Moderna checks a few boxes in phase 3 mRNA flu shot trial, but misses on B strains and safety

Moderna had high hopes for its first seasonal flu vaccine to enter the clinic, but, so far, the mRNA shot hasn't quite lived up to the hype. While the vaccine checked off two influenza A strains in a phase 3 trial, it struggled against two B strains in the same test and had a higher level of adverse events than an approved flu shot.