BF.7 Variant of the Coronavirus

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 over there.

The dominant virus strain in China is BF.7, a sub-variant of Omicron that has been in circulation for over a year now.
There are over 500 Omicron sub-variants currently in circulation.
BF.7 is the name for the BA.5.2.1.7, which itself has evolved from the BA.5 sub-variant.
BF.7 is not unique to China.
- It accounted for over 5% of the cases in the US in October, 2022 and over 7% of the cases in the UK.
When viruses mutate, they create lineages and sub-lineages— like the main trunk of the SARS-CoV-2 tree sprouting branches and sub-branches.
A research study reported that the BF.7 sub-variant has a 4.4-fold higher neutralisation resistance than the original D614G variant— meaning 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 worldwide in 2020.
- A higher neutralisation resistance means there is a higher likelihood of the variant spreading in a population and replacing other variants.

When a virus multiplies, it doesn’t always manage to produce an exact copy of itself.
- This means that, over time, the virus may start to differ slightly in terms of its genetic sequence.

Any changes to the viral genetic sequence during this process is known as a Mutation.
Viruses with new mutations are sometimes called Variants. Variants can differ by one or multiple mutations.
When a new variant has different functional properties to the original virus and becomes established in a population, it is sometimes referred to as a New Strain of the virus.
- All strains are variants, but not all variants are strains.

Q. In the context of vaccines manufactured to prevent COVID-19 pandemic, consider the following statements: (2022)

The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.
Sputnik V vaccine is manufactured using vector-based platform.
COVAXIN is an inactivated pathogen-based vaccine.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Ans: (b)

Exp:

COVISHIELD vaccine is based on the platform which uses a recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 Spike (S) glycoprotein. Following administration, the genetic material of part of coronavirus is expressed which stimulates an immune response. Hence, statement 1 is not correct.
Sputnik V is the world's first registered vaccine based on a well-studied human adenovirus vector platform. It has been approved for use in 71 countries with a total population of 4 billion people. The vaccine is named after the first Soviet space satellite. The vaccine’s efficacy is 97.6%, based on the analysis of data on the incidence of coronavirus among Russians vaccinated with both vaccine components between December 5, 2020 and March 31, 2021. Hence, statement 2 is correct.
Covaxin is an inactivated viral vaccine. This vaccine is developed with Whole-Virion Inactivated Vero Cell-derived technology. They contain inactivated viruses, which cannot infect a person but still can teach the immune system to prepare a defence mechanism against the active virus. Hence, statement 3 is correct.
Hence, option (b) is correct.

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