The World Health Organization (WHO) is investigating the circumstances surrounding the death of a 28-year-old employee of the Irkutsk Research Anti-Plague Institute, who died at a hospital in the city of Shelekhov.

The researcher died from severe pneumonia. Earlier media reports raised the possibility that she may have contracted pneumonic plague following an incident at a laboratory, according to WHO Director-General Tedros Adhanom Ghebreyesus' message on X.

Ghebreyesus said Russian health authorities had informed the organization that no cases of plague had been officially registered in the Irkutsk region.

Russian authorities also reported that an epidemiological investigation had been completed. People who had been in contact with the researcher were placed under medical observation and tested, with no dangerous pathogens detected among them.

However, the WHO has sent an additional request to clarify the cause of the acute pneumonia, identify the pathogen that prompted the response from sanitary authorities, and obtain information about a second employee who reportedly developed symptoms.

Ghebreyesus stressed the importance of timely and transparent information sharing and said the WHO had offered Russian authorities expert assistance.