Large-scale nucleic acid testing in Wuhan revealed 300 asymptomatic coronavirus carriers, but no "virulent virus" has been isolated from the throat swabs and sputum samples, according to the municipal health commission on Monday.

The result came just a couple of days after these no-symptom carriers being discovered in the citywide COVID-19 test which covers 9.89 million local residents. 

Scientists in Wuhan Institute of Virology then started to isolate and cultivate the virus in an effort to know its infectiousness.

"Although these asymptomatic patients tested positive on COVID-19 virus, if the viral loads in the samples are very low, then infectious virus cannot be isolated and cultivated," said Zhang Dingyu, deputy director of Health Commission of Hubei Province. Wuhan is the provincial capital.

Zhang also explained that the virus was cultivated to see whether it can infect or kill cultured human cells, so as to know more about its infectiousness.

It turned out viral loads in those samples are extremely low, which suggests Wuhan's asymptomatic carriers are not infectious, experts concluded.

Meanwhile, the personal belongings of the asymptomatic carriers such as toothbrushes, mugs, masks and towels have shown negative COVID-19 testing results in samples collected from the surfaces.

A total of 1,174 close contacts of the 300 cases have also been tested negative for coronavirus.

The result reassured those still living in fear across Wuhan, months after the coronavirus claimed over 3,869 lives. The testing also served as a precaution against a second wave, since a small cluster of infections reemerged in mid-May, ending a month-long record of zero new cases.

Read more: Wuhan is safe, 9.89 million COVID-19 tests show