Talking to VnExpress on May 24, Dr. Nguyen Van Vinh Chau, Director of the Hospital for Tropical Diseases in Ho Chi Minh City, said that it is currently impossible to confirm that the chain of infection at O Thanh noodle shop is related to outbreaks in Da Nang.
`The health sector will combine epidemiological information with large-scale gene decoding, comparing it with virus genome information collected from the provinces to build a ‘phylogenetic tree’ to explain the origin of the strain.
Phylogenetic tree, that is, when decoding the virus gene, computer software will arrange genomes with nearly similar structures next to each other, with more different structures far apart.
According to epidemiological investigation, this restaurant located in District 3 is quite famous, sometimes business groups from Hanoi or the Central region come to eat.
The second hypothesis is that this strain may have entered Ho Chi Minh City from Da Nang and Ha Nam some time ago, silently spreading the disease in the community from asymptomatic people with Covid-19.
Third, we cannot rule out the possibility that this strain originated in the Northern provinces, a silent `remnant` from the time `patient 1660` – a 28-year-old young man in Hai Duong – discovered the disease in the city.
At a recent meeting of the Ho Chi Minh City Covid-19 Steering Committee, Director of the Ho Chi Minh City Center for Disease Control (HCDC) Nguyen Tri Dung said that the source of infection in District 3 has not yet been found. `The source of infection is not always found.`
HCDC is continuing to investigate more contact cases, epidemiological schedules… to find the source of infection.
Mr. Ton That Thanh, Director of Da Nang CDC, said that the three patients 4780, 4781 and 4782 are not epidemiologically related in Da Nang.
The results of virus gene sequencing, restaurant owner O Thanh and one of her two children, recorded the British variant B.1.1.7.
This British variant is circulating in Da Nang and Ha Nam, and is currently spreading to the central provinces.
Recently, Ho Chi Minh City Hospital for Tropical Diseases in collaboration with Da Nang CDC decoded 5 nCoV genomes from patients currently in Da Nang, the results also belonged to the British variant B.1.1.7.
In addition to the British variant, Ho Chi Minh City is also recording the Indian variant B.1.617.2 in `patient 4583` – a woman living in District 7 and `patient 4514` – a young man living in Thu Duc City.
`This is the first time Ho Chi Minh City has recorded the simultaneous circulation of both strains, which are believed to be able to spread faster than previous nCoV strains, in cases in the community,` Dr. Chau said.
Both of these variants have appeared in a number of provinces and cities across the country, causing Vietnam to have a very complicated and overlapping picture of community transmission.
According to Dr. Chau, structural mutations can make the virus more `evil` in the process of invading the human body, such as penetrating cells more easily, destroying cells faster, and avoiding antibodies created from the virus.
Vietnam needs to strictly prevent the spread of the virus from sick people to healthy people, ensuring from quarantine after entry to compliance with `5K` in daily activities.
Vietnam is in the midst of an epidemic outbreak.
Covid-19 testing at Ho Chi Minh City Tropical Diseases Hospital.
Le Phuong – Anh Thu – Van Dong
