People Who Test Positive for COVID-19 After Recovering Aren't Infectious
By Julia Ries
Around the world, there have been several cases of people recovering from COVID-19 only to later test positive again and appear to have another infection.
Such cases have had doctors and researchers puzzling over whether recovered people continue to be contagious, and if they could get a second infection.
Now, new research published by the Korea Centers for Disease Control and Prevention has found that recovered COVID-19 patients who test positive again aren't infectious.
The study also found that most patients who recover have neutralizing antibodies — the type of antibody that confers immunity and protects people from getting sick again.
"This study addresses the question of whether patients who have recovered from COVID-19 are still infectious, and which is a question that has been troubling us for some time," said Dr. Heidi J. Zapata, a Yale Medicine infectious disease doctor. "This study suggests that patients that are recovered are no longer contagious."
The Viral Material in Re-Positive Cases Isn’t Infectious
The Korean study examined 285 patients who tested positive again for the new coronavirus after they recovered from COVID-19, which had been confirmed via a negative test result.
The researchers swabbed the patients and examined the viral material to determine whether it was still actively infectious.
The team was unable to isolate live viral material, indicating that the positive diagnostic tests were picking up dead virus particles.
"[This] may speak for the fact that the virus may be dead or not be fit enough to grow — therefore the virus may not be fit enough to infect a new host," said Dr. Andres Romero, an infectious disease specialist at Providence Saint John's Health Center in Santa Monica, California.
The researchers also tested 790 people who'd been in close contact with the "re-positive" patients. Of the 27 who tested positive, no cases appeared to be caused from exposure to someone who appeared to have a reinfection.
The report also found that the vast majority of recovered patients (96 percent) had neutralizing antibodies, indicating that they conferred immunity.
"Whether this is indicative of a completely protective response remains to be proven. If this study holds true, then people who have recovered can get back to work," Zapata said.
In response to the new findings, South Korea eliminated a policy requiring discharged patients to isolate for 2 weeks.
Conducting and Interpreting PCR Tests
The tests widely used to diagnose COVID-19 are called polymerase chain reaction (PCR) tests.
The tests swab a person's nose or throat and try to pick up the virus's genetic material, or RNA.
According to guidance from the U.S. Centers for Disease Control and Prevention (CDC), a positive result on a PCR test doesn't "necessarily mean infectious virus is present or that the patient is contagious."
Infectious disease experts have suspected that the test kits aren't picking up actively infectious viral material in recovered patients who test positive again, but rather dead remnants of the virus.
We see this occur with other viruses, too.
"We know other viruses like parainfluenza, human metapneumovirus, or RSV [respiratory syncytial virus] may linger for months in certain patients, and that does not represent infectious state," Romero said. "Coronavirus may be the same."
We Still Need to Practice Caution
While the findings are promising, infectious disease experts say we still need to practice caution.
More research is needed to validate these findings and determine whether they apply to distinct parts of the population, such as those who are immunocompromised.
It's common for immunocompromised patients — such as those with cancer — to continue testing positive for a virus for longer, since it takes their immune system more time to clear the virus out of their body.
"I don't think we can be 100 percent certain of whether each recovered person is no longer contagious. Again, this may differ with distinct population groups," Zapata said.
Physicians are seeing some hospitalized patients testing positive for a month after they were first swabbed for COVID-19. It's unclear whether these patients still shed infectious virus, according to Zapata.
Everyone's body mounts a distinct immune response based on their age and overall health. Different individuals will clear the virus out at different speeds, according to Zapata.
Until we have more data and a preventive vaccine, it's crucial to continue adhering to the safety precautions laid out by the CDC.
"The reality is that moving forward, the best approach will be keeping social/physical distancing, wearing a mask, and frequent hand hygiene in order to control the spread of the virus," Romero said.
The Bottom Line
Doctors and researchers have been unsure whether people who recover from COVID-19 who test positive again continue to be contagious, or if they could get a second infection.
New research published by the Korea Centers for Disease Control and Prevention has found that recovered COVID-19 patients who test positive again aren't infectious.
The study also found that most patients who recover have neutralizing antibodies that protect them from getting sick again.
Though the study is promising, health experts say we need more data to validate the findings and determine whether they apply to all patient populations.
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This week marks the official start of fall, but longer nights and colder days can make it harder to spend time outdoors. Luckily, there are several inspiring environmental films that can be streamed at home.
1. Kiss the Ground<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="ccc5f0c92a5603e68aec39e56b0db02a"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/K3-V1j-zMZw?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p><strong>Streaming On: Netflix</strong></p><p><strong>Premiere Date: Sept. 22</strong></p><p>Between <a href="https://www.ecowatch.com/wildfires-california-washington-oregon-photos-2647585008.html" target="_self">wildfires devastating the U.S. West Coast</a> and <a href="https://www.ecowatch.com/tropical-storm-beta-landfall-2647760268.html" target="_self">storms battering the Gulf</a>, the impacts of the <a href="https://www.ecowatch.com/climate-change/" target="_self">climate crisis</a> can feel overwhelming right now. <em><a href="https://kissthegroundmovie.com/" rel="noopener noreferrer" target="_blank">Kiss the Ground</a> </em>offers an alternative to all of the bad news by focusing on solutions.</p><p>The film, directed by Josh and Rebecca Tickell and narrated by Woody Harrelson, explains how we can heal the Earth through "regenerative agriculture," farming practices that draw carbon dioxide from the atmosphere and into soil as a way to restore soil health, which in turn boosts ecosystems and food supplies.</p><p>"<em>Kiss the Ground </em>shows how feasible it is to make these changes at a grassroots level immediately and make a truly substantive impact with low cost and easy to implement solutions," Executive Producer RJ Jain said in an email. "This is why I got involved."</p>
2. Public Trust: The Fight for America's Public Lands<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="5338f7a2931e356910026e5fd76fac56"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/jsKMTAaj_wQ?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p><strong>Streaming On: YouTube</strong></p><p><strong>Premiere Date: Sept. 25, 2 p.m. EDT </strong></p><p>This <a href="https://www.patagonia.com/films/public-trust/" target="_blank">award-winning documentary</a> tells the stories of Indigenous activists, journalists, whistleblowers and historians working to protect America's <a href="https://www.ecowatch.com/tag/public-lands" target="_self">public lands</a>. The film focuses on three political struggles: the shrinking of <a href="https://www.ecowatch.com/tag/bears-ears" target="_self">Bears Ears</a> National Monument in Utah, the mining of Boundary Waters Wilderness in Minnesota and the opening of the <a href="https://www.ecowatch.com/tag/Arctic-National-Wildlife-Refuge" target="_self">Arctic National Wildlife Refuge</a> to fossil fuel exploration.</p><p><em>Public Trust</em> was directed by David Garrett Byars and produced by Jeremy Rubingh. Patagonia Films, Patagonia founder Yvon Chouinard and actor Robert Redford are executive producers. It will be <a href="https://www.youtube.com/watch?v=OGjnIG7puzY" rel="noopener noreferrer" target="_blank">released</a> on YouTube in time for <a href="https://www.ecowatch.com/national-public-lands-day-2640656776.html" target="_self">National Public Lands Day</a>.</p><p>"Our country is fortunate to have millions of acres of public lands, including National Parks, Monuments, Wildlife Refuges and Wilderness set aside for future generations," Redford said. "Sadly, these lands that belong to you and me are under unprecedented threats from the greed of big corporations, eager to weaken restrictions in the pursuit of profits. Many of our current politicians are also to blame. <em>Public Trust</em> tells the story of citizens who are fighting back. It's a much-needed wake-up call for all of us who want to preserve our unique and wild cultural heritage."</p>
3. David Attenborough: A Life on Our Planet<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="156438a30836a765d7a92982545fc334"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/B_OFZvAd05Y?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p><strong>Streaming On: Netflix</strong></p><p><strong>Premiere Date: Oct. 4</strong></p><p>Beloved nature broadcaster <a href="https://www.ecowatch.com/tag/David-Attenborough" target="_self">David Attenborough</a> has spent his career introducing viewers to the wonders of our planet. In recent years, his footage of albatrosses swallowing <a href="https://www.ecowatch.com/tag/plastics" target="_self">plastic</a> in <em>Blue Planet II</em> has been credited with <a href="https://www.ecowatch.com/2018-fighting-plastic-waste-2624606566.html" target="_self">helping to ramp up</a> the global fight against plastic pollution. Now, in this <a href="https://www.wwf.org.uk/" rel="noopener noreferrer" target="_blank">World Wildlife Fund</a> (WWF)-produced <a href="https://www.attenborough.film/" rel="noopener noreferrer" target="_blank">documentary</a>, he reflects on the defining moments of his career and the devastating changes he has witnessed.</p><p><em>David Attenborough: A Life on Our Planet,</em> which was also produced by Silverback Films and directed by Alastair Fothergill, Jonnie Hughes and Keith Scholey, features an intimate conversation between Attenborough and Sir Michael Palin as the broadcaster reflects on his life and a career that took him to every continent on Earth. In addition to streaming on Netflix, the movie will be available in select theaters starting Sept. 28.</p><p>"For decades, David has brought the natural world to the homes of audiences worldwide, but there has never been a more significant moment for him to share his own story and reflections," WWF executive producer Colin Butfield said in a <a href="https://www.wwf.org.uk/updates/david-attenborough-life-our-planet" target="_blank">statement</a>. "This film coincides with a monumental year for environmental action as world leaders make critical decisions on nature and climate. It sends a powerful message from the most inspiring and celebrated naturalist of our time."</p>
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If all the glaciers and ice caps on the planet melted, global sea level would rise by about 230 feet. That amount of water would flood nearly every coastal city around the world [source: U.S. Geological Survey]. Rising temperatures, melting arctic ice, drought, desertification and other catastrophic effects of climate change are not examples of future troubles — they are reality today. Climate change isn't just about the environment; its effects touch every part of our lives, from the stability of our governments and economies to our health and where we live.
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