WHO says cause of Russian laboratory worker’s fatal pneumonia remains unknown

The World Health Organization said on 10 October that the cause of severe pneumonia that killed an employee of the Irkutsk Anti-Plague Research Institute of Siberia and the Far East in Russia’s Irkutsk Oblast remains unconfirmed. The worker was hospitalised in September and died in October, while Russian authorities and WHO reported no evidence of continuing transmission linked to the event.¹

Diagnosis remains unresolved

Russian authorities confirmed the death after the employee was admitted to hospital with severe pneumonia. Following testing that did not identify plague or several other high-threat pathogens, the fatal illness was classified as “pneumonia of undetermined etiology”, according to WHO. The agency said it could not confirm the diagnosis or identify the causative agent from the information available.¹

Media reports had raised the possibility of pneumonic plague after a workplace laboratory exposure. Russian authorities said, however, that no plague case had recently been registered in Irkutsk Oblast. WHO said a laboratory-associated exposure could not be entirely ruled out, while also reporting that Russian authorities had found no laboratory biosecurity incident.¹

Testing and contact monitoring

Russian authorities reported carrying out more than 5,500 laboratory tests without finding high-consequence or dangerous pathogenic microorganisms. The identified contacts of the deceased worker completed medical observation without developing symptoms and tested negative for the pathogens being investigated, WHO said. Observation of those contacts was subsequently discontinued.¹

Testing among contacts did identify two cases of COVID-19, three rhinovirus cases and one Haemophilus spp. case, according to WHO. The deceased worker had not travelled outside Irkutsk Oblast in the two weeks before symptoms began. Quarantine was put in place at the hospital where the patient received treatment, but not at other healthcare facilities.¹

WHO assessment

WHO contacted Russian health authorities in October under the International Health Regulations to seek verification and further information. A regional sanitary and anti-epidemic commission also met in October and approved response measures, while Rospotrebnadzor approved an operational action plan, according to the information supplied to the agency.¹

WHO said it found no signs that transmission was continuing in connection with the death. It added that it could not independently judge whether the contact-monitoring measures were sufficient because the diagnosis remains unconfirmed. The agency said it would continue monitoring the event and assess any public-health implications.¹

WHO does not recommend travel or trade restrictions in connection with the event. The Straits Times similarly reported that WHO remained unsure what caused the pneumonia that killed the laboratory worker.¹²