Five things you should know about Omicron subvariant XBB

Writer: Zhang Yu  |  Editor: Zhang Chanwen  |  From: Shenzhen Daily  |  Updated: 2023-01-05

The new Omicron subvariant XBB has raised concerns about another potential wave of COVID-19 cases recently. At present, the prevalent viral strains in China are BA.5.2 and BF.7, but strains such as BQ.1 and XBB have been getting more prevalent in other countries.

Are these strains being locally transmitted? Will they trigger a new round of infections? Here are the five things you should know about the subvariant XBB.

Q: What is XBB?

A: According to Xu Wenbo, head of the viral disease institute of the China Center for Disease Control and Prevention, BQ.1 and XBB are Omicron subvariants and have become prevalent in some European and North American countries. The subvariants have an enhanced ability to spread and evade immunity.

Q: Is XBB more infectious?

A: According to Xu, BQ.1 and XBB have no obvious difference in pathogenicity compared with other Omicron subvariants. The incidence rate of severe cases and mortality rate of BQ.1 and XBB have not increased in countries where the strains are prevalent.

In the past three months, China has detected the imports of BF.7, BQ.1 and XBB. But BQ.1 and XBB have not become prevalent in the country. The predominant strains are still BA.5.2 and BF.7.

Q: Is XBB being locally transmitted?

A: According to Yuan Zheng’an, an expert from Shanghai’s epidemic prevention and control leading group, BQ.1 and XBB found in Shanghai were only detected in very few inbound travelers and have not caused locally transmitted cases on a community level.

Q: Can an individual who has recovered from COVID still get infected with XBB?

A: Li Tongzeng, a respiratory and infectious disease specialist at Beijing Youan Hospital, Capital Medical University, said that XBB has an enhanced ability to evade immunity, but is different from the country’s prevalent BA.5 strain.

After a person is infected with BA.5 for a period of time, he or she will face increased risk of reinfection when encountering a viral strain that has a stronger ability to escape immunity. But reinfection primarily occurs in people with weak immunity.

People with normal immunity are relatively unlikely to get infected again in a short time and will experience milder symptoms compared with the first infection.

Q: Will XBB cause diarrhea?

A: Li said some COVID patients have symptoms such as vomiting and diarrhea, which will generally go away in one to three days. So far, it hasn’t been found that XBB is more likely to attack the cardiovascular and digestive systems.