Some 17 more people have become infected with a new coronavirus strain which has killed two patients.
The 17 new patients began exhibiting symptoms such as a fever or cough before 13 January, the commission said in a statement.
The World Health Organisation said some of the new cases appear not to be linked to the Huanan seafood market which is believed to be the centre of the outbreak.
The Chinese Center for Disease Control and Prevention, a national level body, issued a large infographic on social media on Saturday, urging people not to believe rumours about the virus and stressing it is not Sars.
The unknown virus is from the same family of coronaviruses that can cause both the common cold and more severe diseases such as Sars and Mers.
Sars killed nearly 800 people globally during a 2002-2003 outbreak that also started in China.
At least a half-dozen countries in Asia and three US airports have started screening incoming airline passengers from central China.
However, some experts have warned the screenings may be ineffective as not enough is known about the virus, such as whether people display symptoms while they are most infectious.
Wuhan will strengthen oversight of large-scale events and reduce the number of public gatherings, state media quoted Chen Yanxin, the city’s deputy mayor as saying on Sunday.
Wuhan officials said since 14 January they are using infrared thermometers at airports, railway stations and other passenger terminals in the city to strengthen screening.
The outbreak has stoked worries globally as many of China’s 1.4 billion people will travel both domestically and overseas during the Lunar New Year holidays beginning next week.
Additional reporting by agencies