The World Health Organization (WHO) says it still cannot confirm what killed an employee of the Irkutsk Antiplague Research Institute in Siberia, whose death on October 2 triggered hospital quarantines, the testing of roughly 200 contacts and media reports of a laboratory plague exposure. In a Disease Outbreak News notice published October 10, WHO said Russian authorities attribute the death to pneumonia of undetermined cause, that no high-threat pathogen was found in the patient or her contacts, and that “a laboratory-associated exposure therefore cannot be fully excluded at this stage.”
According to the WHO notice, the agency learned of the death through media reports on October 2. The employee had been hospitalized on September 29 with severe pneumonia. Russia’s National IHR Focal Point confirmed the death, said no plague cases had recently been registered in Irkutsk Oblast, and said that, contrary to media reports, no laboratory biosecurity incident had occurred. The hospital where the patient was treated was placed under quarantine.
WHO contacted Russian health authorities on October 3, 5, 6 and 7 to verify the reports, including a purported second case, invoking the verification articles of the International Health Regulations (IHR) and requesting further information on October 7 and 8. It also offered support on high-threat pathogens and laboratory biosafety and biosecurity.
Russian authorities told WHO on October 6 that the patient initially had symptoms consistent with an acute respiratory viral infection and that, after tests for several high-threat pathogens came back negative, the death was attributed to pneumonia of undetermined etiology. Testing of the patient and contacts on October 7 and 8 covered influenza, SARS-CoV-2 and other respiratory and bacterial pathogens, including plague and streptococcus. Among contacts, laboratories found two COVID-19 infections, three rhinovirus infections, one Haemophilus infection and other opportunistic infections, but no high-threat pathogens. The employee had been vaccinated against the pathogens she worked with and had not traveled outside Irkutsk Oblast in the two weeks before falling ill.
Contacts were monitored for seven days with daily laboratory testing; all remained asymptomatic, and monitoring was discontinued on October 9. Five Rospotrebnadzor organizations ran more than 5,500 laboratory tests using bacteriological, biological, mass spectrometric and molecular genetic methods, none of which detected a high-consequence pathogen, and two independent inspections found no biosafety or biosecurity incident at the institute, according to the notice.
Why it matters
WHO’s own assessment turns on what is missing. The absence of a confirmed diagnosis is the key uncertainty, the agency wrote, and it cannot independently judge whether the seven-day monitoring period was long enough to rule out every plausible cause. Because the worker handled high-consequence pathogens, WHO said its confidence in the assessment is limited and that confirming the diagnosis would improve it. At the same time, it said it “has not identified evidence of ongoing transmission associated with this event” and does not advise travel or trade restrictions.
The episode is also a test of how the IHR work in practice. At a media briefing on October 7, WHO Director-General Dr Tedros Adhanom Ghebreyesus said Russia had replied to WHO’s October 3 request by reporting no recent plague case in the oblast and about 200 contacts in quarantine, and that WHO was still seeking laboratory details, the reasons for the public health measures, the health status of contacts and verification of reports of a second employee with pneumonia. “Timely, complete and transparent information sharing under the International Health Regulations is essential,” he said.
What ECDC says
The European Centre for Disease Prevention and Control (ECDC) carried the event in its weekly threats report for October 10 to 16. It noted unverified media accounts that the deceased was a 28-year-old laboratory technician who broke a tube containing Yersinia pestis, the plague bacterium, on September 25, and stressed that “these reports have not been confirmed.” Russian media put the number of contacts under observation at 189 to 200, including institute staff, health workers, ambulance personnel and hospital patients. ECDC’s assessment is that the available information, with no confirmed diagnosis, no causative agent and uncertainty about the source of exposure, “is not sufficient to draw a firm conclusion regarding the potential risk to the EU population.”
The caveats
Everything WHO and ECDC know about the clinical course comes from Russian authorities and from media reports that neither agency has verified. No pathogen has been identified, so the case cannot be classified as either a laboratory-acquired infection or an unrelated community pneumonia. WHO’s advice on strict biosafety practices in laboratories handling hazardous agents is, in its own words, precautionary and does not confirm a laboratory-acquired infection. Both agencies say their assessments will be reviewed if more information arrives.
This article is for general information and does not replace advice from a qualified clinician. Corrections: email the editor using the address on the Contact page.
