https://apnews.com/cd39872e31c490cb92c7678a8de83499

COVID-19 vaccines tweaked to better match today’s omicron threat are expected to roll out in a few weeks but still up in the air is how much benefit the booster shots will offer, who should get one -- and how soon.

Pfizer and rival Moderna both asked U.S. regulators this week to authorize modified versions of their booster vaccine — shots that are half the original recipe and half protection against BA.4 and BA.5, the newest versions of omicron.