What causes the spike in China for BF.7, the Omicron sub-variant?


The BF.7 sub-variant of Omicron that is prevalent in China is thought to be the cause of the present spike in Covid-19 infections there. This isn’t the first time BF.7 has been in the spotlight; back in October, it began to displace the main variations in the US and several other European nations.

About BF.7, what do we know?


As the main stem of the SARS-CoV-2 tree sprouts branches and sub-branches, so do viruses when they change, creating lineages and sub-lineages. The Omicron sub-lineage BA.5 and the BF.7 are identical. The latter is also known as BA.

The BF.7 sub-variant has a 4.4-fold higher neutralisation resistance than the original D614G variant, according to a study published in the journal “Cell Host and Microbe” earlier this month. This means that in a lab setting, antibodies from a vaccinated or infected individual were less likely to destroy BF.7 than the original Wuhan virus that spread throughout the world in 2020.

However, the study found that another Omicron sub-variant named BQ.1 had a more than 10-fold higher neutralisation resistance than BF.7, which is not the most resilient sub-variant.

A variant is more likely to propagate in a population and supplant other variants if it has a higher neutralisation resistance.

In October, BF.7 was the cause of more than 5% of cases in the US and 7.26% of cases in the UK. Scientists in the West were actively monitoring the mutation, but there was no noticeably higher number of cases or hospitalizations in these nations.

The BA.1 and BA.2 sub-variants of Omicron were responsible for the January 2022 wave in India. India experienced very few cases of BF.7 since the subsequent sub-variants BA.4 and BA.5 were never as common there as they were in European nations (which is an offshoot of BA.5).

Data from India’s national SARS-CoV-2 genome sequencing network show that just 2.5% of cases in November were caused by BA.5 lineages. Recombinant variation XBB, which accounted for 65.6% of all cases in November, is currently the most prevalent variant in India.

So what was unique about China?

According to experts, an immunological-naive population rather than the BF.7 variant’s increased transmissibility or immune evasiveness was to blame for the rise in cases in China.

India today issued a fresh Covid advisory after alarming reprts from China prompted a high-level meeting to chalk out the strategy to prevent a surge here. India’s COVID-19 tally today climbed to 4,46,76,330 with 131 fresh infections, while the number of active cases came down to 3,408, according to Union health ministry data.

India also reported the first cases of Omicron subvariant BF.7, apparently the strain driving China’s current surge of Covid cases.

The first case of BF.7 in India was detected in October by Gujarat Biotechnology Research Centre.

Health Secretary Chandigarh Yashpal Garg on Wednesday said that the administration would increase testing to 600 per day in view of the guidelines from the Centre regarding COVID-19 cases.

“Central government has already instructed to keep track of COVID cases and related trends. We will increase testing from 100 to 600 per day. We are taking precautions, I appeal to people to get vaccinated soon,” Yashpal Garg, Health Secretary told ANI.

“If required we will increase the tests. There are chances of an increase in cases when the testing is increased. There is no need to worry as of now. We are taking precautions. We will also send samples for genome sequencing to keep track of the variants,” he said.

“We also have stocks of medicines, oxygen and beds. I appeal to people who have not taken the booster dose or if not taken their first and second doses they should get vaccinated soon. We have a vaccination camp going on in sector 16,” the Health Secretary added.

Delhi government is keeping a watch on the COVID-19 situation and Chief Minister Arvind Kejriwal has directed the health department to ensure genome sequencing of samples and take other steps needed to meet any eventuality, officials said on Wednesday.

Amid a sudden spurt in COVID-19 cases in Japan, South Korea, Brazil, China, and the US, the central government had on Tuesday urged all states and Union territories to gear up the whole genome sequencing of positive samples to keep track of emerging variants.

What causes the spike in China for BF.7, the Omicron sub-variant?

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