The Omicron variant was first detected in November 2021
There is also a BA.3 subvariant of Omicron, the World Health Organisation (WHO) said on Saturday.
Though the third wave of COVID is waning, the degree of risk stays the same as it was before. On March 5, 2022, Maria Van Kerkhove, Infectious Disease Epidemiologist and COVID-19 Technical Lead at the World Health Organisation (WHO), said that there is a similarity in terms of severity between BA.2 and BA.1 subvariants of Omicron and added that among all lineages of Omicron there is also BA.3 lineage.
While on one hand, this statement gives a ray of hope that BA.2 sub variant of Omicron which was thought to be severe is mild as the BA.1 subvariant is, but on the other hand with the report of another subvariant it also gives out a message that nothing is over yet and the coronavirus is still a dangerous virus lurking all around us.
The Omicron variant was first detected in November and on November 26, the WHO designated it as a variant of concern. "The most prominent ones that have been detected worldwide are BA.1, BA.1.1 and BA.2. There's also a BA.3 and other sub lineages," said Maria Van Kerkhove.
What is BA.3 Omicron subvariant?
Omicron includes Pango lineage B.1.1.529 and descendent Pango lineages BA.1, BA.1.1, BA.2 and BA.3, as per WHO information.
A research study published on January 18, 2022 in the Journal of Medical Virology has also confirmed the presence of BA.3 sub lineage.
"Our study found that there were no specific mutations for the BA.3 lineage in spike protein. Instead, it is a combination of mutations in BA.1 and BA.2 spike proteins," the study says. The study adds that BA.3 sub lineage was first detected in north west South Africa. As per the study as on January 11, 2022 of the total genome sequences submitted to the GISAID database only 0.013% were of BA.3 Omicron subvariant and the highest were of BA.1. The study further found that there were fewer mutations in BA.3 than BA.1 and has speculated that loss of mutations might be a reason why BA.3 has less number of infections.
BA.3 has been called as the less-prevalent lineage of Omicron by many research studies.
Why is BA.3 a less-prevalent Omicron subvariant?
"...it can be speculated that the reason for the BA.3 lineage spreading at very low speeds and causing fewer cases may have been due to the loss of six mutations (ins214EPE, S371L, G496S, T547K, N856K, and L981F) from BA.1 or obtaining two mutations from BA.2 (S371F and D405N)," says the January 2022 research study.
So far the dominant subvariants of Omicron have been BA.1 and BA.2 and both of them have no difference in the severity they cause.
What are the severities and symptoms linked with Omicron?
The severity that a variant of the virus has on the human body depends on how the host body reacts to the virus.
Omicron is considered to be the milder variant of coronavirus among all other variants which have been detected so far. During the third wave which was primarily caused by its subvariant BA.1, there were less cases of hospitalization. However, this variant has a rapid rate of transmission.
In December 2021, a month after the subvariant was detected, experts had said that Omicron is contagious but is less likely to put one in hospital. “Unlike the pattern observed in the Beta and Delta waves, the rise in cases during the Omicron wave was not accompanied by a concomitant rise in hospital admissions,” a December 2021 research study published in the Lancet had said.
To understand the severity of the Omicron variant, the WHO is looking at experimental data on whether this variant causes severe disease in hamsters. Speaking about a Japanese study, Maria Van Kerkhove said, “And this is an experimental study, looking at hamsters in particular. And what they were looking at is whether or not, experimentally within hamsters, there was a signal of causing more severe disease under these experimental conditions. We are also looking at severity in what we call the real world," and added that in countries where both BA.1 and BA.2 were in circulation there has been no change in terms of hospitalization.
While nothing much has yet been said about the severities caused by the three sub variants, except that they have similar severities which is obvious as they share the same parental variant, a January 2022 report on Forbes has said," We reiterate that BA.1, BA.2, and BA.3 differ from each other as much as the Alpha, Beta, Gamma, and Delta variants differ from one another. Several mutations differ between the three as well. We suspect that these differences will be reflected in the septic characteristics of each variant affecting growth rate, suppression of innate immunity, virulence, and vaccine evasion."
The common symptoms of Omicron COVID infection are: sore throat, runny nose, sneezing, headache, body ache and mild fever.