Suspected plague in Irkutsk: what happened

In a Disease Outbreak News report on 10 October, WHO said the worker was hospitalized with severe pneumonia on 29 September and died on 2 October. Russian authorities told WHO that the worker and all identified contacts had been tested for a broad range of pathogens, including plague, with negative results for high-threat pathogens, and that the death was classed as pneumonia of undetermined etiology. They also said the worker had been vaccinated against the dangerous pathogens they worked with and had not travelled outside the Irkutsk region in the two weeks before falling ill.

Russian authorities told WHO that contacts were watched for seven days, in healthcare facilities or at home, with daily laboratory tests, that all stayed free of symptoms, and that observation had ended by 9 October. They said more than 5,500 laboratory tests found no dangerous pathogens, two independent investigations found no biosafety or biosecurity incidents at the institute, and no further cases of severe pneumonia were linked to this one, according to WHO's report.

WHO said it had not identified evidence of ongoing transmission and does not advise any restrictions on travel or trade. It also said it had not received information identifying the cause of the fatal illness, could not independently judge whether contacts were monitored for long enough, and that a laboratory-associated exposure "cannot be fully excluded at this stage."

WHO's Director-General said on 7 October that media first reported a suspected case of pneumonic plague in a laboratory worker at the Irkutsk Antiplague Research Institute on 2 October, and that the worker died after being hospitalized with severe pneumonia. WHO asked Russia for information under the International Health Regulations on 3 October.

Russia replied to WHO on 6 October that no plague case had recently been reported in the Irkutsk region and that about 200 contacts were in quarantine, according to WHO's Director-General. This confirms what Russia told WHO, not the cause of death.

WHO said it had asked Russia for details of the laboratory tests, the reasons for the measures taken and the health of the contacts, and had offered technical support. Without the full picture, the Director-General said, WHO is "not able to conduct a full risk assessment."

Russia's public health watchdog, Rospotrebnadzor, said on 7 October that medical monitoring had been completed for over 90% of contacts, that nearly 5,000 laboratory tests had found no dangerous pathogens, and that there was no epidemic risk to the region, as quoted by CNN and Euronews.

A WHO spokesperson said on 6 October that the cause of death had not been officially confirmed and that all of the patient's contacts had reportedly been identified, with none showing symptoms so far, UN News reported.

The European Centre for Disease Prevention and Control (ECDC) said on 6 October that, based on the limited information available, no secondary cases had been reported and that there was no evidence of sustained human-to-human transmission. It noted that plague can be treated with antibiotics.

ECDC said in its weekly threats report on 9 October that the information available was not sufficient to draw a firm conclusion about the potential risk to the EU population. It said WHO had asked Russia for the cause of the severe pneumonia, the pathogen that triggered the public health measures, and about media reports of a second employee with pneumonia.

WHO's initial risk assessment, which a WHO spokesperson said on 6 October would be updated, put the risk as moderate to low in Irkutsk, low for Russia and very low for the WHO European Region, UN News reported. On 7 October WHO experts said the risk was now undetermined, CNN reported; WHO's 10 October report gave no risk levels.

Rospotrebnadzor described the illness as community-acquired pneumonia on 8 October, Interfax reported. In its report to WHO, which WHO published on 10 October, Russia used the term pneumonia of undetermined etiology.

Russian state media reported on 8 October that quarantine measures in the Irkutsk region had been lifted, according to the Kyiv Independent. Rospotrebnadzor had said a day earlier that it was winding down its preventive measures, CNN reported.

The Kremlin spokesperson said most media reporting on the case was "false information," according to Euronews and Al Jazeera.

The US State Department said it had officially requested more information from the Russian government, CNN reported.

The European Commission convened the EU's Health Security Committee with ECDC and WHO on 7 October. The meeting ended without specific decisions because of a lack of reliable information from Russia, Euronews reported.

Kazakhstan's health ministry said on 5 October that it had ordered closer checks at border crossings. Kyrgyzstan and Tajikistan also ordered closer health checks for people entering the country, and Uzbekistan strengthened the readiness of its health services, The Times of Central Asia reported on 6 October.

Rospotrebnadzor said tests on samples from the worker found no microorganisms linked to their work and that no accidents involving pathogens had been detected at the institute, Euronews reported. Among the contacts, it said, two COVID-19 and two rhinovirus infections were found and no other infections.

Rospotrebnadzor's first public statement, on 4 October, described the death as "pneumonia of unknown etiology" and did not use the word plague, The Moscow Times reported, citing the Russian newspaper Vedomosti.

Early media reports suggested the worker was infected through an accidental exposure in the laboratory. No health authority has confirmed this. Russian authorities told WHO that two independent investigations found no biosafety or biosecurity incidents; WHO said on 10 October that, with the cause still unknown, a laboratory-associated exposure "cannot be fully excluded at this stage."

Media reports said a second employee had pneumonia of undetermined cause. WHO said on 7 October that it was seeking to verify these reports. Rospotrebnadzor called reports of a second case "incorrect" on 8 October, CNN reported, citing the Russian news agency TASS, and Russian authorities told WHO that no further cases of severe pneumonia were linked to this one, WHO said on 10 October.