Yesterday the UKHSA (UK Health Protection Agency) published some data for the first time on British infections due to BA.2 sub-variant of Omicron. The data is interesting, as it adds to some of what we know so far, thanks to information from Denmark, a country where most of the new cases of infection are from the Omicron ba2 isolate.

So let’s first recap what we knew about Ba.2. Already in the first Omicron samples obtained in Africa, three different types of Omicron variants were found, namely Ba.1, Ba.2 and Ba.3. These differ from each other for a good number of mutations; Differences in the spike protein, in particular, are relevant to distinguish Ba.1 from Ba.2, as the former has a small missing trait (a deletion) in the spike protein, the latter does not exhibit this characteristic. From the point of view of detection, this makes an important distinction: molecular tests using PCR are, in fact, able to uncover the lack of the Ba.1 spike protein fragment, allowing it to be understood with good reliability. whether a subject is infected. From Omicron ba.1 without necessarily having to resort to sequencing, which is longer and more expensive. In countries such as Denmark or Great Britain, where so far only the omicron exists, it is therefore sufficient to look at PCR to determine whether a subject is infected with BA1 or BA2, thanks to the small deletion that differentiates does the spike of the first sub-version from the second; And this fact is important for monitoring the development of one or the other in real time.

Now, it can be seen that, even in the presence of the very wide spread of Omicron Ba.1, the arrival of Ba.2 dominated this second edition in Denmark (today it is over 65 percent) in that nation. cases); And also in other countries, where Omicron Ba.1 has now become the dominant form, it is observed that all other variants have almost disappeared, except for the sub-variant Ba.2, which is rapidly gaining ground.

As recently announced by Danish health authorities, Omicron Ba.2 is estimated to be 1.5 times more transmissible than Ba.1; However, at the moment, there is no difference in terms of pathogenicity. In addition, the first sporadic cases of reinfection by Omicron Ba.2 in Denmark were observed a few weeks earlier in subjects infected with Ba.1; However, at this time these data do not allow to draw conclusions, as they may be special cases, which may occur in subjects who have not developed sufficient immunity for various reasons.

We then come to the latest figures, which, as mentioned, are coming from Great Britain. As of 16 January, Omicron Ba.1 accounted for over 96 percent of cases in the UK; Ba.2 amounted to 3.4 percent. However, using the various signals given by PCR as an estimate, it can be seen that between January 17 and January 24, Ba.2 could have gone up from 2.2 per cent to 4.4, similar to that seen in Denmark and As can be seen in this also. Germany. In households, Ba.2 Omicron appears to be more prevalent than Ba.1, increasing the risk of infection by 10 to 13.4 percent in people living with such an infected person; However, these are preliminary data, which do not yet take into account variables such as vaccination status, and therefore reflect only an acceleration in prevalence, which is still considered confounding factors to provide an accurate assessment of increased transmittance. needs to be cleaned.

Finally, a very important fact: at the moment, still relatively small numbers of pure, English data do not show a difference in the efficacy of vaccines between Ba.1 and Ba.2. This data is consistent with unpublished studies from the university.

The Oxford Institutions cited in the UKHSA report show that the neutralization efficiency of the sera of vaccinated individuals is similar against that of the two Omicron sub-versions. This last element, combined with the absence of the risk of hospitalization and the serious consequences Denmark reported earlier, should reassure us. The virus is evolving, further increasing its transmittance and again denying those who speak and speak about the pathogen’s peak fitness; However, our clinical defenses are still in place, and given that Ba.2 is spreading and no other forms have yet been observed, the fact that Moderna, after Pfizer, also launched its new vaccine against Omicron. The moment the test version is announced, it seems. Improve our prospects further.