Social media speculation about a possible disease outbreak in Russia has reportedly prompted some Chinese residents to stock up on essential goods, reviving fears of COVID-era restrictions despite no confirmed evidence that plague has spread into China.

Residents were reportedly buying rice, sugar, eggs, canned food and other necessities amid online claims that an outbreak could prompt lockdowns similar to those imposed during the COVID-19 pandemic. The reports have centered on speculation circulating online rather than confirmed infections in China.

The concerns followed the Oct. 2 death of a 28-year-old employee at a Russian institute in Irkutsk that studies plague. Russian authorities reportedly placed at least 200 people under monitoring or quarantine-related measures following the incident. Moscow has denied that the woman died from plague, stating that pneumonia was responsible.

However, the response has drawn scrutiny from public health experts. Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, said Sunday that the precautions surrounding the death raised questions about what Russian officials may have suspected.

“What worried me was the response of the Russians, the 200 people that were being monitored, the quarantining of a hospital, the hazmat suits,” Adalja said during an appearance on Newsmax. “That type of reaction made me think this was something worse than plague.”

Adalja noted that plague is generally treatable with antibiotics when diagnosed and treated promptly, and that it does not typically spread rapidly from person to person. He argued that the scale of the reported response appeared unusual for a routine plague case.

The expert also pointed to the Soviet Union’s historical biological weapons program, which included plague research. Adalja said he believes that program may have resumed, though that assertion has not been independently established by the information available about the current incident.

The World Health Organization said in a report Saturday that Russia had reported negative test results for plague and other high-threat diseases, with no additional linked cases identified. However, the cause of the woman’s death remained undetermined.

Adalja acknowledged that the Russian government’s denial could be accurate, but said key questions remain unanswered, including what investigators were testing for and which diseases they initially suspected.

“But we still don't know what killed her, what they were testing for, what they were suspicious of,” he said. “And I don't know if we'll ever get good answers.”

For now, claims of a plague outbreak spreading into China remain unconfirmed. The reported panic buying highlights how uncertainty surrounding a disease investigation can fuel public anxiety, particularly in a country whose population experienced sweeping restrictions during the COVID-19 pandemic.