How dangerous is the Covid-19 variant circulating in China?

After a meeting with Chinese scientists, the World Health Organization (WHO) technical advisory group on virus evolution confirmed that Covid-19 cases in China were caused by Omicron sub-variants BF.7 and BA.5.2.

According to the Indian Express, the claim is based on an analysis of two data sources: 2,000 genomes sequenced since December 1, 2022, and 773 genomes on the global GISAID database. These two variants account for more than 95% of the sequenced genomes.

The Omicron sub-variant BA.5.2 was detected in some samples as early as June 2020. It was not until July 2022 that BA.5.2 and BA.5 began to spread and become dominant in some countries. However, BA.5.2 is less likely to cause serious consequences.

The new variants tend to have milder symptoms but are still dangerous for the elderly and those with underlying medical conditions. Illustration: Livescience

BF.7 has been around for a long time

The above variant, fully named BA.5.2.1.7, is a sub-branch of BA.5 belonging to Omicron. This is one of more than 500 sub-variants of Omicron in circulation.

BF.7 is not a new variant that emerged in China. According to the WHO, there are currently no new variants or mutations of concern emerging from China. BF.7 was reported in other countries before the surge in cases in China. BF.7 accounted for more than 5% of cases in the US and 7% of cases in the UK in October.

Scientists are paying attention to BF.7 because it is better at evading the immune response from vaccination or past infection. However, countries (outside of China) have not seen a significant increase in cases and hospitalizations due to BF.7.

Meanwhile, according to The Conversation, in December 2022, BF.7 was identified as the main variant spreading in Beijing and contributing to the increase in the number of Covid-19 infections in China.

Experts believe the surge in China is due to the majority of the population not having immunity to the sub-variants of Omicron.

Symptoms and infectiousness of BF.7

BF.7 has the R346T mutation also present in BF.7's "parent" BA.5 variant, which is associated with the virus's ability to overcome the body's immunity despite vaccination or previous infection.

Reports from China note that BF.7 is the most infectious of the Omicron sub-variants in that country, with a shorter incubation period. An infected person will transmit the virus to 10 to 18 other people, while an average person with Omicron infects five people.

The high transmission rate of BF.7, coupled with the potential risk of many asymptomatic carriers, is causing significant difficulties in controlling the epidemic in China.

Symptoms of BF.7 infection are similar to other Omicron subtypes, primarily involving the upper respiratory tract. Patients may experience fever, cough, sore throat, runny nose, and fatigue. A small number of people experience gastrointestinal symptoms such as vomiting and diarrhea. BF.7 can cause more severe illness in people with weakened immune systems.

As Omicron evolves, we see the emergence of new sub-variants that are better able to evade immunity, including BF.7.

According to Vietnamnet