One group has been found in Covid-19 patients entering Vietnam from Wuhan in China, and the other in those who came from Europe, said Le Thi Quynh Mai, deputy director of the institute.

"There is a clear difference," Mai said, adding that this evolution process occurs naturally when the virus jumps from one organism to another.

"The virus will keep changing. We will follow the process closely," she said.

The institute has not yet confirmed whether there are differences in virulence between the two virus groups, Mai said.

Scientists at the institute first succeeded in culturing and isolating the novel coronavirus in early February, which will serve as a basis for the development of a future vaccine.

Vietnam has also produced its own Covid-19 test kits that provide quicker results and are easier to use than those used by the U.S. Center for Disease Control and the World Health Organization, according to the Ministry of Science and Technology.

The country has confirmed 241 Covid-19 cases so far, with only one new case recorded since Sunday, less than a week into the fortnight long social distancing campaign announced by Prime Minister Nguyen Xuan Phuc, which calls for people to stay home and does not allow public gatherings of more than two until April 15.

Of the 150 Covid-19 active cases in Vietnam at present, half have tested negative at least once.

Globally, the Covid-19 pandemic has claimed more than 69,500 lives.