
Pfizer has begun a study comparing its original COVID-19 vaccine with doses specially tweaked to match the hugely contagious omicron variant.
Pfizer and its partner BioNTech announced the study on Tuesday.

Pfizer has begun a study comparing its original COVID-19 vaccine with doses specially tweaked to match the hugely contagious omicron variant.
Pfizer and its partner BioNTech announced the study on Tuesday.