Coronavirus patients with mild symptoms are likely to be extremely contagious soon after being infected with the bug, a new study says.

Researchers revealed in the study published in the medRxiv journal that people with mild cases emit high rates of the virus during the first five days after infection, the Telegraph reported.

The study, which has not been peer-reviewed, looked at nine patients who tested positive and determined those with just cold symptoms could be very contagious.

“You don’t have to be seriously ill to pass the virus on to other people,” Dr. Clemens Martin Wendtner, the study’s co-author, told the Telegraph.

The period when these patients are most infectious — known as “peak shedding” — shows the virus being emitted at a rate 1,000 times higher than during the same time for people infected with SARS, the report said.

“This is in another dimension compared to SARS,” said Wendtner, who is a Ludwig-Maximilians University professor.

Wendtner said the findings suggest that large gatherings — such as conferences and sporting events — should be canceled, since the virus can spread even in patients who don’t appear to be ill.

“This virus is spreading even in very asymptomatic patients,” Wendtner told the outlet.

Jonathan Ball, a professor of molecular virology at the University of Nottingham who wasn’t involved in the research, said the study could indicate that the “bulk of people transmitting the disease” are mild cases.

“Therefore the fact the study shows fairly high levels of virus replication and shedding in individuals likely to have symptoms of a cold, rather than a lower respiratory chest infection such as a cough or shortness of breath, is significant in terms of public health advice,” Ball told the Telegraph.

Worldwide, the deadly bug has spread to more than 115,000 people since it first broke out in December in Wuhan, China.