BA.4 and BA.5

These are the new sub-variants of Omicron which have emerged and been identified by the WHO. They have significant differences in their spike proteins from the earlier variants of Omicron which means that they can evade the antibodies provided in previous vaccines.  It was hoped that it would be possible to develop a vaccine aimed at aspects of the virus common to all the variants but that hope is fading. It seems that a new vaccine has to be developed for these variants.

These sub-variants are more contagious than their predecessors and are set to overtake them. There is no sign that they cause more serious disease although they are behaving a little bit like the pre-Omicron variants in liking proteins on the lung tissue.  It seems possible that they can cause reinfections of COVID-19 and that may have consequences in producing greater numbers of people with long COVID. It seems that getting COVID a number of times is a trigger for the long form of the disease.These two have rather difficult names but the fact is that the general public is not particularly interested in them.  Whereas each new variant used to be greeted with trepidation and fuss, the reaction now is extremely muted.

The naming system for subvariants follows the structure of a family tree. So AA to AZ is the first sublineage, BA to BZ the second, and so on. The number after the full stop indicates the next level down, the branchlet from the branch, so to speak. And the number after the next full stop takes you to the next level again. So BA.4 is the fourth sub lineage, BA.5 is the fifth. The WHO resists giving these subvariants names because it is arguably more useful to see all the Omicron variants grouped together. And I think they would run out of names. There is another variant from India which is attracting some attention and this is BA.2.75. Just to show that, whatever the WHO thinks, ordinary people would be happier with a more friendly name, this one was dubbed Centaurus by someone on Twitter and the name has stuck. There are quite a lot of names of stars and constellations that we could work with when we run out of the Greek alphabet.