major carrier to mandate employee vaccinations could it do the same for passengers and why now is the time to shop for a new credit card. >> announcer: this is "nbc nightly news" with lester holt >> hello, everyone great to be back from our coverage at the olympics, but returning, frankly, to a country that sadly looks a lot more like last winter when it comes to covid that's how much ground we've lost in the fight against the pandemic as we're about to show you, in some parts of the country, hospitals themselves are on the critical list. available icu beds counted in single digits, or worse yet, patients turned away. as the danger of the delta variant becomes more apparent each day, more americans are getting vaccinated that number well above 166 million. finally edging above the 50% mark but the goalposts may be moving. the threshold for herd immunity now calculated to be well beyond 80%, according to a recent briefing by the infectious