CDC Director Rochelle Walensky appeared on "Good Morning America" on Wednesday morning to discuss several important updates about the Covid-19 pandemic. First, she discussed concerns that the Omicron variant may evade the at-home testing kits that are currently available. "We still are encouraging their use," Walensky said about the tests <a href="https://www.realclearpolitics.com/video/2021/12/21/watch_live_president_biden_speaks_about_covid-19.html">the Biden administration just ordered 500 million of</a>. "They may not work as well as they have for the [other variants]." Next, she addressed updated guidelines reducing the isolation period for asymptomatic people who test positive for the virus from 10 days down to 5. ABC's host asked: <i>"Former Surgeon General Jerome Adams said this is not about the best science, it is kind of a compromise to keep the economy open."</i> "We had a lot of science to inform our decisions, science in many different areas," Walensky replied. "We do know that the vast majority of viral transmissions happen in those first five days -- somewhere in the 85-90% range. So if you can isolate for those first five days, that would be great." "We also know epidemiologically that we anticipate a lot of cases. We've seen in other countries that up to 4 or 5% of people may have an infection. So we really do need to prepare for what happens, especially if those people are asymptomatic or mildly symptomatic, and they are really ready to go out and about." She added: "We've seen in some studies that up to only a third of people actually isolate when we ask them to." "So with all of that science together, we moved forward with an isolation period of five days of isolation followed by five days in a mask," she added. Third, she discussed new information about how long people will show a positive result on a PCR test versus for how long they are actually contagious. "We know that PCRs can stay positive for up to 12 weeks, so we would have people in isolation for a very long time if we were relying on PCR testing." ABC's host asked this question: <i>"Did the decision have anything to do with the government's ability to actually meet the demand for testing?"</i> "In our isolation recommendations, we did not recommend a test because we did not know what we would do with the information and it would not inform any further decision-making," Walensky explained. "But in our quarantine recommendations, our recommendations for what to do if you are exposed to the virus, we recommend and clearly say the best practice would be to get a test five days after exposure." "Our recommendations are true for both adults and for children," Walensky added. She also discussed the same questions on CNN: <blockquote class="twitter-tweet"><p lang="en" dir="ltr">“It really had a lot to do with what we thought people would be able to tolerate,” CDC Director Walensky says on why the CDC shortened the isolation period from 10 days to 5 days if you’re asymptomatic. Our full interview: <a href="https://t.co/rO7blPFiPj">pic.twitter.com/rO7blPFiPj</a></p>— Kaitlan Collins (@kaitlancollins) <a href="https://twitter.com/kaitlancollins/status/1476176642250842114?ref_src=twsrc%5Etfw">December 29, 2021</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script> <blockquote class="twitter-tweet"><p lang="en" dir="ltr">I can't even express how angry this makes me. Think of all the lives ruined, jobs lost, education squandered b/c of false positives. We've been saying since summer 2020 that the PCR test can be positive at 5 days or 75 days. And ONLY JUST NOW is it being used to adjust policy. <a href="https://t.co/4Q6rHFDB4S">https://t.co/4Q6rHFDB4S</a></p>— Justin Hart (@justin_hart) <a href="https://twitter.com/justin_hart/status/1476226243238395907?ref_src=twsrc%5Etfw">December 29, 2021</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>