Expert reveals chances of global ‘Russian plague’ outbreak after reports second person has died

Experts have weighed in on the likelihood of the Russian plague outbreak causing another global pandemic.

A lab technician reportedly died at the Anti-Plague Institute in Siberia's Irkutsk region, now named as Darya Shipilova, 28.

The World Health Organization's Tedros Adhanom Ghebreyesus said on X that she died on October 2 after being hospitalized with severe pneumonia.

Despite this, health experts have said that a global outbreak remains 'extremely unlikely'.

WHO spokesperson Christian Lindmeier announced the organization's initial risk assessment on Tuesday. He said it was ‘moderate to low for Irkutsk’, a low risk for Russia as a whole and ‘very low’ for the WHO European region.

Early media reports suggested pneumonic plague following an alleged accidental lab exposure. Russian health authorities told the WHO that no plague case had recently been registered in the region.

They said identified contacts had been placed under medical observation and tested, and that no high-threat pathogens were detected. Observation of all contacts has now finished.

Reports suggested Shipilova fell ill after either breaking a test tube containing the plague bacterium or taking a field trip to Buryatia, which borders Mongolia and where plague is endemic among wild animals.

The WHO has asked Russia to clarify the cause of her pneumonia, the pathogen that triggered the health measures, and media reports of a second employee with pneumonia of undetermined cause.

Plague is caused by the bacterium Yersinia pestis and comes in three forms: bubonic, pneumonic and septicemic. Bubonic is the most common and is spread by infected fleas, with human-to-human transmission rare.

The bacterium can spread to the lungs, through causing pnemonic plague. Unlike the other forms, it can pass between people through droplets released when someone coughs or sneezes. It is usually fatal without early treatment, and symptoms an begin within 24 hoiurs.

Unlike covid-19, however, it can only spread once symptoms start, and they are severe and obvious.

Zania Stamataki, associate professor of viral immunology at the University of Birmingham, told the BBC: “It's not something that we can miss, where we would see people getting on a plane and travelling around and seeing new infections everywhere.”

In 2025, Piero Olliaro, professor of poverty-related infectious diseases at the University of Oxford, and colleagues published the first randomized controlled trial of bubonic plague treatment, in Madagascar. Two antibiotics, oral ciprofloxacin and an injectable aminoglycoside, were 91% and 92% effective respectively.

In the handful of cases that became pneumonic, 85% of patients survived with swift treatment. “We have two treatments that work very well for bubonic plague,” Olliaro said.

Conditions are also far from those of the Black Death, which killed more than 25 million people in Europe in the 14th century.

Poor sanitation, crowded living and months-long ship voyages helped it spread.

Plague has not gone away, though - it is endemic in rodents across Africa, Asia, South America and the US - and there is an average of seven human cases a year.

A 2017 outbreak in Madagascar caused 2,417 cases and 209 deaths, but it ended without becoming a pandemic.