tonight, several developing stories as we come on the air. now the second vaccine breakthrough. one week after the news from pfizer, moderna today announcing its new vaccine is nearly 95% effective. the company hoping to have 20 million doses ready by the end of this year. in addition to 20 million by the end of the year expected from pfizer. tonight, one of the key differences between the two vaccines. and when will most americans get access to either one of them? it doesn't come a moment too soon. tonight, cities and states imposing new restrictions. some with stay at home advisories. 1 million new cases in the u.s. in less than a week. california's governor saying he's pulling the emergency brake. new restrictions in several states and in the major cities, from philadelphia to chicago, where the mayor there is asking