A maintenance worker walks out of the headquarters of Russia's consumer and health watchdog Rospotrebnadzor in Moscow on Oct. 5, 2026. (Credit: Igor Ivanko / AFP)
Russia's health regulator said on Wednesday there were no risks of an epidemic breaking out in Siberia after a plague institute worker there died, as the World Health Organization pressed Moscow for more information about her cause of death.
Russian authorities say the 28-year-old laboratory worker died on Friday from pneumonia of an as-yet unestablished origin, in a case that has prompted international concern, including from U.S. President Donald Trump. Around 200 people were initially placed in quarantine.
Global health officials — as well as the world's media — have been particularly alert to pneumonia cases of undetermined cause since the COVID-19 pandemic, which began with a cluster of fast-spreading fatal respiratory illness in China.
However, the cause of individual pneumonia cases can often not be determined. The WHO estimates the risk of the Russia incident to the general public to be low based on currently available information.
Rospotrebnadzor, Russia's health watchdog, said in a statement on Wednesday it was winding down precautionary measures it had put in place after concluding there was no risk of an epidemic and that it had shared its latest information with the WHO.
No cases of plague had been detected among anyone who had come into contact with the deceased worker, Darya Shipilova, it said, and 90% of those placed in quarantine had been released after nearly 5,000 lab tests had failed to detect any dangerous pathogens.
It said Shipilova had been vaccinated and had therefore been "immune to the dangerous infections with which she worked." It did not say though what had caused the pneumonia which killed her or how she fell ill.
WHO calls for more information
Tedros Adhanom Ghebreyesus, the director-general of the WHO in Geneva, said earlier on Wednesday that his organization needed more information from Russia to understand what had happened.
"WHO has requested further information to clarify the cause of the severe pneumonia, the pathogen that prompted the public health measures, and media reports of a second employee with pneumonia of undetermined cause," he said on X.
"Timely, complete and transparent information sharing under the International Health Regulations is essential to clarify conflicting reports and enable an accurate assessment of potential public health risks."
Kremlin criticizes 'false information' in media
The Kremlin said Russia had properly informed the WHO about the incident in line with established procedures.
When asked about the WHO's request to respond to reports about a second person in Siberia allegedly falling ill, Kremlin spokesman Dmitry Peskov urged caution when it came to using media reports as a reference for what was happening.
"There is a great deal of media coverage, and the vast majority of what the media are reporting about this situation is false information," said Peskov.
He advised the media and others to rely on information provided by the health regulator. It did not immediately respond to a Reuters comment request on Wednesday about the WHO's questions.
Exact cause of death remains unknown
Some Western media outlets have reported — citing unnamed "Russian media" — that a second person in Siberia had died, saying they had died of plague.
Reuters was unable to find any such stories in Russian media or any evidence that a second person in Siberia had died although some bloggers on social media were making — without evidence — such assertions.
Contacted by Reuters, the WHO said it had nothing further to add on the matter beyond what Tedros — who was due to give a press conference later on Wednesday — had already posted on X.
Tedros' call for more information echoed that of US Secretary of State Marco Rubio, who has also said Moscow needs to share more information about the incident.
Pneumonia, a lung infection, can have a variety of causes including plague as well as other bacterial infections or viral respiratory diseases, such as flu or COVID-19.