Is Original/BA4-5 booster coming or will Original/BA.1 be the only option for 4th dose ?

Reading from https://www.brusselstimes.com/282629/belgiums-new-vaccination-campaign-is-a-fourth-dose-really-necessary :

> “The updated vaccines contain the old strain of the virus that originated in Wuhan as well as the very first Omicrom BA.1 strain, meaning it will broaden people’s immune response,” he said. “It will have a greater variety of proteins and components in that vaccine, which is always a good thing.”

But BA5 is (at leat was in june) dominant in Belgium https://www.brusselstimes.com/243143/latest-omicron-sub-variant-now-dominant-in-belgium-what-does-this-mean

Europe greenlighted Comirnaty/BA4-5 bivalent vaccine https://www.ema.europa.eu/en/news/adapted-vaccine-targeting-ba4-ba5-omicron-variants-original-sars-cov-2-recommended-approval

Is there any chance to get the BA4/5 bivalent booster instead of the BA1 ? Or maybe BA4/5 will be available by January/February ?

Maybe it doesn’t matter much https://www.gov.uk/government/news/first-bivalent-covid-19-booster-vaccine-approved-by-uk-medicines-regulator (at least for Moderna):

> a booster with the bivalent Moderna vaccine triggers a strong immune response against both Omicron (BA.1) and the original 2020 strain. In an exploratory analysis the bivalent vaccine was also found to generate a good immune response against the Omicron sub-variants BA.4 and BA.5.

and https://www.nature.com/articles/d41586-022-02806-5:

> When the US booster campaign begins, it set to use different Omicron vaccines from the one approved by the United Kingdom. In June, an advisory committee to the US Food and Drug Administration (FDA) asked companies to develop bivalent vaccines that were based on the original strain and the BA.4 and BA.5 coronavirus variants — which have identical spike protein sequences — instead of the bivalent BA.1 vaccine that had been trialled by Moderna, Pfizer–BioNTech and others. The hope was that, by better matching circulating strains, the vaccines would prove more effective.

> But Cromer’s analysis suggests the differences might be paltry. Even updated vaccines based on the Beta and Delta variants should protect against BA.4 and BA.5 infections nearly as well as vaccines based on those variants. Similarly, bivalent vaccines that included the original vaccine looked no more effective than vaccines based solely on a newer variant.

> For these reasons, the FDA’s decision to spurn a BA.1-based booster probably wasn’t worth it, says Cromer, particularly as SARS-CoV-2 continues to evolve. “It doesn’t seem to suggest that it’s going to give a dramatic improvement in the effectiveness of the booster vaccine to have that slight change.”

Thanks for your input :).

edit: just read BA4/5 bivalent has been authorized in Belgium and will be used in the following weeks https://www.health.belgium.be/fr/news/cim-sante-publique-34 (sorry, I don’t have an english publication). It feels a bit like the whole “how do I avoid AZ and get an mRNA shot from last year) now.