let's discuss all of this with bloomberg managing editor for global business, emma o'brien. a taking the unusual step of endorsing vaccine mixing for boosters. what are they saying? emma: you have the u.s. drug authority approving the moderna vaccine, booster for americans aged 65 and over, along with those over 18 at higher risk. they said any adult who received the johnson & johnson one-shot vaccine can get a booster two months after receiving their first dose which is pretty aggressive. alongside that, as you noted, they said that any of the three covid vaccines authorized in the u.s., moderna, pfizer, biontech shot, and johnson & johnson, could be given as a booster. this shows the u.s. is really doubling down the booster program, given the uptick in cases and deaths we have seen in the past month or so. most of those have been in unvaccinated people with the u.s. hitting a bit of a hesitancy wall since its initial rollout but there has been breakthrough cases and this is what this is targeting, especially in people who got their vaccinations early. haidi: in the meantime