A health officer in Istanbul, Turkey, wears protective clothing before collecting swab samples from ... [+] confined people who may be infected with the Covid-19 coronavirus and thus may be infected. (Photo by OZAN KOSE/AFP via Getty Images)

You may be able to lose a guy in 10 days, based on the 2003 rom-com movie How to Lose a Guy in 10 Days. That also may be time that it takes for you to lose enough of the Covid-19 coronavirus so that you are no longer contagious, based on updated guidance from the Centers for Disease Control and Prevention (CDC).

The CDC is now saying that if you have mild-to-moderate Covid-19, keep yourself isolated from other people for at least 10 days after you first noticed symptoms. You can discontinue this isolation after the 10-day mark if you havent had a fever for at least 24 hours and your other symptoms have improved. Note that not having a fever because you took a fever-reducing medication like Tylenol doesnt count. That would be cheating. The fever has to have naturally disappeared. Still having a fever after 10 days means that you may need not only more cowbell but also more isolation.

This is a bit different from what the CDC was saying back in April, which was about three missed haircuts ago. As I wrote for Forbes at the time, the threshold back then was seven days rather than 10 days for discontinuing isolation. Also, the previous threshold for being fever-free was 72 hours instead of 24 hours. So in the words of Guns N Roses, youll need a have little more patience. Wait three days longer before exposing yourself to others. Actually, that came out wrong. Wait three days longer before interacting in any way with others.

Isolation much more than social distancing. Social distancing should be maintained even after ending ... [+] isolation. (Photo by Alexi Rosenfeld/Getty Images)

Keep in mind that isolation is not the same as social distancing. You should still social distance after ending isolation. As Ive indicated previously, social distancing means staying at least one Ryan Gosling away from everyone else. As actor Gosling is approximately six feet tall, this would be keeping at least one lying Gosling apart. A Gosling lying on the floor, that is.

Isolation, instead, entails staying in a room or rooms by yourself away from others. That means no Ryan Goslings, no Ryan Reynolds, no Ryan Chappelles, no Dave Chappelles, no David Crosses, no Marcia Crosses, no Marcia Bradys. Nobody else should be there. No one should enter that room unless they have are wearing a full set of personal protective equipment, known affectionately as PPE. It also involves not sharing any items that you may have contaminated with others, including that mountain of toilet paper that you have amassed around your bed.

Isolation is different from quarantine as well. The U.S. Department of Health and Human Services (HHS) website includes the following easy-to-remember phrases:

As you can see, its all about the might. Isolate yourself when you already know that you are infected. By contrast, quarantine yourself when you think that you may have been exposed to the virus. Another way to remember when to quarantine is the q. Quarantine when theres a question whether you are infected. Isolate when you say I am infected. Quarantine does not become isolation until you have either had a positive test for the RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or developed symptoms that suggest Covid-19.

New York Gov. Andrew Cuomo Governor Andrew M. Cuomo has announced that individuals who have traveled ... [+] to New York from higher-risk states should quarantine for 14 days. (Photo by Jeenah Moon/Getty Images)

The recommended quarantine duration is still at least 14 days because thats how long the incubation period may potentially last. The incubation period is the time from when you are exposed to when you first develop symptoms and may last anywhere from two to 14 days, based on studies so far. So if you think you got exposed to the Covid-19 coronavirus during that ill-advised Real Housewives of Beverly Hills in-person watch party, youll have to view the show for the next two weeks by yourself, far away from anyone else, except for perhaps that massive pile of toilet paper next top your bed.

If you have more severe Covid-19 or a weak immune system then you could remain contagious for longer than 10 days. More severe cases may shed more virus for longer periods of time. The CDC is now recommending that those with severe-to-critical illness or a very weak immune system stay isolated for at least 20 days after the onset of symptoms. Of course, if you have severe-to-critical Covid-19, you really should be in the hospital. So this guidance is more for health care workers taking care of patients with Covid-19.

What if you tested positive for the SARS-CoV2 but never developed any symptoms? Well, the threshold is still 10 days. But for asymptomatic infections, staying isolated for 10 days after symptom onset would mean that you would stay isolated forever, which would be a really long time.

Instead, the guidance is to stay isolated for 10 days from the date of your first positive test for SARS-CoV-2 RNA. In this case, RNA stands for ribonucleicacid rather than rations not available or really not avocado. RNA is the viruss genetic material. A SARS-CoV-2 RNA test is when someone sticks that cotton swab way up your nose or to the back of your throat or both to get samples to test for the presence of the virus genetic material. This is probably an experience that you would remember. It is not the blood test that checks for antibodies to the SARS-CoV2.

Covid-19 coornavirus RNA testing typically involves sticking a cotton swab up your nose, although ... [+] alternatives such as spit testing are emerging. (Photo by Mario Tama/Getty Images)

Speaking of testing, heres another change in the CDC guidance. The CDC used to recommend that health care workers with Covid-19 stay isolated until they have a negative test for SARS-CoV2 RNA. However, studies have been showing that you can still have a positive test but no evidence of replication-competent virus in your upper respiratory tract. Replicate means reproduce, just in case you havent seen the word replicate used on someones dating profile. Therefore, a replication-competent virus means a virus that is able to reproduce and thus infect someone.

Finding virus RNA is not necessarily the same as finding whole live versions of the virus. In fact, virus RNA can still be found in specimens from your upper respiratory tract for as long as three months after you first noticed symptoms. This can be a bit like finding someones bling without finding that person himself or herself. Its still not clear what finding such RNA means without detecting replication competent virus, whether it represents fragments of the virus, weakened versions of the virus, inactivated virus, hide-and-go-seek virus, or something else.

These updated guidelines are based on studies showing that the chances of finding replication-competent virus in respiratory tract specimens steadily goes down with passing time after symptom onset. In other words, your infectiousness may go down each day that you have symptoms. In these studies, researchers were not able to find replication-competent virus in patients with mild-to-moderate Covid-19 after 10 days had elapsed since their symptoms first manifested.

In a study thats posted on MedRxiv and hasnt yet undergone peer-review, researchers were able to find replication-competent viruses between 10 and 20 days after symptom onset in patients with severe Covid-19. However, 10 and 15 days after symptom onset, already about 88% and 95% of the specimens, respectively, in this study no longer had replication-competent virus. Of course, take any study thats just on MedRxiv with a grain or even a toilet paper roll package of salt until its been published in a reputable peer-reviewed scientific journal.

So 10 and 20 are now the numbers to remember when it comes to contagiousness and isolation. These thresholds are based on studies to date, so they could change as more evidence emerges. The Covid-19 coronavirus is like that person that you just met on Tinder. It still is rather mysterious, may not be completely what it seems, and could make you very sick.

Also, consider these numbers to be rough estimates rather than exact deadlines. Dont set your timer so that you can start panting on other people right after the 10- or 20-day mark has passed. It cant hurt to stay cautious for a little extra time. After all, viruses, like some guys, could end up hanging around a little longer than expected.

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How Long Are You Contagious With Covid-19 Coronavirus? Heres A CDC Update - Forbes