Vidcast:  https://youtu.be/874VfupQy_I

 

Pfizer has developed two Omicron-targeting boosters: one is their Omicron BA.1 adapted vaccine and the other is their Omicron BA.4/BA.5 adapted vaccine.  The former has been tested in humans while the latter has only been tested in mice and human studies are expected to begin soon.

 

Pfizer has applied to the FDA and the European Medicines Agency for EUAs for both versions.  The BA.1 version contains mRNAs that encode for the antigens associated with both the original CoVid version and the Omicron BA.1 subvariant. The BA.4/BA.5 version contains the same mRNAs that encode for the antigens associated with both the original CoVid version but also mRNAs the encode for  Omicron BA.4 and BA.5 subvariant antigens.

 

Pfizer has human data only for the BA.1 version and that shows a 9.1 fold rise in protective antibodies against BA.1.  There is no human data regarding this booster’s protective antibodies against BA.4/BA.5.  The mouse data shows shows a good protective antibody boost.

 

The FDA has today approved the BA.4/BA.5 adapted version without human test data.  Scientists there have accepted Pfizer’s argument that this booster is fundamentally similar to their original vaccine and BA.1 booster in efficacy and safety.  We’ll see tomorrow what the CDC decides before release to the general public.

 

https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-omicron-adapted-covid-19

 

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