Thread by @vipintukur

In a new study, the researchers develop a panel of mRNA-LNP-based vaccines using the RBD of #Omicron & #Delta, which are dominant in the current wave of COVID-19. 1/

In addition to the Omicron- & Delta-specific vaccines, the panel also includes a “#Hybrid” vaccine that uses the RBD containing all 16 point-mutations shown in Omicron & Delta RBD, as well as a #bivalent vaccine composed of both Omicron and Delta RBD-LNP in half dose. 2/

Interestingly, both Omicron-specific & Hybrid RBD-LNP elicited extremely high titer of NAbs against Omicron itself, but few to none NAbs against other SARS-CoV-2 variants. 3/

The bivalent RBD-LNP, on the other hand, generated antibody with broadly neutralizing activity against the WT-virus & all variants.

Surprisingly, similar cross-protection was also shown by the Delta-specific RBD-LNP. 4/

Key takeaways:

1-Omicron-specific mRNA vaccine can induce potent NAb response against Omicron

2-A vaccine based on original WT strain is a poor inducer of NAbs against Omicron. 5/

3-An Omicron-specific vaccine is a terrible inducer of NAbs directed against non-Omicron variants
4-Inclusion of epitopes from other variants may be required for eliciting cross-protection. 6/

biorxiv.org/content/10.110…