May 6, 2004 (CIDRAP News) Neither of two researchers who apparently contracted SARS (severe acute respiratory syndrome) in a virology laboratory in Beijing worked directly with the SARS virus, which complicates the problem of determining how they acquired it, the World Health Organization (WHO) says.
"Neither is known to have conducted research using the live virus, suggesting some other source of infection within the laboratory or possibly elsewhere," the WHO said in a statement dated yesterday. Others at China's National Institute of Virology were working with the virus in February and March, the statement said.
A joint WHO-Chinese investigative team visited the virology lab Apr 30 and May 4, the agency said. "Initial findings indicate that the investigation will be complex, as no single infectious source or single procedural error appears likely to explain infection in the two researchers," the statement said.
A 26-year-old female postgraduate medical student became ill Mar 25 after working in the virology lab for 2 weeks in mid-March. In addition, a 31-year-old man who works in the lab fell ill Apr 17. Both cases were eventually confirmed to be SARS. The other seven cases in the current outbreak have all been traced back to the student researcher.
In other recent developments, another SARS patient, a 20-year-old nurse surnamed Li, was released from a Beijing hospital May 4, according to a report yesterday by Xinhua, China's official news agency. Li fell ill shortly after treating the student researcher in a Beijing hospital from Mar 29 to Apr 2. Five people who had contact with Li, including three of her family members, subsequently contracted SARS.
The Xinhua report said the other seven case-patients were in stable or good condition yesterday. (The second case-patient in the outbreak, the mother of the student researcher, died Apr 19.)
Reuters reported that at least 159 people were released from quarantine in two Beijing hospitals today. They had been quarantined for about 2 weeks after coming in contact with Li, the story said. But hundreds of others remained in quarantine, the report said.
The WHO statement said more investigation is needed to track down the source of infection in the virology lab and ensure that proper steps have been taken to minimize the risk of further SARS cases. Chinese investigators took many samples from the lab, and the WHO SARS lab in Hong Kong is analyzing them, officials said.
The WHO also said the National Institute of Virology was closed Apr 23 and most of its staff were quarantined for medical observation. However, a few staff members have stayed in the facility to continue essential experiments and care for lab animals, the agency said.
Meanwhile, the US Centers for Disease Control and Prevention (CDC) is contacting labs that have samples of the SARS virus to make sure they are using appropriate safety precautions, according to another Reuters report today. A CDC spokesman told Reuters the agency had sent samples of the virus to 56 labs, most of them in the United States.
The WHO has recommended that research on the live SARS virus be done only in labs rated at biosafety level 3 or higher.
May 5 WHO statement