The researcher from the National Institute of Health Dr. Ricardo Jorge (INSA) explained that his opinion is in line with that of the scientific community in general.

Speaking to journalists, the microbiologist explained that, from the beginning, it was realised, looking at the 'cocktail' of mutations, that “it is difficult to understand how BA.2 can be considered a sister of BA.1, because they have many differences”.

“I would say that the only great similarity it that it has is a very high number of mutations when compared to all other variants”, said the coordinator of the study on the genetic diversity of SARS-CoV-2 in Portugal.

"In the Spike protein, the two strains have a dozen mutations that are shared, which is why the WHO said that it is all Omicron, defining several strains (BA.1, BA.2 and BA3), but a more detailed analysis shows that they have many mutations that are not shared. BA.1 has 11 mutations that are not shared with BA.2 and BA.2 has seven or eight that are not shared with BA.1. All in all, they have more differences than similarities”, said João Paulo Gomes.

On Tuesday, WHO considered that, based on available data on transmission, severity, reinfection, diagnosis, therapy and vaccine impact, BA.2 should continue to be considered a variant of concern and should remain classified as Omicron.

Dominant strain

The INSA researcher also said that epidemiological data unequivocally show that the BA.2 lineage is replacing BA.1 because it is more transmissible, and it is estimated that within two weeks it will “completely dominate”.

In Portugal, João Paulo Gomes said, "BA.2 will have surpassed 50% of cases this week and if the growth rate remains at 3%, 4% per day it will be a matter of weeks until it reaches 80, 90 %".

“We are following the path that other countries have followed”, he said, noting that South Africa and Denmark reached almost 100% in a few weeks”.

“Portugal, United Kingdom, Norway, Sweden, Switzerland and Germany are following the same path and we all have BA.2 prevalences between 30% and 50%”.

João Paulo Gomes also highlighted data from a “very robust” study carried out by Japanese researchers, whose data are still under peer review, in mice and cell models that were used to characterise Delta and BA.1.

“The results obtained were reflected in human reality, that is, it was found that they could be translated into clinical infection in humans”, he explained, adding that these results “are not very encouraging because they show that in addition to BA.2 being more transmissible, showed greater pathology in infected mice and that antibodies generated by infection with BA.1 were not effective in preventing infection with BA.2".

This situation, according to the researcher, raises a question in relation to the monovalent vaccine that is being developed by some pharmaceutical companies against BA.1 in order to understand to what extent it can be effective, taking into account that these studies indicate that it will not be.

In this perspective, the scientific community considers that it would be prudent to consider BA.2 not as a lineage of Omicron, but as a variant of concern, possibly with a Greek letter associated with it, he concluded.