Covid in China: What we know so far about the rapidly-spreading omicron subvariant BF.7

People line up to get tested for Covid-19 in China

China is witnessing a surge in Covid cases that has left offices and public spaces deserted, while hospitals are once again overwhelmed by long lines of patients. According to several news reports, it is the omicron subvariant BF.7 that is responsible for the Covid breakout in Beijing.

Since it emerged in 2021, the omicron variant of Covid-19 has evolved into multiple subvariants. Here is what we know so far about this rapidly-spreading subvariant BF.7:

BF.7 is short for BA.5.2.1.7, which is a sub-lineage of the omicron variant BA.5, according to Live Science. BF.7 reportedly has the strongest infection ability out of other omicron subvariants like BA.1 and BA.2

It also has a higher immune escape capability, Li Tongzeng, a medical expert at Beijing's Xiaotangshan Hospital, told Global Times. Immune escape is a phenomenon where the host’s immune system is unable to respond to an infectious agent.

Omicron BF.7 also has a shorter incubation period and faster transmission rate, which would explain why China is experiencing a sudden surge in cases.

"The basic reproduction number (R0) for Delta variant is around 5 to 6, that of Omicron BF.7 has exceeded 10," Li said. This means that a person infected with BF.7 can transmit the virus to an average of 10 to 18.6 other people.

The symptoms after being infected by the BF.7 subvariant are similar to other variants. Patients can experience cough, sore throat, fever, fatigue, runny nose, diarrhoea and more.

A number of infected people are asymptomatic, which further contributes to the spread of the virus.

Some health experts estimate 60% of people in China - equivalent to 10% of the world population - could be infected over the coming months, and that more than 2 million could die.

(With inputs from Reuters)