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.5.2.1.7.
The BF.7 sub-variant has a 4.4-fold higher neutralization 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 neutralization 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 neutralization 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.
In China, what was different?
According to experts, the rise in cases in China was not caused by the BF.7 variant’s increased transmissibility or immunological evasiveness, but rather by an immune-naive population.
China is currently going through the regular Omicron spike that other nations have already seen, precisely as the one Hong Kong had when it loosened its limitations, according to Dr. Anurag Agarwal, the former leader of India’s Covid-19 genome sequencing consortium INSACOG.
“Because the population had already been infected and immunized, it appeared to us that the Omicron wave was milder. Furthermore, during the Delta wave, we have “paid the price” (of April-May 2021). People died, but those who did had stronger immune systems. Apart from that, Omicron has primarily killed elderly people, and we (India) do have a younger population, according to Dr. Agarwal.
Because most people recover after a bout of fever, coughing, and sore throat, even highly transmissible variations haven’t resulted in a flood of cases.
Only those nations, including Australia, New Zealand, and Singapore, who remained entirely closed until they could immunize their entire population and then opened up, did not pay much of this “premium,” according to Dr. Agarwal.
According to Dr. Agarwal, only those countries that remained completely closed until they had immunized their entire population and then opened up, such as Australia, New Zealand, and Singapore, did not pay a significant portion of this “premium.”
“We have occasionally seen increases in cases in numerous nations as Omicron continues to mutate to avoid the immunological pressures.”
But isn’t most of China’s population vaccinated?
According to the WHO dashboard, China has a high immunization rate of 235.5 doses per 100 people. However, China was one of the first nations in the world to create and provide its citizens with immunizations, and those vaccines were created to protect against the original coronavirus type.
Since the start of 2020, the virus has undergone numerous mutations, and the Omicron versions are known to subvert the immunological response induced by the majority of currently available vaccinations.
(In fact, a significant proportion of individuals who had had two vaccinations contracted the Omicron wave in India.) To offer improved protection, various companies have developed bivalent vaccinations.
“Vaccines could stop the illness from spreading up until Omicron. The vaccines don’t stop transmission after Omicron, but they do stop mortality, according to Dr. Agarwal.
Additionally, he emphasized that mRNA vaccines, such as those created by Pfizer and Moderna, have proven to be more effective than “dead virus” vaccines, such as those used in China. “Whether some vaccines are superior to others is a subject of discussion. Furthermore, Hong Kong provides unequivocal proof that recipients of the mRNA vaccines fared better than recipients of the dead viral vaccine, according to Dr. Agarwal.
Is there a chance that the epidemic will recur globally in a bad wave?
Although it cannot be fully ruled out, Dr. Ekta Gupta, professor of virology at the Institute of Liver and Biliary Sciences, affiliated with INSACOG, believes it is improbable that a new variation will emerge as a result of the high transmission in China.
“The spike protein mutations have slowed considerably; there hasn’t been a significant alteration in about a year. This explains why just sub-lineages have appeared in place of new variants. You can see that the distance between the spike protein and Delta, or even between Delta and Omicron, in the original D614G variant was significantly greater than what we are currently observing, the researcher added.
Dr. Gupta, however, advised against abandoning all safety measures. “SARS-CoV-2 is now present in humans and will remain so. In the winter, when all respiratory infections often increase, there could be an increase in the number of Covid-19 cases.
