CDC’s Redfield explains the change in guidance for shorter quarantine after COVID-19 exposure

Speaking to an online forum with the U.S. Chamber of Commerce, CDC Director Dr. Robert Redfield explains the agency’s change in guidance on quarantining after exposure to the coronavirus. The CDC now says quarantining may end at seven days after testing negative, or at 10 days without a test.

Video Transcript

ROBERT REDFIELD: So quarantine is-- you know, and isolation is a key tool, as I mentioned, to try to keep this virus from spreading. And a lot of people never understood when, if I was infected, I was told to isolate for 10 days. But if I was not infected, I was told to isolate for 14 days. And a lot of people suggested that maybe I didn't make any sense because why do I isolate for only 10 days if I am infected and then I isolate for 14 days if I'm not?

And the reason for that is if I know I'm infected, either I got tested and I was asymptomatic or if I got symptomatic and got tested, we know that the virus shedding within the body in an individual that's infected really does become next negligible at 10 days, and that's why we were able to have people test out of quarantine when they were infected at 10 days.

But the problem with people who were exposed, we don't know if you're exposed, when does your body start to replicate the virus? And originally we had studies that said the average was 5.2 days, and then later we had studies that said it was seven point, I think, something-- somewhere in the seven days. And so we only had data to really look at when was the probability that I was not going to somehow start shedding the virus? And it turned out that the greatest probability that we would not miss anybody was 14 days, and that's why we have it.

Now, we've since done a number of studies because obviously 14 days quarantine has an impact on productivity. 14 days quarantine also has an impact on whether people quarantine. And we've done a lot of studies over the spring and summer, and then we were able to get enough data then that we could model. And you are right. Today, actually, the new guidance will be coming out from CDC. I think they're doing a press thing as we speak.

And that guidance is, again, based on data that we gathered and modeling of that data that if you isolate for 10 days that the probability that you will start replicating the virus after that is about 1%. So it's a balance. It's not that 14 days is bad. It's just that how does society want to balance it? Do you want to get 99.9%, or if we're 99%, is that good enough at 10 days?

And that model also shows that if you test-- and we've done this with the SEC football leagues in trying to gather all this data and some other college groups. If we test at day five, six, or seven and you're negative, it's about-- the model would predict that we-- we'll define at least 95%.

The CDC now is coming out with guidance today to allow people to make those judgments that they can test out at seven days, and they can get out of 10 days. But at the same time if they want to be perfect-- you know, closest to perfect, they can stay in isolation for 14. So that will be coming out today.

I think that's going to make a big impact. We found a lot of people really don't isolate for 14 days. You know, and I think getting people to commit to this getting out of the transmission cycle I think is important. So that's the data that will be coming out today. Seven days with a test between day five and day seven and 10 days without a test.