Dr. Deborah Birx: So we’re looking at all those studies very carefully. And I think you will remember over the last three weeks I’ve been talking about the level of asymptomatic spread and my concern about asymptomatic spread. Because, with flu and other diseases when people are sick, it’s easy to contact trace.
When people are not sick and shedding virus, you have to have a very different approach, a very different sentinel surveillance approach, a sentinel monitoring approach, which we outlined in the guidelines. And it’s why the guidelines took that very seriously. We knew that was unique for respiratory diseases, but it was because we were very concerned about the level of asymptomatic. And if you remember, we used to… We talked about younger age groups may have more asymptomatic disease and your asymptomatic disease may decrease with your older age groups, and that your symptomatic disease might increase with age groups. This is still our working hypothesis, we have no data right now still to support that.
But it’s these kinds of studies that help that. We know that New York and Detroit and other cities are very interested, which we want to also support them, in testing frontline responders, first responders and healthcare workers, because we think their exposure may have been the greatest. What we don’t want to do… And I’m just going to do another 30 seconds on testing. These tests are not 100% sensitive or specific. And I’m going to go over this over and over again. So if you have 1% of your population infected and you have a test that’s only 99% specific, that means that when you find a positive, 50% of the time will be a real positive and 50% of the time it won’t be.
And that’s why we’re really asking people to start testing in among the first responders and the healthcare workers that may have had the greatest exposure, because that’s where the test will be most reliable. And then, when we have the luxury, we can go out to broader and broader communities. But this has been the fundamental question to begin with, and has been persistent. And we will emphasize to the American people again, this is a highly contagious virus. And we don’t know by looking at someone whether they have preexisting conditions or not. And so, all of us as far as protecting others must continue to do all of the recommendations to ensure that when we are in an asymptomatic state, we’re not passing the virus to others.