tuesday night after the city tracked down 59 people who have had contact with the 35-year-old man who lives in Thu Duc City, works at an auditing company District 3, and has tested positive at least twice.
According to the city's Centers for Disease Control and Prevention, the woman, 34, lives in Tan Kieng Ward of District 7 and also works at the auditing company.
She had visited northern Hai Phong City, a coronavirus hotspot, from April 24 to May 5.
She flew back to HCMC on May 5 on Vietnam Airlines flight VN1179 and ran a fever three days later. She bought medicine to treat herself and did not have her health checked at any healthcare facilities.
She took sick leave for three days after that and returned to work on May 11.
The city is tracing down passengers on the flight and people that have come into close contact with her.
The Thu Duc man has not been recorded by the Health Ministry as a Covid-19 patient.
He had visited Vinmec Hospital on Monday for symptoms including fever, coughing and sore throat and then his samples were taken for testing.
His mother, wife and two children who live with him have tested negative at least once.
For the ongoing Covid-19 wave that broke out in Vietnam three weeks ago, the health ministry has confirmed just one patient in HCMC. No new local transmission has been linked to the city for 75 days.
Nationwide, the new wave has seen 1,473 cases recorded in 28 cities and provinces.