Li Liming, director of the Chinese Center for Disease Control and Prevention, has resigned for "mismanagement of the Severe Acute Respiratory Syndrome (SARS) virus," the official Xinhua news agency quoted sources as saying.
Four of Li's colleagues were also disciplined, Xinhua said on Thursday. It cited officials with China's Ministry of Health saying the outbreak occurred due to negligence and improper handling of the deadly virus.
The nine infections were all linked to the virology institute.
The laboratory - the National Institute of Virology in Beijing - where the infections occurred was directly under the control of the disease control centre.
Details were not revealed, but state media issued findings from a government report on the latest outbreak which blamed human error.
The report said the outbreak likely occurred because the institute became contaminated, which explained why two victims, both laboratory workers, became infected even though their work did not involve handling the virus, the Beijing News said.
Lab workers may have triggered the infection during experiments inside the institute, the newspaper quoted He Xiong, director of the Beijing CDC, which conducted the investigation, as saying.
The report did not identify any specific procedural errors. However, He also criticised officials at the hospitals where the patients were taken for not reporting about the infections and treating patients in a timely manner.
The outbreak reflected problems with the mechanism for dealing with emergencies and weaknesses in the medical department's procedures, He said, citing insufficient familiarity with how to report cases and forward clinical samples to the appropriate authorities.
Some hospital facilities did not have enough staff, He said. Doctors were not clear about how to report infectious diseases, how quickly they were required to make reports and were insufficiently able to recognise suspected cases, he said.