WHO seeks additional information from Russia after lab worker's death, reports of 2nd pneumonic plague case

The World Health Organization (WHO) is seeking additional information from Russia on the death of a laboratory worker from suspected pneumonic plague, as well as reports of a second employee with pneumonia of unknown cause, its chief said Wednesday.

Tedros Adhanom Ghebreyesus said in a post on the US social media platform X that the worker at the Irkutsk Antiplague Research Institute died Oct. 2 after being hospitalized with “severe pneumonia.”

He said the WHO has requested additional information to clarify the cause of the worker's severe pneumonia, the pathogen that prompted the public health measures and reports of a second employee with pneumonia of undetermined cause.

"Timely, complete and transparent information sharing" is essential to clarify conflicting reports and accurately assess potential public health risks, he added.

Initial media reports suggested pneumonic plague following an alleged "accidental laboratory exposure," he said.

Russian authorities said no plague cases had recently been registered in Irkutsk Oblast, in response to a WHO verification request under the International Health Regulations.

Authorities told the WHO that an epidemiological investigation was conducted, preventive and control measures were implemented and identified contacts were monitored and tested.

No high-threat pathogens were detected among the contacts, and medical observation of all identified contacts has been completed, according to Russian authorities.

Speaking to reporters in Geneva later Wednesday, WHO officials said the cause of the laboratory worker's death remains unknown and that the information available is insufficient to complete a full assessment of the potential public health risk.

“We don't know exactly how this person died,” WHO's Maria Van Kerkhove said. “We know that she had pneumonia. We know it was a fatal case.”

She said WHO understands that laboratory tests have been carried out but that the causative agent has not been identified. The agency is seeking details on which tests were performed, which pathogens were examined and whether further analysis is underway.

WHO officials said Russia described the illness as “community-acquired severe pneumonia of unknown etiology,” which would indicate that authorities believe the infection did not originate in the laboratory.

Van Kerkhove, however, said WHO still wants to establish both what caused the infection and how the worker contracted it.

The agency is also seeking more information about conditions at the facility, including what pathogens the worker handled, the protective equipment used and whether any laboratory incident occurred.

WHO officials stressed that an initial risk assessment had been based on reports of suspected pneumonic plague, a disease whose risks are well understood. But with the pathogen now undetermined, they said there is not enough information to assess the risk of further spread.

Asked whether Russia should have provided more information, Van Kerkhove said: “The simple answer is always yes.”

“We need transparent and timely reporting from all of our member states,” she said, stressing that such information is necessary for WHO to assess risks and alert other countries when needed.

WHO has offered technical support on infectious diseases and laboratory biosafety and biosecurity and said it could send experts if requested.