A medical staff member (L) takes the temperature of a man (R) at the Wuhan Red Cross Hospital in Wuhan on January 25. Hector Retaamal/AFP via Getty Images

Scientists at Imperial College London have estimated the human-to-human transmission rate of the Wuhan coronavirus, saying that each person has infected two to three people, they said in a report on Saturday.

"We estimate that, on average, each case infected 2.6 (uncertainty range: 1.5-3.5) other people up to 18th January 2020, based on an analysis combining our past estimates of the size of the outbreak in Wuhan with computational modelling of potential epidemic trajectories,” the report wrote.

They estimate that transmission needs to be stopped by 60%. “This implies that control measures need to block well over 60% of transmission to be effective in controlling the outbreak,” it added.

When it comes to outbreaks, scientists and public health experts are concerned with how quickly a disease can spread and its mortality rate.

But there is still a lot more to learn about the virus, and scientists have warned against alarmism.

“It is quite easy to get fixed on a particular number but such predicted numbers will vary considerably at this early stage in an epidemic,” Mike Turner, Director of Science, The Wellcome Trust, said in a statement.

“What is becoming clear from several sources though is that there is substantive human to human transmission and that there may well be a lot of people who become infected but have no symptoms or very mild symptoms so don’t need to seek medical attention,” he added.

“This makes it more difficult to put in place effective control measures. A lot of people are working furiously to try and control this epidemic.”

On Sunday, Chinese officials said people can spread the virus before they have symptoms.