The staff of Guangzhou Baiyunshan Pharmaceutical General Factory sort out the packed ibuprofen tablets on Demcember 29, 2022. Photo: VCG

Montmorillonite powder, an antidiarrheal drug, sold out in China and topped Weibo's trending search list on the morning of New Year's Day, after it was widely circulated on social media platforms that the contagious Omicron subvariant XBB causes gastrointestinal symptoms such as nausea, vomiting, and diarrhea.

Currently, several online pharmacies and e-commerce platforms have run out of Montmorillonite powder, while norfloxacin, Zhengchangsheng, or live bacillus licheniformis capsules, probiotics products and electrolyte drinks have also seen hot sales.

The mass buying came after a screenshot was spread on social media platforms, which said that "XBB1.5 strain has topped other variants in the US, and people should stock up on montmorillonite powder and norfloxacin," according to an online snapshot seen by the Global Times over the weekend.

Some netizens expressed fears of XBB spreading after China announced on December 27 that it will scrap nucleic acid tests for international arrivals to the country from January 8, and those with normal health declarations will no longer undergo any special procedures.

The XBB1.5 variant has become the dominant strain in the US in the last week of 2022, accounting for 40.5 percent of all COVID infections, according to the US Center for Disease Control and Prevention.

The subvariant has already landed in China, with Hong Kong reporting its first infection from the XBB strain in October, though a Shanghai-based expert said on Monday that the Omicron BQ.1 and XBB strains found so far in Shanghai have only been detected in a very small number of international arrivals, who were quarantined, and have not caused local transmission in society.

"It is not necessary to stock antidiarrheal drugs such as montmorillonite powder, since the entry situation of Omicron strains remains unclear. Antibiotics such as norfloxacin have no effect on viral diarrhea and may increase the risk of antibiotic-associated diarrhea, allergies and drug resistance," an industry insider, who works for a supplier of pharmaceutical excipients, told the Global Times on Monday on the condition of anonymity.

It is more important to prevent dehydration and disturbance of water and electrolyte balance during diarrhea, the insider noted.

However, the insider also said that the lack of montmorillonite powder is temporary and its supply will quickly resume just like the supply of fever, cough and other drugs.

At present, the supply of antipyretic drugs, Lianhua Qingwen, N95 masks, antigen self-testing kits, thermometers, oxygen generators, and relevant drugs has been fully restored on e-commerce platforms Taobao and Tmall, according to a statement sent from Tmall to the Global Times on Monday.

According to Tmall, the daily supply of antigen test kits has more than doubled, and the 48-hour delivery rate of antiviral medicines has risen to 80 percent, and is expected to return to normal levels next week.

The minimum price of N95 masks has been restored to 2 yuan ($0.29) per piece, and the minimum price of a single antigen self-testing kit has been reduced to less than 5 yuan on online platforms.

Yang Yongsen, a business manager at Lepu Medical Technology (Beijing) Co, said that at present, the production capacity of the company's antigen self-testing products is 10 million per day, which is expected to continue to grow in the coming weeks. The company, together with Tmall, will guarantee the online supply of antigen products. 

In response to the short-term surge in demand for drugs, Tmall said that it has cooperated with dozens of pharmaceutical brands such as Guangzhou Baiyunshan Pharmaceutical Holdings Co., Andon Health Co., Cofoe Medical Technology Co. and other companies to increase production and expand capacity to ensure the production and supply of key anti-COVID products.

"From the perspective of the whole country, the peak of COVID-19 infections is expected to be from mid-January to early February, so fever drugs are still in need," said the insider.