that rapid test will be given to everyone, including nursing home staff and workers in pre schools. michael mina is a professor at harvard school of public health. he has been begging this drum for a month. he wrote, a goal of rapid testing is to keep nine out of ten infectious people from walking into a train station and infecting others. this is an engineering problem, not medicine. he joins me now. michael mina, let's start on the accuracy of these tests, because i think back last year they got a bad rap. people generally felt like, oh, they are not reliable, they get false positives. my understanding is that they have gotten better and they are now being used quite well. what is your general feeling about their accuracy? >> it's a terrific question.