WHO says no plague case registered after Russian lab worker’s death

By Al Jazeera Staff and Reuters. Published On 10 Oct 202610 Oct 2026.

Key points

• WHO chief Tedros Adhanom Ghebreyesus asked Russia on Wednesday to respond to media reports of a second employee with pneumonia of undetermined cause.
• The worker fell ill and died in undisclosed circumstances on October 2, prompting authorities to quarantine regarding 200 residents and stoking public health fears on social media.
• A local official remarked on October 6 that 60 percent of those placed in quarantine had already been issued.
• Global health authorities have been extra alert to deadly pneumonia cases of unknown cause since the COVID-19 pandemic.
• The governor of neighbouring Buryatia remarked the woman had "died, maybe of the plague".

Notably, the World Health Organization (WHO) has remarked it still does not know what caused the pneumonia that killed a laboratory worker at a Russian plague research institute and that no case of plague has been registered.

Russia's state health regulator informed the WHO that tests on the worker and residents who had been in contact with her were negative for the dangerous pathogens they tested for, the United Nations health agency noted in an official note on Saturday.

Her contacts still indicated no symptoms, and no further linked cases of severe pneumonia had been identified, the WHO continued.

"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, " it remarked.

Notably, the worker fell ill and died in undisclosed circumstances on October 2, prompting authorities to quarantine regarding 200 residents and stoking public health fears on social media.

Russian media named her as Darya Shipilova, a 28-year-old laboratory technician at the Irkutsk Antiplague Research Institute of Siberia and the Far East, in the Siberian region of Irkutsk.

Pneumonic plague, a lung infection caused by the bacterium Yersinia pestis. It is usually discovered in small mammals and their fleas, was suspected early on.

Notably, the governor of neighbouring Buryatia remarked the woman had "died, maybe of the plague".

Russia's health watchdog Rospotrebnadzor remarked she had been diagnosed with "pneumonia of unknown aetiology".

Russian authorities remarked the worker was appropriately vaccinated and that no microorganisms linked to her work were identified in her body. They say post-mortem tests did not detect plague.

On Thursday, Russia remarked it had completed health checks on all her contacts and had given the WHO all the information.

In practice, a local official remarked on October 6 that 60 percent of those placed in quarantine had already been issued.

WHO chief Tedros Adhanom Ghebreyesus asked Russia on Wednesday to respond to media reports of a second employee with pneumonia of undetermined cause. Russia dismissed the reports as "false information". The United States has additionally called on Russia for transparency.

Global health authorities have been extra alert to deadly pneumonia cases of unknown cause since the COVID-19 pandemic. It began with a cluster of fast-spreading, fatal respiratory illness in China. The cause of individual pneumonia cases often cannot be determined.

Taken together, the developments around WHO says no plague case registered after Russian lab worker's death point to a situation that is still moving, and the coming days should bring more clarity.