The World Health Organization says Russia has not shared enough information to fully assess the death of a laboratory worker in Siberia that raised fears of pneumonic plague.

Darya Shipilova, 28, worked at the Irkutsk Anti-Plague Research Institute and died on October 2 of pneumonia of unknown origin. About 200 people who may have been exposed were quarantined as a precaution.

Russian health regulator Rospotrebnadzor said nearly 5,000 laboratory tests found no dangerous pathogens among contacts, and most quarantined people have been released. Moscow says there is no epidemic risk and has denied reports of a confirmed second case.

WHO Director-General Tedros Adhanom Ghebreyesus said on October 7: ‘We don’t yet have the full picture of this event and we’re not able to conduct a full risk assessment.’ The agency says Russia reported no confirmed plague cases in Irkutsk.

The WHO assesses the risk as low for Russia and very low for Europe. It is seeking clarification on the cause of Shipilova’s illness and reports of a possible second patient.