can keep this up. it is exhausting. but there is still no clear booster time line for adults under 65 vaccinated with pfizer or for the 45% of americans inoculated with moderna or johnson & johnson. >> today's decision only addresses some americans. but in other countries where they are offering boosters, they are mixing and matching vaccines why aren't we doing this in the u.s. >> yeah. this is something where we really wanted to let data lead because we want to make the most safe recommendations for americans. >> reporter: the staggered roll-out of boosters will happen at pharmacies, health care clinics and doctors' offices. many are still anxious about when it will be their turn. >> one family said that they're living like hermits now waiting for the booster. so there is a lot of anxiety. >> reporter: tonight for many americans an added shot of protection while millions more are left with another dose of frustration and confusion. >> and, miguel, as you know, there is a lot to sort through here there are some people between 18 and 49 who do qualify