Timeline of the suspected Irkutsk plague case
Every development in the suspected plague case in Irkutsk, Russia, newest first. Each entry gives the date, names its source and carries a label for how well it is sourced.
October 2026
- Confirmed
WHO report: cause still unknown, no travel restrictions advised
WHO published a Disease Outbreak News report on the event, titled "Pneumonia of undetermined etiology." It said it had found no evidence of ongoing transmission and does not advise any restrictions on travel or trade, but that it had not received information identifying the cause of death and that a laboratory-associated exposure "cannot be fully excluded at this stage."
Source: WHO
- Confirmed
Russia tells WHO tests found no plague
According to WHO's report, Russian authorities said the worker and all identified contacts were 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 said two independent investigations found no laboratory biosafety incidents and that no further cases of severe pneumonia were linked to this one.
Source: WHO
- Confirmed
Medical observation of contacts ends
Russian authorities told WHO that, as of 9 October, none of the dangerous pathogens the laboratory works with had been found in any contact, and that their medical observation had ended. Contacts had been watched for seven days, in healthcare facilities or at home, with daily laboratory tests, and none developed symptoms, WHO said in its 10 October report.
Source: WHO
- Confirmed
ECDC: not enough information to judge the risk to the EU
ECDC said in its weekly threats report 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.
Source: ECDC
- Reported
Russian watchdog says measures complete, 5,500 tests negative
Rospotrebnadzor said its measures in the Irkutsk region were complete, that more than 5,500 laboratory tests had found no dangerous pathogens and that two biosafety commissions had found no accidents at the institute, Interfax reported. It described the illness as community-acquired pneumonia.
Source: Interfax (in Russian)
- Reported
Russian watchdog calls second-case reports incorrect
Rospotrebnadzor said reports of a second case linked to the laboratory worker were "incorrect," CNN reported, citing the Russian news agency TASS. No health authority has confirmed a second case.
Source: CNN
- Reported
Quarantine in the Irkutsk region reported lifted
Russian state media reported that quarantine measures in the Irkutsk region had been lifted, according to the Kyiv Independent. The Irkutsk regional governor said in a Telegram address that nearly 5,000 laboratory tests had found no dangerous pathogens, the Kyiv Independent reported.
Source: Kyiv Independent
- Confirmed
WHO says it cannot yet do a full risk assessment
WHO's Director-General said WHO did not yet have the full picture and was "not able to conduct a full risk assessment." WHO asked Russia for details of the laboratory tests, the reasons for the measures and the contacts' health, and offered technical support.
Source: WHO
- Confirmed
Russian watchdog reports nearly 5,000 negative tests
Rospotrebnadzor said medical monitoring was complete for over 90% of contacts, nearly 5,000 laboratory tests had found no dangerous pathogens and there was no epidemic risk to the region, as quoted by CNN and Euronews. CNN also reported that it was winding down its preventive measures.
- Unconfirmed
- Reported
EU health officials meet, take no decisions
The European Commission convened the EU's Health Security Committee with ECDC and WHO, but the meeting ended without specific decisions because of a lack of reliable information from Russia, Euronews reported.
Source: Euronews
- Confirmed
Russia tells WHO there is no recent plague case
Russia replied to WHO that no plague case had recently been reported in the Irkutsk region and that about 200 contacts were in quarantine, WHO's Director-General said on 7 October. This confirms what Russia told WHO, not the cause of death.
- Reported
WHO gives an initial risk estimate, to be updated
A WHO spokesperson said all of the patient's contacts had reportedly been identified and none had shown symptoms so far, UN News reported. WHO's initial risk assessment, which it said would be updated, put the risk as moderate to low in Irkutsk, low for Russia and very low for the WHO European Region. On 7 October WHO experts said the risk was now undetermined, CNN reported; WHO's 10 October report gave no risk levels.
- Confirmed
ECDC: no reports of onward spread so far
The European Centre for Disease Prevention and Control said that, based on the limited information available, no secondary cases had been reported and there was no evidence of sustained human-to-human transmission.
Source: ECDC
- Reported
Central Asian countries step up border health checks
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.
Source: The Times of Central Asia
- Reported
Russian watchdog says no laboratory accident found
Rospotrebnadzor said tests on samples from the worker found no microorganisms linked to their work and no accidents had been detected at the institute, Euronews reported. The Irkutsk regional governor said an expert commission had found the cause of death to be pneumonia of unknown cause.
Source: Euronews
- Reported
First official statement: pneumonia of unknown cause
Rospotrebnadzor's first public statement described the death as "pneumonia of unknown etiology" and did not use the word plague, The Moscow Times reported, citing the newspaper Vedomosti.
Source: The Moscow Times
- Confirmed
WHO asks Russia for information
WHO asked Russia for information about the reported case under the International Health Regulations, the rules countries follow when sharing information on health threats, WHO's Director-General said on 7 October.
Source: WHO
- Reported
Suspected plague case reported in Irkutsk
Media reported a suspected case of pneumonic plague in a laboratory worker at the Irkutsk Antiplague Research Institute, who died after being hospitalized with severe pneumonia, WHO later said. The Irkutsk regional governor said contacts were under medical observation with no signs of illness, The Moscow Times reported.
Source: WHO, The Moscow Times
For the whole story so far, with every claim sorted by how reliable its source is: What happened →
Questions about the timeline
- 01
Has plague been confirmed in Irkutsk?
No. As of 11 October 2026, no health authority has published a confirmed diagnosis. Russian authorities told WHO that tests on the worker and contacts found no plague and that the death was pneumonia of undetermined etiology. WHO said on 10 October that it had not received information identifying the cause.
- 02
What do the labels on each update mean?
Confirmed means we can link to the health authority's own statement, such as a WHO or ECDC page, or at least two independent, bylined news outlets reported it from their own sources rather than copying each other. Reported means only one outlet relayed a health authority's statement, the source was an unnamed official or an official who is not from a health authority, or officials described the detail as preliminary. Unconfirmed means it circulated but we could not verify it. The label describes the source, not how likely the claim is.
- 03
How often is this timeline checked?
We check WHO, ECDC and news reports of Russian health authority statements regularly while the story is developing, and add an entry when something new is said on the record. The date at the top of the page shows the last check.
- 04
Where does WHO publish official updates?
WHO posts statements and briefing remarks in its newsroom and publishes formal outbreak reports on its Disease Outbreak News page; its first report on this event came out on 10 October 2026. In Europe, ECDC covers health threats in its weekly Communicable Disease Threats Report.