WHO says no evidence of plague spreading after Siberian lab leak
World Health Organization Director‑General Tedros Adhanom Ghebreyesus said on 10 July 2026 the agency had seen no evidence that plague was spreading following a suspected laboratory leak in Siberia’s Irkutsk region.
The statement comes amid international concern that a lab‑worker’s death could signal a re‑emergence of a deadly bacterial disease, underscoring the importance of transparent reporting under the International Health Regulations.
Tedros noted that WHO’s assessment relies heavily on information supplied by Russian health authorities, which he said have been less forthcoming than the organization would prefer.
Russia’s Rospotrebnadzor reported that no new plague cases have been registered in Irkutsk oblast. An epidemiological investigation was carried out, preventive and control measures were implemented, and all identified contacts were placed under medical observation and tested. The agency said no high‑threat pathogens were detected among those contacts and that observation of all identified contacts has now been completed.
Roughly 200 people were initially monitored, with about 90 percent released after negative results. More than 4,900 laboratory tests were performed and found no additional infections.
The original patient, 28‑year‑old laboratory worker Daria Shipilova, died after developing severe pneumonia despite being vaccinated against the pathogens stored at the Irkutsk Anti‑Plague Institute, raising questions that WHO has asked Russian officials to clarify.
WHO has remained in contact with Russian officials, offering technical support and requesting further details on the cause of the severe pneumonia and reports of a second employee with undetermined pneumonia. The agency also offered lab‑capacity assistance and epidemiological expertise to help verify the pathogen involved. Tedros emphasized that timely, complete, and transparent information sharing is essential for accurate risk assessment.
He said the organization will continue to monitor the situation and will update the public as more information becomes available.