
Pfizer has begun a study comparing its original Covid-19 vaccine with doses specially tweaked to match the Omicron variant
(Picture: AP)Pfizer Inc and BioNTech have announced the start a clinical trial to test a new version of their vaccine specifically designed to target the Omicron variant of Covid-19 Omicron variant.
The highly transmissible strain has eluded some of the protection provided by the original two-dose vaccine regimen.