#NewsBytesExplainer: What is BF.7, Omicron sub-variant triggering China's COVID-19 spurt
What's the story
Four cases of Omicron sub-variant BF.7, which is believed to be driving the current spurt of COVID-19 cases in China, were reported in India on Wednesday.
It first made headlines in October, when it replaced the dominant variants in the US and Europe.
BF.7, which branched out of BA.5, has the strongest infection ability since it is highly transmissible.
Context
Why does this story matter?
BF.7's neutralization resistance is reportedly 4.4 times more than D614G—the original variant which spread worldwide from Wuhan in 2020.
In October, BF.7 accounted for over 5% of cases in the US and 7.26% in the UK, though there wasn't any drastic change in the number of hospitalizations.
In November, BA.5 lineages accounted for 2.5% of cases in India.
Lineages
China's rise in cases due to immunologically naive population: Report
BF.7 is short for BA.5.2.1.7, a sub-lineage of Omicron's BA.5 sub-variant.
BA.4 and BA.5 never took hold in India and the January 2022 wave was driven by BA.1 and BA.2 sub-variants.
The reason for its spread in China is not its neutralization resistance or higher transmissibility but the immunologically naive population, as per the Indian Express.
Reason
India paid the price during Delta wave: INSACOG ex-chief
Indian SARS-CoV-2 Genomics Consortium's (INSACOG) former head, Dr. Anurag Agarwal, said that China was witnessing the "typical Omicron surge" that other countries also faced.
He said the Omicron wave looked milder in India as the population was already infected and vaccinated.
India "paid the price" during the Delta wave in April-May 2021, and those who survived came out with improved immunity, he added.
Statement
Hong Kong faced similar surge after relaxing norms
Agarwal said Omicron was largely affecting the elderly and India has a younger population.
Hong Kong experienced a similar increase in cases after easing restrictions.
Notably, China's rise in cases has followed the relaxing of norms under its zero-COVID-19 policy.
He said the countries that remained closed until complete vaccination, such as Australia, New Zealand, and Singapore, didn't suffer as much.
China
China developed vaccines before later mutations
Though China has a vaccination rate of around 90% or 235.5 doses per 100 persons, as per the World Health Organization (WHO), it developed and administered the vaccines to people against the original variant D614G.
Since then, the virus mutated many times over, and the Omicron variants are known to dodge the immune responses from current vaccines.
Quote
mRNA vaccine better than 'killed virus' vaccine
The current vaccines aren't very efficient at neutralizing the Omicron variants but they prevent deaths. Agarwal said that mRNA vaccines, such as those developed by Pfizer and Moderna, are more effective than the 'killed virus' vaccine, as evident from Hong Kong.