BA.2 subtype has already spread to northern European countries, but it is unclear whether it is more contagious or causes more serious disease.
Greece was added to the list of countries where the coronavirus BA.2 variant has been detected on Friday, which has already spread widely in Denmark and other European countries, but it is not yet known if it behaves differently from the original Omicron strain.
According to information, two cases were confirmed last week at the “Eleftherios Venizelos” airport. It seems to be the first in Greece, as on Thursday Professor Gikas Majorkinis had stated that until then no incidents had been recorded in the country.
The sub-variant BA.2, which was unofficially christened “Omicron 2”, is one of the three branches into which Omicron has been divided, and presents significant differences from the original strain (BA.1) in the mutations it carries.
It was discovered in early December and is already being detected in at least 43 countries, according to data compiled by the Scripps Institute in California.
Despite the lack of sufficient genetic data, BA.2 seems to already prevail in the Philippines and India, especially in the Calcutta region where it accounts for 80% of cases, the Times of India reported a few days ago.
BA.2 also spreads to Britain, Norway, Sweden and Denmark, accounting for most of the 8,000 cases recorded to date worldwide.
According to the Danish State Serological Institute, BA.2 accounted for 20% of Covid-19 cases in mid-December, up from 45% in the second week of January.
The first data are reassuring
BA.2 carries several different mutations and may behave differently from the original Omicron in terms of transmissibility, severity of the disease, and escape from the immunity offered by the vaccine or natural infection.
However, a preliminary analysis by the Danish institute “shows no differences in hospitalizations in BA.2 compared to BA.1”.
Existing vaccines are expected to protect against serious disease as with the original Omicron, the institute added.
The same view was expressed on Thursday by Dr. Majorkinis: “It does not seem that there are significant differences between one branch and the other in terms of, say, morbidity or contagion. “It’s still early,” he said.
Attempts are now being made to culture the virus in the laboratory to see if it can be effectively neutralized by antibodies isolated from the blood of vaccinated individuals and former patients.
Genetically, BA.2 differs from the original Omicron more than Omicron differs from the Alpha variant of the coronavirus.
The monitoring of BA.2 may be more difficult, as this sub-variant is not easily distinguished from other variants in the PCR examination.
The reason is that BA.1 lacks a mutation (S-gene target failure) that allowed the diagnosis of the original Omicron.
This is why BA.2 is also called the “stealth” variant, a term that normally refers to airplanes that remain invisible on radar.
“We named it stealth because it has a mutation at position 67 that makes it undetectable by the classical method we use,” said Dr. Majorkinis.
However, this difference does not affect coronavirus patients, as the vast majority of positive samples do not undergo genetic analysis to determine which strain is responsible for the infection.