Authorities in Vietnam say the new strain of coronavirus responsible for the recent spike in infections is three times more contagious than its predecessor.
Nguyen Thanh Long, the country’s health minister, said on Sunday that those infected with the new strain infect between five and six people on average, Reuters reported.
In contrast, those infected with with the original strain of COVID-19, which arrived in Vietnam in late January, infect on average between 1.8 and 2.2 people, he said.
While the strain is new in Vietnam, it has been seen before in Bangladesh, Britain and Ireland, according to Vietnamese scientists.
The latest cases, which were first found on July 25, marked the end of a 99-day streak without any new cases.
Since then, 204 new cases have been identified, mainly in the region surrounding the coastal city of Da Nang.
Domestic tourists had flocked to Da Nang for their holidays, but 80,000 people were evacuated by plane last week after cases began to rise.
At the time, health authorities said the infections looked to be caused by a different strain of the coronavirus, which Long said had not been seen in Vietnam before July 25, the BBC reported.
There are multiple strains of the novel coronavirus, such as the original D614 strain found in Wuhan, China, last December.
Viruses mutate due to genetic errors over time. However, many scientists argue that mutations don’t necessarily result in viruses becoming more dangerous.
However, some recent studies have suggest that mutated strains of this novel coronavirus spread more effectively than the original.
Marc Choisy, a bio-mathematician from the Oxford University Clinical Research Unit in Hanoi, told The Associated Press that the new strain in Vietnam looks to be more severe.
“One big difference I’ve noticed between this wave and the previous one is that the cases we have right now, a lot of them are severe,” he said.
Long said he could not confirm reports in local media that it was more contagious, or more dangerous, than its predecessor.
As of Monday morning, Vietnam had 621 confirmed infections and six deaths.
The World Health Organization had previously singled out Vietnam for its efforts in containing the virus, but the spike in cases is a somber moment.
Vietnam imposed a strict lockdown and travel ban early on, with the knowledge that the health system could not cope with a mass outbreak in mind.
For example, all 10,000 residents of Son Loi, a town near Hanoi, were placed under lockdown for 21 days in February, despite there being only 16 confirmed cases in the whole of Vietnam at the time, the AP said.