WHO Confirms No Plague Cases Detected Following Russian Lab Worker's Fatal Pneumonia

The World Health Organization (WHO) has stated that the exact cause of the pneumonia that led to the death of a laboratory worker at a Russian plague research institute remains unknown, confirming that no cases of plague have been registered.

According to a statement released on Saturday by the United Nations health agency, Russia’s state health regulator reported that tests conducted on the worker, as well as on individuals who had been in contact with her, tested negative for the dangerous pathogens in question. The WHO noted that her contacts continue to show no symptoms, and no additional linked cases of severe pneumonia have been identified.

“Based on the information provided… WHO has not identified evidence of ongoing transmission associated with this event. A key uncertainty remains the absence of a confirmed diagnosis in the deceased laboratory worker,” the agency stated.

The worker fell ill and died under undisclosed circumstances on October 2, an event that led authorities to quarantine approximately 200 people and generated public health concerns across social media. Russian media identified the individual as Darya Shipilova, a 28-year-old laboratory technician at the Irkutsk Antiplague Research Institute of Siberia and the Far East, located in the Siberian region of Irkutsk.

Initial suspicions pointed toward pneumonic plague, a lung infection driven by the bacterium Yersinia pestis, which typically resides in small mammals and their fleas. While the governor of neighbouring Buryatia suggested the woman may have died of the plague, Russia’s health watchdog Rospotrebnadzor formally diagnosed her with pneumonia of unknown aetiology.

Russian authorities reported that the worker was properly vaccinated and that post-mortem tests revealed no microorganisms linked to her professional duties within her body. On Thursday, Russia announced the completion of health checks for all of her contacts and confirmed that all relevant information had been shared with the WHO. Furthermore, a local official reported on October 6 that 60 percent of those initially placed in quarantine had already been released.

In response to media reports concerning a second employee suffering from pneumonia of undetermined cause, WHO chief Tedros Adhanom Ghebreyesus requested clarification from Russia on Wednesday. Russian officials dismissed these reports as false information, while the United States separately urged Russia to maintain transparency.

Global health authorities remain on heightened alert regarding deadly pneumonia cases of unknown origins following the COVID-19 pandemic, which initially emerged from a cluster of fast-spreading respiratory illnesses in China. However, the exact cause of individual pneumonia cases frequently cannot be determined.