Nearly 5,000 laboratory tests were conducted during the quarantine period, and no dangerous pathogenic microorganisms were detected, Kobzev said in a Telegram post. He stated that no emergency situations involving pathogens had occurred at the institute, and that the deceased worker had been vaccinated and possessed immunity to the infections she handled.
The 28-year-old laboratory assistant at the Irkutsk Anti-Plague Institute died at Shelekhovskaya District Hospital overnight into October 2. Authorities subsequently isolated around 200 people. The outlet Lyudi Baikala reported that several hospitals in Irkutsk were placed under quarantine, and that workers at the Irkutsk Aluminum Plant in Shelekhov were required to wear masks.
Accounts of the cause of death conflict. Lyudi Baikala reported that on September 25 the laboratory assistant broke a test tube containing the causative agent of pneumonic plague in the laboratory. The head of Buryatia, Alexei Tsydenov, confirmed that the woman died of plague but denied she was infected during a work trip to the republic. Rospotrebnadzor, Russia's consumer health and welfare watchdog, cites the cause of death as "pneumonia of unspecified etiology" and asserts that microorganisms linked to the employee's work were not found in her biomaterial. Epidemiologist Mikhail Favorov said on the air of "Bild in Russian" that a negative result does not mean the absence of plague: in fulminant cases, the live bacterium can be isolated in only 10-30% of cases.
The divergence also extends to how international organizations assess the situation. Kobzev stated that the WHO "publicly confirmed the absence of risks to public health." However, WHO Director-General Tedros Ghebreyesus said at an October 7 briefing that the organization did not yet have a full picture of what happened and requested additional information about the causative agent of the severe pneumonia. Rospotrebnadzor says it sent the WHO "complete and exhaustive information" under the International Health Regulations, and that the WHO confirmed receipt of this information.
Rospotrebnadzor and Governor Kobzev maintain the death was from pneumonia of unspecified etiology with no emergency situations at the institute; Lyudi Baikala reported a broken test tube containing the plague pathogen, and Buryatia head Tsydenov confirmed death from plague. Kobzev says the WHO confirmed the absence of risks, while Ghebreyesus stated there was no full picture and that additional data had been requested. Rospotrebnadzor also called reports of a second infected institute employee a fake.
Kobzev separately thanked security services and medical workers for "practically round-the-clock work under conditions of information pressure." According to The Wall Street Journal and CNN, the United States sent Russia a demarche over the concealment of data on the laboratory assistant's death, and Donald Trump said he planned to discuss a possible plague outbreak with Vladimir Putin.