Study shows COVID-19 patients testing positive after recovery aren’t infectious

In a very positive sign for U.S. states, countries, and regions reopening economies around the world, researchers have found evidence that patients who test positive for COVID-19 disease caused by the SARS-CoV-2 virus after recovering aren’t infectious and could have the antibodies that prevent them from falling sick again.

Research last month showed that PCR tests for the coronavirus’ nucleic acid can’t distinguish between dead and viable virus particles, potentially giving the wrong impression that someone who tests positive for the virus remains infectious.

COVID-19 infectious. Image: Closeup of COVID-19 coronavirusHeesu Lee and Jason Gale for Bloomberg News:

Scientists from the Korean Centers for Disease Control and Prevention studied 285 COVID-19 survivors who had tested positive for the coronavirus after their illness had apparently resolved, as indicated by a previous negative test result. The so-called re-positive patients weren’t found to have spread any lingering infection, and virus samples collected from them couldn’t be grown in culture, indicating the patients were shedding non-infectious or dead virus particles.

The findings, reported late Monday, are a positive sign for regions looking to open up as more patients recover from the pandemic that has sickened at least 4.8 million people. The emerging evidence from South Korea suggests those who have recovered from COVID-19 present no risk of spreading the coronavirus when physical distancing measures are relaxed.

The results mean health authorities in South Korea will no longer consider people infectious after recovering from the illness… authorities said that under revised protocols, people should no longer be required to test negative for the virus before returning to work or school after they have recovered from their illness and completed their period of isolation.

Experts believe antibodies probably convey some level of protection against the virus, but they don’t have any solid proof yet. Nor do they know how long any immunity may last. A recent study in Singapore showed that recovered patients from severe acute respiratory syndrome, or SARS, are found to have “significant levels of neutralizing antibodies” nine to 17 years after initial infection, according to researchers including Danielle E. Anderson of Duke-NUS Medical School.

MacDailyNews Take: The finding that those who’ve recovered from COVID-19 disease caused by the SARS-CoV-2 virus aren’t infectious is a huge positive as we proceed toward herd immunity ahead of an effective vaccine!


  1. Making lemons out of lemonade, MDN. The discovery that PCR tests cannot identify persons who are currently infectious is not positive at all. The whole strategy for safely coming out of quarantine depended entirely on large-scale testing, contact tracing, and isolation. If we cannot do that, reopening becomes a crap shoot for players who are blindfolded.

    As for “herd immunity,” that requires from 60-80% of the people in a local community to have antibodies from either infection or vaccine. Currently, antibody tests in even the most heavily affected areas like Lombardy and NYC are coming in at under 25%. If that has required over 90,000 deaths, what will it take to reach herd immunity?

      1. Lombardy has 10 million inhabitants. The antibody tests suggest that about 21% have been infected = 2,100,000. There have been 32,000 deaths = 1.52%.

        The US has 330 million inhabitants. To reach the absolute minimum for herd immunity nationwide (60%, though it could be 80%) = 198 million. Assuming the same case fatality rate as Lombardy (1.52%), as the worst possible case, that would mean 3 million dead.

        If you want to take your chances on that, I wish us all luck.

        1. Lombardy has the oldest average age of any city in Italy.
          Lombardy has the highest concentration of nursing homes in Italy – 20%.
          Percentage of smokers in Italy higher than US.
          Healthcare in Lombardy may not necessary be “up to US standards.” Italy’s system strains under the “seasonal flu” every year.

          Do you really want to be comparing the ENTIRE population (and geography) of the United States to ONE city in Italy?

          Hmmm…. No, not really.

          50 people in the nursing home of 100 residents have died. Omg! The fatality rate is 50%. Terrible!!

          2 children in K-12 nationwide have died. Terrible (and it is terrible). The fatality rate is 0.000021%. Omg!

          Yep! Good luck, cause I’m gonna take my chances. I can’t stay home until there is… never a cure.

          1. Interesting. The USA is worse than Lombardy in heart disease, obesity, opioid abuse, and so forth. So Americans can be sacrificed.

            We are now learning what you mean when you chant MAGA over and over. Your idea of greatness has nothing to do with objectively measured health, prosperity, or education opportunities for average Americans. All others outside your club can die for all you care.

            1. I’m in my 40s. Mild heart disease – under control. I’m only slightly overweight. Don’t drink. Have never chanted MAGA in my life. Don’t smoke or use drugs.

              But, I like to eat and live in a house, so I need to go back to work to earn… uh… money.

              If you have a problem with that, YOU can stay home. That’s fine by me. Or maybe it is YOU who are willing to sacrifice me. That’s not fine by me.

              Any suggestions how to rectify this stalemate? Perhaps you could donate some of your savings to those who you want to keep locked up at home.

              Covid-19 – The first pandemic in history where we quarantine the healthy.

            2. If you live in an area where the virus isn’t running wild, where there are ample medical resources in reserve, and where everyone is willing to follow reasonable public health guidance, come out of your house and go back to work. Nobody has a problem with that.

              If you live someplace where cases are rising, the emergency rooms are almost full, and people are crowding into the reopened bars and restaurants as if there were no tomorrow, prepare for the worst. Neither Lysol nor a red hat will protect you.

          2. You might want to hold off getting the Coronavirus for as long as possible, reduced lung capacity for the rest of your life and other possible side effects on the table, good luck.

            1. You are an idiot. NOBODY is out trying to get covid-19 (unless Danox is out sniffing people’s masks).

              What are the side effects of not going to work? Uhh… how do I buy food and pay my home loan? I like food and living in a house. My wife likes food and a roof, too. “Good luck” ain’t gonna cut it.

              Danox, you are an empty, soundbite idiot! I dare you to make one legitimate, thoughtful suggestion for those of us who are out of work until further notice.

          3. Just a few points: Lombardy is not a city. There have been 9 deaths under 18 yoa in NYC alone. Americans over 65 are still voting taxpayers with the same rights as any other citizen. Persons in nursing homes do not lose their status as human beings deserving of protection from arrogant punks who assume the right to live dangerously.

            For an independent calculation of the infection fatality rate in NYC as 1.4%, see


            1. Viruses don’t care about your rights. Viruses don’t care if Lombardy is a city, country or administrative region. Viruses don’t care about grandma in nursing homes. Viruses don’t care about your status as a human or how much you pay in taxes.

              If you are old and in poor health, then you are at high risk. It’s tough. It sucks. It’s sad. But, if you are young and in good health, there is little risk. Excuse me for being 29 years old.

              At what point can the young and healthy get back to life?

        1. There is a long way to go for that. Herd immunity requires at least 60%, more likely 75%, and possibly more of the populace to have antibodies. A highly infectious disease like measles needs 95%. Antibody testing in highly affected regions like New York and Lombardy is finding just over 20%. Spain, with the highest per capita death toll in the world, has a national immunity rate around 5%.

          To reach 75% would require at least 15 times as many American victims as we have already seen. Prudent public health measures (which need not include a total lockdown) seems like a better alternative.

      1. Perfect t-shirt for social hubris-driven misfits without a clue. Your rights DO end when they might result in the death of others and death is a legitimate fear. Get it? So don’t drink and drive either Bunkie. “My Feelings > Your Life” the mantra of a total idiot.

            1. I reported data. I’m not responsible for the data. But since you ask, there was not 1.5 million inauguration attendees. That’s data too, and on topic to my comment.

              But to the real substance…
              Fesarius and I are opposites in things Apple, I do agree with his post.

          1. “Mine was based on MDN’s count, which if flawed is not my responsibility.”
            Same mentality TXer uses when quoting articles that are later disproven.

            Your choice to believe flawed information, like the Russia and Ukraine probes, only leads to mass hysteria by a duped and constantly disappointed (and overly loud) minority.

            Enjoy those wins in your head while the rest of us deal with reality.
            (and get used to disappointment!!)

        1. “Perfect t-shirt for social hubris-driven misfits without a clue.”

          Perfect t-shirt for LIBTARD driven misfits without a clue.

          THERE, I fixed it for you…

        1. So, does it matter if I’m shopping alongside you at Walmart, have the disease and display no symptoms? Well, I have LIMITED rights to shop for food, go to Home Depot, pick up curbside takeout food, and the same what if I have the virus and have no symptoms? Do my rights end not knowing? You think about that…

    1. Liberal and conservative brain function has been shown to differ considerably during exercises in risk-taking. These differences led researchers to conclude that socially conservative views are driven, at least in part, by people’s need to feel safe and secure. While liberals present themselves as more open to experience and change, conservatives seem more likely to protect that which we know. This divide appears to apply to multiculturalism, traditional institutions and financial risk, but not all unknown risks.

      Today, conservatives are the ones ready to confront risk head-on. That’s consistent with my experience in the military, where the overwhelming majority of special operators identify as conservatives. Recent data confirm my experiences, indicating that high-risk civilian occupations tend to be filled by those who lean right:

      If conservatives show more brain activity when processing fear, they also seem better at overcoming it.

      Liberals are also more comfortable with a government that regulates more behavior and provides more services. They often say, “You can’t be free if you don’t have service X, Y and Z.” Such statements sound nonsensical to conservative ears. The conservative emphasis on personal responsibility leaves less room for the government micromanagement we’re witnessing now.

      Conservatives understand basic morality differently, too. Research shows that among the five moral foundations—care, fairness, authority and tradition, in-group loyalty, and purity—liberals prioritize care and fairness, while conservatives engage all five about equally. The liberal weighting means that far more emphasis is placed on a single consideration— “If it saves even one life . . .” — to the exclusion of others, such as the costs to society. Liberals equate those costs with simple monetary hardship, easily replaced by a government check. Conservatives realize economic devastation may affect lives for years, altering their entire trajectories.

      The liberal approach betrays a lack of imagination… Just because you can work remotely doesn’t mean others can, too. Just because you don’t want to confront risk doesn’t mean others should be prevented from doing so. Just because you have a single-dimensional view of “caring” doesn’t mean we can afford to ignore the consequences of economic devastation.

      It is time to reopen America in a smart and deliberate fashion and stop calling people murderers because they want to get back to work. The American people are responsible enough to live free and confront risk. Let them do so. — U.S. Representative Dan Crenshaw, former United States Navy SEAL, The Wall Street Journal, May 18, 2020

      1. Interesting…

        Progressivism heralds moving forward, but it lacks simple courage. The movement “forward” mandates/forces collective mindset, the use of other people’s money, and scorns ideas that are different. The scorn is often delivered via ridicule.

        1. It’s pretty easy to “show courage” when you are being bombarded with the message that the coronavirus is only a threat to marginalized groups that you do not belong to. That is a lie—there are significant numbers of white guys in their prime that have gone to the hospital or died. It is also a lie that there is some miracle cure right around the corner that will solve the problem without any further sacrifice. The forces spreading those lies are either ignorantly or knowingly threatening lives.

          We must move forward, and any path forward will cost lives. There is no way around that. The trick is to plot the course in which the loss of lives directly from the virus or indirectly from the shutdown is minimized. In making that calculation, all human lives should be treated as equally valuable. Old people, black people, diabetic people, city dwellers, poor people, residents of states with Democratic governors, malnourished people, and people without healthcare are also American citizens with the same rights as anyone else.

          As Rep. Crenshaw says, “Americans are responsible enough to live free and confront risk.” However, there is increasing evidence that they are not very responsible about assessing risks that they think only affect somebody else. Those crowds at political rallies, on beaches, and at bars who are standing shoulder to shoulder with strangers while everyone is maskless obviously think they are immune… and that the enhanced risk to the community is worth it. I don’t think they are demonstrating informed consent, and there is no way that the other people they are putting at risk have given consent.

          Everyone is being threatened by the deliberate spread of misinformation, which was also the major cause of death in 1918-1919.

          1. You are a HUGE supplier of misinformation and you know it.
            Mix it in with enough truth and it gets lost with the reality.

            You wonder why I can’t stand you?
            You CLAIM to be a Republican and yet you can’t even HOBBLE the walk.
            Beijing Betty the Bullshitter every time you make a statement.

            Why are you even on a Mac site??
            What the hell, because you have an iPhone 5s??

            1. Ok, Mr. “mild flu,” give us some examples of misinformation I have provided.

              I just bought two new iPhones for my wife and myself. You can’t even get that right.

            2. Mixing fact (your new phones) with fiction (mild flu) is what you do best as a professional liar.

              So tell us Beijing Betty, as a paid liar, what do you think of the Flynn case in your professional understanding?

            3. I think the Flynn case is completely off topic. That is precisely why the Administration wants us to be talking about that rather than its response to the pandemic.

              I’m not taking the bait.

              Glad you finally admit that the novel coronavirus is not a mild flu, however.

          2. “It’s pretty easy to “show courage” when you are being bombarded with the message that the coronavirus is only a threat to marginalized groups that you do not belong to.”

            Talk about off topic and showing your support for liberal groups.

            My favorite:

            Why am I so doubtful whenever you are out of sight…


            Deflection… torments my heart
            Deflection… keeps us apart
            Deflection… why torture me

            User play on lyrics from “Suspicion” by the King Elvis …

          3. People are also ignoring the cases that have come up in children all over the world, kids exhibiting of Kawasaki symptoms etc. and linked to coronavirus.
            There are 10 cases being studied in a Montreal, several in NY and in European cities.

            I don’t care how small a chance my kids have of developing the Kawasaki symptoms if the get Covid. Not worth even the slightest risk.
            FFS this virus about 6 months old. No way can we possibly know side effects and other complications that might come of it.

    2. To be fair PCR simply amplifies whatever nucleus acid is there, and though a virus’ main feature is nucleic acid, proteins and membranes, etc. It’s an assemblage nonetheless. So presence of genetic material most definitely does not mean functional virus, it doesn’t rule it out either.

        1. Do you imagine that confusing polymerase chain reaction lab tests with the People’s Republic of China is funny? You might not have noticed that almost 100,000 Americans have died. Not a joke.

    3. Spare us the tired Democrat talking points you are a SLAVE to, not every person needs to tested. Over 85% who contract the virus LIVES. Herd immunity is happening big time and you and your meaningless comparisons can’t stop it…🇺🇸 USA!

      1. How do you look at yourself in a mirror? If you know the term “herd immunity,” you know that it requires from 60% to 95% of the population have antibodies, depending on the infectioness of the disease. Best guess for COVID-19 is 75%. The actual rate in the most highly infected parts of Italy and New York is just over 20%. So, herd immunity isn’t happening even little time, and those who are spreading your lie are knowingly promoting mass deaths.

  2. Are you ok with “Sanctuary Cities“ where a significant portion of such people drive without car insurance…so, when your mother dies as a result of one such uninsured, the family is left without legal/financial solutions (besides no mother)?

    How about actions in those same cities, and others, where criminals are caught, but suffer no ramifications for their, sometimes serious crimes, but are let go because of “Covid-in-the-prison-fears” and such people go on to commit heinous crimes…against someone’s mother? Hello Houston’s recent event.

    Let’s just go ahead and say…who the F is talking about the right to “kill you,” Mr. Exaggerator? Demanding everything to come to a halt, for you, one that’s in a top tier of danger for Covid, is nothing but a selfish demand. Stay home, wear a mask when the deliveries of food and other things are exchanged at the door and the vast majority of life can continue for those not in the same danger range.

    1. You have no idea the probability or possible outcomes of different risks, do you?

      You should know that <<< 1% of vehicle drivers have fatal accidents. Far more this year will have a coronavirus infection. Those who have traffic accidents are often partially or fully to blame. COVID-19 victims are not at fault for the reckless behaviors of others. If you don’t think this is a real crisis, then volunteer at your local senior services center to see what these citizens deal with every day. A bit of empathy towards others would do you a lot of good.

        1. Maybe because he has an army of top doctors advising him. Maybe.

          You know as much about Trump’s health as he knows about yours. Darn close to nothin.

  3. The probability of risk, of which you seem to claim knowledge, it tilted VERY, VERY heavily towards a certain segment of the population. Let’s focus on that segment and let others minimize the other kind of risk that pushes them to bankruptcy, foreclosure, other health consequences affecting persons and their family. How ‘bout that?

    Empathy exhibits in various ways. Claiming you have empathy w/o observing something other than “your way,” isn’t empathy at all.

  4. Since the vast majority of people couldn’t get a test if they wanted it, nobody has great data to guide what precautions are needed to be strict in which locations. Given lack of data, the science proposes that everyone be careful and prudent as possible until the data comes in. The loudmouth anti-science crowd, as always, demands the freedom to be selfish and reckless. Sadly these magats seldom pay the price. They would feel no remorse if they found that they were a carrier who infected and killed someone in his immediate community. The unstated value of the trumpets is not America First, it is Me First. It shows in every thing they do. It explains why they endlessly back the most corrupt regime in modern US history.

    But it is also true that the rapidly growing idiot class of America is doing a poor job too. They may not be malicious like Me First 2014, but they are clueless.

    Given how few people wear protective equipment or wash their hands properly, it’s a given that vulnerable people would be wise to quarantine themselves. The MeFirst crowd who thinks they are bulletproof and don’t give a rats a$$ about their elders. The clueless class doesn’t think.

    So, elderly citizens: stay home while your offspring spread the second wave of infections.

  5. What? Sick and vulnerable people protect themselves? I’m shocked! But, it does sound like a great idea.

    As for the other people responsible for the second wave, sure, they can go about the business of keeping the country afloat. You know… things like earning a salary to pay for grandma’s meals and meds. Little things like that.

    Gee, seems a bit like war. Some go out to sacrifice to keep others safe. And some die. And the sun will rise tomorrow.

    1. It is exactly like war. Guys like Herr Krupp and Cadet Bonespurs sit safe at home making money and delivering patriotic speeches while somebody else dies so their lifestyle won’t be disrupted. As usual, the people ordering the sacrifices don’t expect to put their own lives on the line. Read the lyrics to Dylan’s Masters of War!

      And no, the sun might not rise tomorrow for you if you are dead because somebody decided you were expendable. As Wilfred Owen wrote,

      If in some smothering dreams, you too could pace
      Behind the wagon that we flung him in,
      And watch the white eyes writhing in his face,
      His hanging face, like a devil’s sick of sin;
      If you could hear, at every jolt, the blood
      Come gargling from the froth-corrupted lungs,
      Obscene as cancer, bitter as the cud
      Of vile, incurable sores on innocent tongues,—
      My friend, you would not tell with such high zest
      To children ardent for some desperate glory,
      The old Lie: * Dulce et decorum est
      Pro patria mori.*

      1. “sit safe at home making money and delivering patriotic speeches while somebody else dies so their lifestyle won’t be disrupted.”

        Typical liberal jealousy and hatred for success…

      2. No, it would be contempt for the summer soldiers and sunshine patriots who wave the flag, talk of war, and condemn other Americans as cowards while they themselves do everything in their power to avoid personal danger.

        The sort of able-bodied men who attended military school and played four sports in college, and then claimed they were too disabled to go to Vietnam. The sort who argue for rejecting public health recommendations while they sit all day in splendid isolation surrounded by people in masks who undergo daily testing.

        The sort who have a delusive belief that a killer virus is much less dangerous to them personally than it actually is, recognize that others are much more vulnerable, yet still insist that the weak have to be sacrificed for the strong. The sort who have noticed that the disease is targeting populations that tend to vote for their political opponents, and oppose steps that might save them.

        The sort who can defend war profiteers. Krupp? Really?

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