WHO unsure what caused pneumonia that killed plague-lab worker in Russia - Reuters

A laboratory worker at an anti‑plague research centre in Siberia fell ill and died on 2 October, prompting a public health response that included the quarantine of roughly 200 people who had been in contact with the employee. The circumstances surrounding the illness and death have not been disclosed in detail.

The World Health Organization (WHO) said on 10 October that it still does not know what caused the pneumonia that led to the worker’s death. The organization noted that no case of plague has been registered in connection with the incident.

According to the Russian state regulator, tests performed on the deceased worker and on individuals who had been exposed to her were negative for the high‑threat pathogens that were examined. The regulator also reported that none of the contacts have shown symptoms of illness.

In its statement, the WHO said that, based on the information provided, there is no evidence of ongoing transmission linked to the event. A key uncertainty remains the absence of a confirmed diagnosis for the deceased laboratory worker.

Russian authorities have stated that the worker was appropriately vaccinated and that investigations did not find any microorganisms in her body that could be linked to her laboratory work.

Health officials worldwide have been particularly vigilant for fatal pneumonia cases of unknown origin since the COVID‑19 pandemic, which began with a cluster of rapidly spreading respiratory illness in China. The incident has generated public health concerns on social media, although no further severe pneumonia cases have been identified.