Hanoi's chairman Nguyen Duc Chung said on Monday a resident in the capital city has tested positive for novel coronavirus disease (COVID-19) 23 days after visiting a major hospital that is Vietnam’s largest known cluster of infections to date.
The patient is one of two new COVID-19 cases mentioned by Chung as he chaired a meeting of the city’s steering committee on prevention and control of the disease on Monday morning.
According to Chung, the 47-year-old patient from Me Linh District visited the Department of Allergy and Clinical Immunology at Bach Mai Hospital in Dong Da District on March 12.
The medical center of Me Linh District sampled the patient on April 4, after at least 44 COVID-19 patients in Vietnam had been linked to Bach Mai Hospital.
The sample was sent to the Hanoi Center for Disease Control for testing, with the result coming back positive on Sunday.
“It had been 23 days since [the patient] last came to Bach Mai Hospital for treatment and test results have now returned positive [for the virus],” Chung emphasized at Monday’s meeting, claiming that the patient stayed inside her home without any social interaction between the hospital visit and her positive result.
It is unclear from Chung’s statement whether the patient was tested between March 12 and April 4.
After citing the case as an example, Chung warned meeting attendees of infections with an incubation period of more than 14 days.
He claimed that there has been a case in South Korea that did not test positive for the virus until after 27 days from suspected exposure and one case in the central Chinese city of Wuhan, where the virus first emerged, that did not test positive until after 39 days.
The average time between exposure and testing positive in the U.S. is 22.5 days, Chung said, without elaborating.
According to the U.S. Centers for Disease Control, the incubation period, or the time from exposure to development of symptoms, of the novel coronavirus ranges from two to 14 days.
Meanwhile, the World Health Organization (WHO) said that the incubation period for COVID-19 is on average five to six days, and can be up to 14 days.
According to Vietnam’s Ministry of Health, the incubation period for COVID-19 is 2-14 days, with 5-7 days being the average.
The other case mentioned by Chung at Monday’s meeting was detected at a centralized quarantined camp at a campus of FPT University in Hanoi.
The patient, 35, from Cam Quang Commune in Cam Xuyen District, located in the north-central province of Ha Tinh, was one of the passengers on board a flight from Moscow that arrived in Hanoi on March 25.
The patient was sampled for the first time upon their arrival with results turning out negative for the virus.
The patient was sampled again on Sunday with results returning positive on Monday morning.
Hanoi has reported 107 cases of COVID-19 infection, the highest number among all of Vietnam’s provinces and cities, according to numbers pooled by Tuoi Tre (Youth) newspaper.
The infection cases in Hanoi can be divided into three groups, Chung said, including imported cases quarantined upon arrival, cross infections detected in the community, and patients linked to Bach Mai Hospital.
Vietnam has so far confirmed 245 COVID-19 patients, 95 of whom have recovered and been discharged from the hospital, including 38 recoveries in Hanoi.
No death related to the disease has been recorded in the country.