If reality is a data structure, can the simulation theory hold up?
Exploring the idea that objects we perceive in everyday life do not reflect objective reality.
Donald Hoffman
Donald Hoffman is professor of cognitive science at the University of California, Irvine. His writing has appeared in Scientific American and Edge, and his work has been featured in the Atlantic, Wired, and Quanta. He resides in Irvine, California.
- Professor of cognitive science Donald Hoffman presents his theory that the world we perceive is a virtual reality. Hoffman has tested this theory by running successful computer simulations that suggest there is no objective reality.
- When it comes to Nick Bostrom's simulation theory, Hoffman agrees with parts and disagrees with others. Hoffman argues that, while space time and physical objects do not correspond with objective reality, conscious experiences like the smell of garlic and the feel of velvet cannot be produced by the simulation.
- "You can't start with unconscious ingredients and boot up consciousness," Hoffman says.
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'Deep Nostalgia' AI brings old photos to life through animation
Using machine-learning technology, the genealogy company My Heritage enables users to animate static images of their relatives.
03 March, 2021
Deep Nostalgia/My Heritage
Technology & Innovation
- Deep Nostalgia uses machine learning to animate static images.
- The AI can animate images by "looking" at a single facial image, and the animations include movements such as blinking, smiling and head tilting.
- As deepfake technology becomes increasingly sophisticated, some are concerned about how bad actors might abuse the technology to manipulate the pubic.
<p>A new service gives new life to the past by using artificial intelligence to convert static images into moving videos.</p><p>Called <a href="https://www.myheritage.se/deep-nostalgia" target="_blank">Deep Nostalgia</a>, the service creates animations by using deep learning to analyze a single facial photo. Then, the system animates the facial image through a "driver" — a pre-determined sequence of movements and gestures, like blinking, smiling and head-turning. The process is completely automated, and the service enhances the images to make the animations run more smoothly.</p><p>Launched in February by the Israeli genealogy company My Heritage, some of Deep Nostalgia's early results are impressive.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTcxMjYwNi9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTY3NjU0MTA1Nn0.YtmzhaxuspC1IgzqIxmil5KWE_J-pdttmIlhZZgu2BI/img.gif?width=980" id="da492" class="rm-shortcode" data-rm-shortcode-id="e17271ac382d6059e2118920788f3167" data-rm-shortcode-name="rebelmouse-image" data-width="600" data-height="338" />
My Heritage/Deep Nostalgia
<p>But that's not to say the animations are perfect. As with most deep-fake technology, there's still an uncanny air to the images, with some of the facial movements appearing slightly unnatural. What's more, Deep Nostalgia is only able to create deepfakes of one person's face from the neck up, so you couldn't use it to animate group photos, or photos of people doing any sort of physical activity.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTcxMzA5Ni9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTY0NDk0ODUzNH0.037klDGjbuVpSI7zd_dSoM6HmYE7jDoWuCQ-49tmvpI/img.gif?width=980" id="e1991" class="rm-shortcode" data-rm-shortcode-id="fde2943845c0ef3eb36ccc7d90d950f5" data-rm-shortcode-name="rebelmouse-image" data-width="600" data-height="400" />
My Heritage/Deep Nostalgia
<p>But for a free deep-fake service, Deep Nostalgia is pretty impressive, especially considering you can use it to create deepfakes of <em>any </em>face, human or not. </p><div id="fd951" class="rm-shortcode" data-rm-shortcode-id="8bcc9aa2fcf223a596bd91cb8e7633ea"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1366315861548572672" data-partner="rebelmouse"><div style="margin:1em 0">I just ran the @Warcraft cover through the Deep Nostalgia Tool, and this happened... https://t.co/1eD3bb7fAN</div> — Solitaire #The06 (@Solitaire #The06)<a href="https://twitter.com/SolitaireYTG/statuses/1366315861548572672">1614590060.0</a></blockquote></div>
<blockquote class="twitter-tweet"><p lang="nl" dir="ltr">H. erectus<a href="https://t.co/sS9eVT1Iu0">https://t.co/sS9eVT1Iu0</a> <a href="https://t.co/CguYm9zm8T">pic.twitter.com/CguYm9zm8T</a></p>— Fake History Hunter (@fakehistoryhunt) <a href="https://twitter.com/fakehistoryhunt/status/1366374349146628099?ref_src=twsrc%5Etfw">March 1, 2021</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
<div id="82ea4" class="rm-shortcode" data-rm-shortcode-id="337617b6bc536b1cb8fb8b2fa799d1b4"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1365574843027124227" data-partner="rebelmouse"><div style="margin:1em 0">Generated with MyHeritage.
#DeepNostalgia https://t.co/gNX3wLHsS8</div> — Andrey Frolov (@Andrey Frolov)<a href="https://twitter.com/kznsq/statuses/1365574843027124227">1614413388.0</a></blockquote></div><p>So, is creating deepfakes of long-dead people a bit creepy? Some people seem to think so.</p><p style="margin-left: 20px;">"Some people love the feature with Deep Nostalgia ™ and consider it magical while others think it is scary and dislike it," My Heritage wrote on its <a href="https://www.myheritage.se/deep-nostalgia" target="_blank" rel="noopener noreferrer">website</a>. "In fact, the results can be controversial and it is difficult to be indifferent to this technology. We invite you to create movies using this feature and share them on social media to see what your friends and relatives think. This feature is intended for nostalgic use, that is, to give life back to beloved ancestors."</p><p>Deep Nostalgia isn't the first project to create deepfakes from single images. In 2019, researchers working at the Samsung AI Center in Moscow published a <a href="https://arxiv.org/abs/1905.08233" target="_blank" rel="noopener noreferrer">paper</a> describing how machine-learning techniques can produce deepfakes after "looking" at only one or a few images. Using a framework known as a generative adversarial network, the researchers trained a pair of computer models to compete with each other to create convincing deepfakes. </p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="5c794ffe2841f3fb0080fba58910efa7"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/p1b5aiTrGzY?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>While the results from the Samsung researchers were impressive, the Deep Nostalgia project shows how deepfake technology is advancing at a rapid pace. As these tools have become increasingly sophisticated, <a href="https://bigthink.com/technology-innovation/deepfake-images-presidents" target="_blank">media experts have raised concerns</a> about how bad actors might use deepfakes and "cheap fakes" to manipulate the public. </p><p>My Heritage seemed to sense Deep Nostalgia's potential for abuse, writing:</p><p style="margin-left: 20px;">"Please use this feature on your own historical photos and not on photos of living people without their consent."</p>
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When does an idea die? Plato and string theory clash with data
How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
03 March, 2021
13-8
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
<ul class="ee-ul"></ul>
<p>From the perspective of the west, it all started in ancient Greece, around 600 BCE. This is during the Axial Age, a somewhat controversial term coined by German philosopher Karl Jaspers to designate the remarkable intellectual and spiritual awakening that happened in different places across the globe roughly within the span of a century. Apart from the Greek explosion of thought, this is the time of Siddhartha Gautama (aka the Buddha) in India, of Confucius and Lao Tzu in China, of Zoroaster (or Zarathustra) in ancient Persia—religious leaders and thinkers who would reframe the meaning of faith and morality. In Greece, Thales of Miletus and Pythagoras of Samos pioneered pre-Socratic philosophy, (sort of) moving the focus of inquiry and explanation from the divine to the natural. </p><p>To be sure, the divine never quite left early Greek thinking, but with the onset of philosophy, trying to understand the workings of nature through logical reasoning—as opposed to supernatural reasoning—would become an option that didn't exist before. The history of science, from its early days to the present, could be told as an increasingly successful split between belief in a supernatural component to reality and a strictly materialistic cosmos. The Enlightenment of the 17th and 18th centuries, the Age of Reason, means quite literally 'to see the light,' the light here clearly being the superiority of human logic above any kind of supernatural or nonscientific methodology to get to the "truth" of things.</p>
<blockquote>Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. </blockquote>
<p>To what extent we can understand the workings of nature through logic alone is not something science can answer. It is here that the complication begins. Can the human mind, through the diligent application of scientific methodology and the use of ever-more-powerful instruments, reach a complete understanding of the natural world? Is there an "end to science"? This is the sensitive issue. If the split that started in pre-Socratic Greece were to be completed, nature in its entirety would be amenable to a logical description, the complete collection of behaviors that science studies identified, classified, and described by means of perpetual natural laws. All that would be left for scientists and engineers to do would be practical applications of this knowledge, inventions, and technologies that would serve our needs in different ways.</p>
<p>This sort of vision—or hope, really—goes all the way back to at least Plato who, in turn, owes much of this expectation to Pythagoras and Parmenides, the philosopher of Being. The dispute between the primacy of that which is timeless or unchangeable (Being), and that which is changeable and fluid (Becoming), is at least that old. Plato proposed that truth was in the unchangeable, rational world of Perfect Forms that preceded the tricky and deceptive reality of the senses. For example, the abstract form <em>Chair</em> embodies all chairs, objects that can take many shapes in our sensorial reality while serving their functionality (an object to sit on) and basic design (with a sittable surface and some legs below it). According to Plato, the Forms hold the key to the essence of all things.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTcwODg5Ni9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzNDA3OTQzNX0.Fy8WPmFn0mT0fy5e3Qq3HN70lzJ7Epk2iICVl6BwM_Q/img.png?width=980" id="4f64f" class="rm-shortcode" data-rm-shortcode-id="5a29206a396ef429914fa48a441c00be" data-rm-shortcode-name="rebelmouse-image" data-width="782" data-height="1024" />
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0
<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p><p>This kind of tension is palpable today when we see groups of scientists passionately arguing <a href="https://www.amazon.com/dp/0316013331?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank">for</a> or <a href="https://www.amazon.com/dp/1541646762?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank">against</a> the existence of the multiverse, an idea that states that our universe is one in a huge number of other universes; or <a href="https://www.amazon.com/dp/0735223793?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank">for</a> or <a href="https://www.amazon.com/dp/0465092764?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank">against</a> the final unification of the laws of physics.</p><p>Nature, of course, is always the final arbiter of any scientific dispute. Data decides, one way or another. That's the beauty and power at the core of science. The challenge, though, is to know when to let go of an idea. How long should one wait until an idea, seductive as it may be, is deemed unrealistic? This is where the debate gets interesting. Data to support more "out there" ideas such as the multiverse or extra symmetries of nature needed for unification models has refused to show up for decades, despite extensive searches with different instruments and techniques. On the other hand, we only find if we look. So, should we keep on defending these ideas? Who decides? Is it a community decision or should each person pursue their own way of thinking?</p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="fa3185b1f66d82d9e77023abfa9da5bf"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/YSWd21z2qqE?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>In 2019, I participated in an interesting <a href="https://www.worldsciencefestival.com/programs/loose-ends-string-theory-and-the-quest-for-the-ultimate-theory/" target="_blank">live debate at the World Science Festival</a> with physicists Michael Dine and Andrew Strominger and hosted by physicist Brian Greene. The theme was string theory, our best candidate for a final theory of how particles of matter interact. When I completed my PhD in 1986, string theory was <em>the</em> way. The only way. But, by 2019, things had changed, and quite dramatically, due to the lack of supporting data. To my surprise, both Mike and Andy were quite open to the fact that that certainty of the past was no more. String theory has taught physicists many things and that was perhaps its use. The Platonic outlook was in peril.</p><p>The dispute remains alive, although with each experiment that fails to show supporting evidence for string theory the dream grows harder to justify. Will it be a generational thing, as celebrated physicist Max Planck once quipped, "Ideas don't die, physicists do"? (I paraphrase.) I hope not. But it is a conversation that should be held more in the open, as was the case with the World Science Festival. Dreams die hard. But they may die a little easier when we accept the fact that our grasp of reality is limited, and doesn't always fit our expectations of what should or shouldn't be real.</p>
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Physicist creates AI algorithm that may prove reality is a simulation
A physicist creates an AI algorithm that predicts natural events and may prove the simulation hypothesis.
01 March, 2021
Credit: Adobe Stock
Surprising Science
- Princeton physicist Hong Qin creates an AI algorithm that can predict planetary orbits.
- The scientist partially based his work on the hypothesis which believes reality is a simulation.
- The algorithm is being adapted to predict behavior of plasma and can be used on other natural phenomena.
<p>A scientist devised a computer algorithm which may lead to transformative discoveries in energy and whose very existence raises the likelihood that our reality could actually be a simulation.</p><p>The algorithm was created by the physicist Hong Qin, from the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL).</p><p>The algorithm employs an AI process called machine learning, which improves its knowledge in an automated way, through experience. </p>
<p><span style="background-color: initial;">Qin developed this algorithm to predict the orbits of planets in the solar system, </span><span style="background-color: initial;">training it on data of </span><span style="background-color: initial;">Mercury, Venus, Earth, Mars, Ceres, and Jupiter orbits</span><span style="background-color: initial;">. The data is "similar to what Kepler inherited from Tycho Brahe in 1601," as Qin writes in his newly-published <a href="https://www.nature.com/articles/s41598-020-76301-0" target="_blank">paper</a> on the subject. From this data, a "serving algorithm" can correctly predict other planetary orbits in the solar system, including parabolic and hyperbolic escaping orbits. What's remarkable, it can do so without having to be told about Newton's laws of motion and universal gravitation. It can figure those laws out for itself from the numbers.</span></p><p>Qin is now adapting the algorithm to predict and even control other behaviors, with a current focus on particles of plasma in facilities built for harvesting fusion energy powering the Sun and stars. Along with Eric Palmerduca, a Ph.D. graduate student at PPPL, Qin is using his technique "to learning an effective structure-preserving algorithm with long-term stability to simulate the gyrocenter dynamics in magnetic fusion plasmas," as he elaborated. He also plans to utilize the algorithm to study quantum physics.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTcwMDM1Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzY0MDY2OH0.8FvARYNypcco8XPhDqhwfA6gm5m_y2n14zUvWFntYSI/img.jpg?width=980" id="b2f2a" class="rm-shortcode" data-rm-shortcode-id="d6f017be69928b77d077275649777b58" data-rm-shortcode-name="rebelmouse-image" data-width="792" data-height="612" />
Physicist Hong Qin with images of planetary orbits and computer code.
Credit: Elle Starkman
<p>Qin explained the unusual approach taken by his work:</p><p style="margin-left: 20px;">"Usually in physics, you make observations, create a theory based on those observations, and then use that theory to predict new observations, " <a href="https://www.pppl.gov/news/2021/02/new-machine-learning-theory-can-be-applied-fusion-energy-raises-questions-about-very" target="_blank">said Qin.</a> "What I'm doing is replacing this process with a type of black box that can produce accurate predictions without using a traditional theory or law. Essentially, I bypassed all the fundamental ingredients of physics. I go directly from data to data (…) There is no law of physics in the middle."</p><p>Qin was partially inspired by the work of Swedish philosopher Nick Bostrom, whose <a href="https://bigthink.com/mind-brain/are-we-living-in-a-simulation" target="_blank">2003 paper</a> famously argued that the world we are living in may be an artificial simulation. What Qin believes he has accomplished with his algorithm is provide a working example of an underlying technology that could support the simulation in Bostrom's philosophical argument.</p>
<p>In an email exchange with Big Think, Qin remarked: "What is the algorithm running on the laptop of the Universe? If such an algorithm exists, I would argue that it should be a simple one defined on the discrete spacetime lattice. The complexity and richness of the Universe come from the enormous memory size and CPU power of the laptop, but the algorithm itself could be simple."</p><p>Certainly, the existence of an algorithm that derives meaningful predictions of natural events from data does not yet mean that we ourselves have the capabilities to simulate existence. Qin believes we are likely "many generations" away from being able to carry out such feats.</p><p>Qin's work takes the approach of using "discrete field theory," which he thinks is particularly well suited for machine learning, while somewhat difficult for "a current human" to understand. He explained that "a discrete field theory can be viewed as an algorithmic framework with adjustable parameters that can be trained using observational data." He added that "once trained, the discrete field theory becomes an algorithm of nature that computers can run to predict new observations."</p>
Are we living in a simulation? | Bill Nye, Joscha Bach, Donald Hoffman | Big Think
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="4dbe18924f2f42eef5669e67f405b52e"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/KDcNVZjaNSU?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>According to Qin, discrete field theories go against the most popular method of studying physics today, which looks at spacetime as continuous. This approach was started with Isaac Newton, who invented three approaches to describing continuous spacetime, including Newton's law of motion, Newton's law of gravitation, and calculus.</p><p>Qin believes there are serious issues in modern research that stem from the laws of physics in continuous spacetime being expressed through differential equations and continuous field theories. If laws of physics were based on discrete spacetime, as Qin proposes, "many of the difficulties can be overcome." </p><p>If the world works according to discrete field theory, it would look like something out "The Matrix," made of pixels and data points. </p>
<p>Qin's work also coincides with the logic of Bostrom's simulation hypothesis and would mean that "the discrete field theories are more fundamental than our current laws of physics in continuous space." In fact, writes Qin, "our offspring must find the discrete field theories more natural than the laws in continuous space used by their ancestors during the 17<span style="background-color: initial;"><sup>th</sup></span>-21<span style="background-color: initial;"><sup>st</sup></span> centuries."</p><p>Check out Hong Qin's paper on the subject in <a href="https://www.nature.com/articles/s41598-020-76301-0" target="_blank">Scientific Reports.</a></p>
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Can you still spread coronavirus after getting the vaccine?
The vaccine will shorten the "shedding" time.
03 March, 2021
Fredrik Lerneryd/Getty Images
Coronavirus
Editor's note: So you've gotten your coronavirus vaccine, waited the two weeks for your immune system to respond to the shot and are now fully vaccinated.
<p><em>Does this mean you can make your way through the world like the old days without fear of spreading the virus? <a href="https://scholar.google.com/citations?user=eNprtJEAAAAJ&hl=en&oi=ao">Deborah Fuller is a microbiologist</a> at the University of Washington School of Medicine working on coronavirus vaccines. She explains what the science shows about transmission post-vaccination – and whether new variants could change this equation.</em></p><h2>1. Does vaccination completely prevent infection?</h2><p>The short answer is no. You can still get infected after you've been vaccinated. But your chances of getting seriously ill are almost zero.</p><p>Many people think vaccines work like a shield, blocking a virus from infecting cells altogether. But in most cases, a person who gets vaccinated is <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/sterilizing-immunity">protected from disease, not necessarily infection</a>.</p><p>Every person's immune system is a little different, so when a vaccine is <a href="https://www.nytimes.com/2020/11/20/health/covid-vaccine-95-effective.html">95% effective</a>, that just means 95% of people who receive the vaccine <a href="https://doi.org/10.1056/NEJMoa2101765">won't get sick</a>. These people could be completely protected from infection, or they could be getting infected but remain asymptomatic because their immune system eliminates the virus very quickly. The remaining 5% of vaccinated people can become infected and get sick, but are <a href="https://doi.org/10.1056/NEJMoa2101765">extremely unlikely to be hospitalized</a>. </p><p>Vaccination doesn't 100% prevent you from getting infected, but in all cases it gives your immune system a huge leg up on the coronavirus. Whatever your outcome – whether complete protection from infection or some level of disease – you will be better off after encountering the virus than if you hadn't been vaccinated.</p><p> <a href="https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An electron microscope scan of the coronavirus" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" src="https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=469&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=469&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=469&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=589&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=589&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386271/original/file-20210224-22-1uk65si.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=589&fit=crop&dpr=3 2262w"></a></p><p> Vaccines prevent disease, not infection. (<a class="source" href="https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2#/media/File:Novel_Coronavirus_SARS-CoV-2.jpg">National Institute of Allergy and Infectious Diseases</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a>)</p>
<h2>2. Does infection always mean transmission?</h2><p>Transmission happens when enough viral particles from an infected person get into the body of an uninfected person. In theory, anyone infected with the coronavirus could potentially transmit it. But a vaccine will reduce the chance of this happening.</p><p>In general, if vaccination doesn't completely prevent infection, it will significantly reduce the amount of virus coming out of your nose and mouth – a process called shedding – and shorten the time that you shed the virus. This is a big deal. A person who sheds less virus is <a href="https://www.scientificamerican.com/article/vaccines-need-not-completely-stop-covid-transmission-to-curb-the-pandemic1/" target="_blank" rel="noopener noreferrer">less likely to transmit it to someone else</a>.</p><p>This seems to be the case with coronavirus vaccines. In a <a href="https://doi.org/10.1101/2021.02.06.21251283" target="_blank" rel="noopener noreferrer">recent preprint study</a> which has yet to be peer reviewed, Israeli researchers tested 2,897 vaccinated people for signs of coronavirus infection. Most had no detectable virus, but people who were infected had one-quarter the amount of virus in their bodies as unvaccinated people tested at similar times post-infection.</p><p>Less coronavirus virus means less chance of spreading it, and if the amount of virus in your body is low enough, the probability of transmitting it may reach almost zero. However, researchers don't yet know where that cutoff is for the coronavirus, and since the vaccines don't provide 100% protection from infection, the Centers for Disease Control and Prevention recommends that people continue to wear masks and social distance even <a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/keythingstoknow.html" target="_blank" rel="noopener noreferrer">after they've been vaccinated</a>.</p>
<h2>3. What about the new coronavirus variants?</h2><p>New variants of coronavirus have emerged in recent months, and recent studies show that vaccines are less effective against certain ones, like <a href="https://www.cidrap.umn.edu/news-perspective/2021/02/pfizer-moderna-vaccines-may-be-less-effective-against-b1351-variant" target="_blank" rel="noopener noreferrer">the B1351 variant</a> first identified in South Africa.</p><p>Every time SARS-CoV-2 replicates, it gets new mutations. In recent months, researchers have found new variants that are <a href="https://www.cdc.gov/coronavirus/2019-ncov/more/science-and-research/scientific-brief-emerging-variants.html" target="_blank" rel="noopener noreferrer">more infective</a> – meaning a person needs to breathe in less virus to become infected – and other variants that are <a href="https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiab082/6134354" target="_blank" rel="noopener noreferrer">more transmissible</a> - meaning they increase the amount of virus a person sheds. And researchers have also found at least one new variant that seems to be <a href="https://doi.org/10.1101/2021.02.14.21251704" target="_blank" rel="noopener noreferrer">better at evading the immune system</a>, according to early data.</p><p>So how does this relate to vaccines and transmission?</p>
<p>For the South Africa variant, vaccines still provide <a href="https://www.sciencemag.org/news/2021/01/one-dose-covid-19-vaccine-offers-solid-protection-against-severe-disease" target="_blank">greater than 85% protection</a> from getting severely ill with COVID–19. But when you count mild and moderate cases, they provide, at best, only about <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00370-6/fulltext" target="_blank">50%-60% protection</a>. That means at least 40% of vaccinated people will still have a strong enough infection – and enough virus in their body – to cause at least moderate disease.</p><p>If vaccinated people have more virus in their bodies and it takes less of that virus to infect another person, there will be higher probability a vaccinated person could transmit these new strains of the coronavirus.</p><p>If all goes well, vaccines will very soon reduce the rate of severe disease and death worldwide. To be sure, any vaccine that reduces disease severity is also, at the population level, reducing the amount of virus being shed overall. But because of the emergence of new variants, vaccinated people still have the potential to shed and spread the coronavirus to other people, vaccinated or otherwise. This means it will likely take <a href="https://www.scientificamerican.com/article/vaccines-need-not-completely-stop-covid-transmission-to-curb-the-pandemic1/" target="_blank">much longer for vaccines to reduce transmission</a> and <a href="https://doi.org/10.1038/d41586-021-00396-2" target="_blank" rel="noopener noreferrer">for populations to reach herd immunity</a> than if these new variants had never emerged. Exactly how long that will take is a balance between how effective vaccines are against emerging strains and how transmissible and infectious these new strains are.</p><p><a href="https://theconversation.com/profiles/deborah-fuller-1207799" target="_blank" rel="noopener noreferrer">Deborah Fuller</a>, Professor of Microbiology, School of Medicine, <em><a href="https://theconversation.com/institutions/university-of-washington-699" target="_blank" rel="noopener noreferrer">University of Washington</a></em></p><p>This article is republished from <a href="https://theconversation.com/" target="_blank" rel="noopener noreferrer">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/can-vaccinated-people-still-spread-the-coronavirus-155095" target="_blank" rel="noopener noreferrer">original article</a>.</p>
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