although in south africa, for example, which has a lower vaccination rate than the u.s. there's also a lot of seropref lens. a lot of people had covid. coming off a huge delta wave. those combine for some sort of patchwork of immunity wall, right? >> exactly. for sure. >> dr. spencer, let me ask you, we talked to you throughout this pandemic. you've worked all over the world in very intense situations of viral outbreaks. you were a doctor during the ebola crisis. you were in new york during this first wave. i mean, what's your perspective on this data, what it means, first for new york but then let's zoom out to what it means for the hospital systems around the country. >> sure. well, it's great to be back. and good to see eric. look, we have an immunity wall here as well in new york city. right?