WHO: Cause of death of Russian Siberian laboratory worker still unknown

The WHO said Russia's national regulatory agency reported that tests of the laboratory staff and their contacts showed negative results for high-risk pathogens. The contacts are currently asymptomatic, and no other related severe pneumonia cases have been found.

"Based on the information provided...WHO has found no evidence of sustained transmission associated with this event. A key uncertainty is that the cause of death of the deceased laboratory worker has not yet been confirmed," the WHO said in a statement.

The staff member died on October 2, and the specific circumstances of his illness and death have not been announced. The incident prompted authorities to quarantine about 200 people and sparked public health concerns on social media.

This is the first time that the WHO has issued a detailed "disease outbreak news" report on the matter since the case was exposed, and called for continued investigation.

"More clinical, epidemiological and laboratory information, including diagnostic confirmation of the deceased laboratory worker, is needed to increase the confidence of the assessment," WHO said.

Since the outbreak of the new coronavirus, health officials around the world have been on high alert for cases of fatal pneumonia of unknown cause. However, the cause of many pneumonia cases is ultimately unidentified.

Russian authorities stated that the laboratory worker who died of pneumonia had been vaccinated as required, and no microorganisms related to his work were found in his body.

Russia said on Thursday that it had completed health checks on all contacts of the staff member and had provided complete information to the WHO in accordance with established procedures. Russia also denied the occurrence of a second similar case.