isolate for five days, but there was not any guidance to get a test. tonight, what they're now saying about tests, saying you can get one after five days, but that if you get it and it's negative, you should still take precautions. so, dr. jha is here, what does this all mean tonight? and what kind of test is best to determine whether you're still contagious? and of course, all of this comes as the u.s. now averages nearly half a million new cases a day. the cdc estimating 95% of them are now omicron. the lines for testing are growing even longer. tonight, president biden announcing he will double the purchase of pfizer's new covid pill, that anti-viral pill, the first of its kind, now 20 million doses purchased, though most won't be available until after this current surge. it comes as hospitalizations among children now soaring, record numbers. at texas children's hospital, for one, the numbers quadrupling there in a month. so, as i mentioned, dr. jha is standing by here, but first, our chief national correspondent matt gutman. >> reporter: tonight, the cdc under growing scrutiny for