Experts recently added a new term: the “Omicron-2” variant of the coronavirus. Officially referred to as B.1.1.529, it has 3 main sub-variants: BA.1, BA.2. and VA.3.
According to the World Health Organization, more than 99% of the cases identified as of December involved the BA.1 strain, which we have so far commonly referred to as Omicron. However, recently the BA.2 sub-variant, which is precisely Omicron-2, has begun to actively manifest itself.
Theodora Psaltopoulou (Professor of Internal Medicine-Epidemiology-Preventive Medicine), Lina Pashu (Associate Professor of Endocrinology) and Gikas Majorkinatos, Associate Professor and Rector of EKPA, report that at the molecular level, the Omicron-2 or BA.2 subvariant represents some common and many different mutations compared to BA.1.
Differences between Omicron and Omicron-2
In fact, the differences between BA.1 and BA.2 are much larger than between the original Omicron covid variant and the Alpha mutation. This has raised concerns in the scientific community, as the identified molecular differences could lead to different properties in terms of detection, rate of spread, severity of the disease, and effectiveness of vaccine protection.
Omicron-2 is detected by standard diagnostic tests, like Omicron. However, it was called “invisible” because it does not have the mutation indicator that BA.1 has to distinguish it from the Delta variant. This leads to the fact that a number of diagnoses attributed to Delta are actually Omicron-2.
Data from the Nordic countries, where detailed genomic analysis is performed, suggest that Omicron-2 is more contagious than BA.1.
In Denmark, it accounted for 20% of all cases in the last week of 2021, compared to 45% in the second week of 2022. In Norway, Omicron-2 was detected in 7 cases by 4 January. In just 15 days, the number of laboratory-confirmed cases of BA.2 reached 611. Other countries, such as the UK and Sweden, are seeing an increase in its cases.
In Greece, too, the first cases of the Omicron 2 mutation have recently been identified, in travelers from abroad who have been traced.
On a positive note, Omicron-2 does not appear to have other characteristics of more dangerous “behavior”. In Denmark, for example, no differences were found in the number of hospitalizations for BA.2 compared with BA.1.
The results of studies on the efficacy of vaccines against this subvariant are awaited with interest. There is optimism that vaccinations will continue to protect against serious illness and death from COVID-19 after exposure to Omicron-2.
The World Health Organization (WHO) is tracking a new variety of omicron strain BA.2 not separately, but in combination with other subspecies, according to a representative of the organization.
According to WHO, as of January 7, the main subtype of omicron BA.1 accounts for about 98% of the genetic sequences uploaded to the international GISAID database. The organization said that in the BA.2 variety, unlike BA.1 and BA.3, one of the mutations characteristic of the strain is missing – a deletion, that is, the loss of amino acids 69-70 in the S-protein gene.
It was previously reported that it is this difference of BA.2 from the “standard” versions of the strain that makes it kind of “invisible” for PCR tests. Instead of a positive result, testing systems may fail.
Infection with this variety of omicron strain was found in three people in Sweden. The Academic Laboratory in the Swedish city of Uppsala is not sure whether the new subspecies of the strain will be able to compete with the previous version of omicron. The new mutation has also been found in South Africa, Australia, the UK, Israel, Denmark, Norway and India.