Mere days after rivals Pfizer (NYSE:PFE) and BioNTech (NSDQ:BNTX) announced the launch of a study testing an omicron-based booster vaccine candidate, Moderna (NSDQ:MRNA) has announced its own trial of an omicron-specific vaccine. The vaccine booster candidate, mRNA-1273.529, will be the subject of a Phase 2 study involving approximately 600 participants divided into two cohorts. The…