What is BF.7, the Omicron sub-variant driving the surge in China?

Source: The post is based on the article “What is BF.7, the Omicron sub-variant driving the surge in China?” published in Indian Express on 22nd December 2022

What is the News?

The current surge in Covid-19 infections in China is believed to be driven by the BF.7 sub-variant of Omicron that is circulating in that country. 

What is BF.7?

BF.7 is a sub-lineage of the Omicron variant BA.5.

It has the strongest infection ability since it is highly transmissible. It has a shorter incubation period and a higher capacity to cause reinfection or infect even those vaccinated.

But BF.7 is not the most resilient sub-variant of Covid-19 — a study has reported more than 10-fold higher neutralization resistance in another Omicron sub-variant called BQ.1.

A higher neutralization resistance means there is a higher likelihood of the variant spreading in a population and replacing other variants.

What are the symptoms of the BF.7 variant?

Persons infected with the BF.7 variant of Omicron may experience symptoms similar to other sub-variants. Common symptoms include fever, cough, sore throat, runny nose, vomiting, fatigue and diarrhea.

However, the variant is likely to cause severe illness among those with pre-existing medical conditions and weaker immune systems.

Have there been any BF.7 cases detected in India?

The first case of BF.7 in India was detected in October 2022 by Gujarat Biotechnology Research Centre. So far, two cases have been reported from Gujarat and one from Odisha.

Why is there a surge of Covid-19 cases in China?

China has been seeing a surge in cases ever since it relaxed the strict restrictions last month following rare public protests. 

China had been following a zero-Covid policy for the last three years, which involved extremely restrictive measures to deal with any surge in cases. Every known case, even asymptomatic, was mandatorily hospitalized, small outbreaks triggered hard lockdowns and suspected cases and all their contacts were kept under long isolation. 

The measures were painful but effective in keeping a check on the spread of the virus. However, it also meant that a large proportion of the population was never infected by the virus and had no natural immunity, thereby rendering it extremely susceptible So, once the virus was able to break through the defences, it spread rapidly in the population.

But isn’t a large chunk of China’s population vaccinated?

China indeed has a high vaccination rate — 235.5 doses per 100 population as per the WHO dashboard. However, China was among the earliest countries in the world to develop and administer vaccines to its population and its vaccines were developed against the original variant of the coronavirus.

The virus has mutated many times over since the beginning of 2020 — and the Omicron variants are known to evade the immune response from most vaccines currently in use.