Russia denies second plague case after Siberian lab worker's death, WHO seeks data

The death and the first reports

Darya Shipilova, a 28-year-old lab worker at the Research Anti-Plague Institute of Siberia in Irkutsk, died on 2 October, according to a timeline given by Deutsche Welle. She last entered the laboratory on 25 September and was hospitalised on 29 September with symptoms of a lung infection. Media reports of her death first emerged on 2 October, and Russian authorities later described the cause as pneumonia of unknown origin. Russian officials said testing did not connect her illness to her work, and Russia has said no dangerous pathogens were found in any of her contacts. Rumours that she contracted pneumonic plague after breaking a test tube spread quickly through Russian media and social networks. Former colleagues and friends rejected that version and said the story smeared her name.

Her mother, Svetlana Shipilova, who works in healthcare, told the Russian outlet Glubina that the broken-tube account was nonsense.

I know the truth. I have to defend myself against foolish acquaintances who believed all of it, the clever ones of course do not believe it.

Quarantine and Russia's position

Irkutsk authorities imposed quarantine on three city hospitals, a children's hospital and a maternity hospital, and isolated about 200 people who had come into contact with her. After nearly 5,000 laboratory tests, authorities released 90 percent of those people from quarantine and said no plague had been confirmed in anyone. Irkutsk's governor, Igor Kobzev, declared on 8 October that anti-epidemic measures had been completed. The governor also said no microorganisms linked to her work had been found in her biological samples. Russia's health regulator said on Thursday that reports of a second person falling ill were false, and Russian authorities describe the situation in the region as calm.

WHO, the rules and the rumours

The World Health Organization asked Moscow for information about the case, but later said the source of the second-case reports was a Russian gossip website that had been cited by Western tabloids. At a press conference on Wednesday, Director-General Tedros Adhanom Ghebreyesus invoked the International Health Regulations, which oblige countries including Russia to share health information that could have international implications. He said:

We don't yet have the full picture of this event.

The WHO said on 7 October that she had died after being hospitalised with severe pneumonia. President Donald Trump has also asked for more information, while Russia insists the situation is not a health emergency.

Plague background and expert view

Plague is caused by the bacterium Yersinia pestis, which rodents and their fleas can transmit to humans. Pneumonic plague can spread between people through respiratory droplets, and Richard Martinello of Yale's medical school says antibiotics must be given at the first signs of infection to work. Between 2019 and 2024, the WHO recorded 1,893 confirmed plague cases in the Democratic Republic of the Congo, the most of any country, while the United States reported 25 cases, according to the CDC.

A CDC report published in October described a July 2025 pneumonic plague death in Coconino County, Arizona. The young male patient had been exposed to two sick domestic cats before falling ill, and 46 people were exposed to him without becoming ill. Colin McKenzie, a microbiologist at the University Hospital Düsseldorf, told Deutsche Welle:

Pneumonia has a certain level of fatal outcomes, even in previously healthy people.

He added that the short incubation period of a few days in the reported timeline could also fit plague, so the dates alone do not rule it out.

Vaccine conspiracy claims

Online posts have linked the death to an Israeli plague vaccine, claiming the two events happened suspiciously close together. The mRNA vaccine was developed by researchers at Tel Aviv University working alongside the Israel Institute for Biological Research, with mouse trial findings published in Advanced Science in April 2025. The university had promoted the research as early as March 2023, long before the woman's death was first reported on 2 October 2026. Russian authorities said there was no evidence she was infected with lab material, and the WHO has requested further information.