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Stem cells help restore damaged teeth, new study finds
Stem cells have endless uses. This study suggests they can even bring half dead teeth back to life.
Photo credit: Isaac Castillejos on Unsplash
- A new study demonstrates that stem cells from baby teeth can be used to repair damaged permanent teeth in young children.
- The findings suggest a new treatment for childhood dental issues may be around the corner.
- The treatment's potential applications go much further than just dental health.
Half of all children suffer some kind of dental injury while young. Sometimes the damage isn't to the baby teeth they will lose anyway, but to the permanent adult teeth lying below the gums that they will need for the rest of their lives. In some cases, trauma can cut off the blood supply to a tooth and rot out the living pulp inside it; a condition called "pulp necrosis." This condition often leads to the loss of the tooth. While treatment exists, it is often unsatisfactory.
But stem cells might do the trick.
Few people really like going to the dentist. This new treatment might reduce the need for the less pleasant treatments.
(Getty images)
A new clinical trial by Yan Jin, Kun Xuan, and Bei Li of the Fourth Military Medicine University in Xi'an, China and Songtao Shi of the University of Pennsylvania's School of Dental Medicine demonstrates how to repair teeth suffering from pulp necrosis by taking stem cells from the patient's baby teeth.
The study, carried out in China on 40 children who had both damaged adult teeth and baby teeth that had yet to fall out, was published in the journal Science Translational Medicine. The test subjects were selected to either receive the new treatment or an older treatment called apexification, which attempts to address the issue by encouraging root development. This was considered the control group.
The patients who received the stem cell treatment, called human deciduous pulp stem cell (hDPSC) treatment, had pulp tissue taken out of one of their healthy baby teeth. This pulp is rich in stem cells. The cells were grown in a lab and then placed into the injured adult tooth. The hope was that the stem cells would encourage the growth of new pulp inside the tooth.
Follow-ups were carried out for up to three years. The patients who had received the hDPSC treatment showed better blood flow in their teeth, better root systems, and thicker dentin than the patents who underwent the traditional procedure. They also had recovered sensation in their teeth, while the control group had not. The use of a patient's own cells in the treatment also reduced the risk of their body rejecting the therapy, making the concept even more attractive.
"This treatment gives patients sensation back in their teeth. If you give them a warm or cold stimulation, they can feel it; they have living teeth again," Dr. Shi told Penn Today. "For me, the results are very exciting. To see something we discovered take a step forward to potentially become a routine therapy in the clinic is gratifying."
What applications will this have?
Before you get too excited, the research is still in the early stages. The problem of how to treat adults with dental problems after they have no more baby teeth to take stem cells from still remains unsolved. It will also be some time before the dental treatment gets approval for use in the United States, so don't hold your breath for getting a stem cell boost to your smile just yet.
Many children suffer dental injuries that can have a lasting impact later in life, often leading to the loss of permanent teeth. This can lead to a loss of self-esteem, speech issues, and jaw problems. This new treatment option, while currently limited to very young children, could provide a breakthrough in dental care. The potential applications for treating systemic diseases such as lupus are also promising.
"We're really eager to see what we can do in the dental field, and then building on that to open up channels for systemic disease therapy," Dr. Shi said.
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Scientists find 16 'ultra-black' fish species that absorb 99.9% of light
These alien-like creatures are virtually invisible in the deep sea.
18 July, 2020
A female Pacific blackdragon
Credit: Karen Osborn/Smithsonian
Surprising Science
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
<p>A team of marine biologists has discovered 16 species of "ultra-black" fish that absorb more than 99 percent of the light that hits their skin, making them virtually invisible to other deep-sea fish.</p><p>The researchers, who published their findings Thursday in <a href="http://dx.doi.org/10.1016/j.cub.2020.06.044" target="_blank">Current Biology</a>, caught the species after dropping nets more than 200 meters deep near California's Monterey Bay. At those depths, sunlight fizzles out. That's one reason why many deep-sea species have evolved the ability to illuminate the dark waters through bioluminescence.</p><p>But what if deep-sea fish don't want to be spotted? To counter bioluminescence, some species have evolved ultra-black skin that's exceptionally good at absorbing light. Only a few other species are known to possess this strange trait, including birds of paradise and some spiders and butterflies.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzQ4MDU4Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NDYzNjM2Mn0.k6jg2-EPVkICcGqH-HrmfT5pOtXFkzhgqMnWLZ6Y1Io/img.jpg?width=980" id="ebb94" class="rm-shortcode" data-rm-shortcode-id="7a35766115dfb990d09e0c97b757c361" data-rm-shortcode-name="rebelmouse-image" alt="Ultra-black fishThe Pacific blackdragon" data-width="1200" data-height="800" />
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian
<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzQ4MDU4OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3Mjc2NjEzOX0.rfvIgQdHNWhKRw2-M3Kl_zsoiv4HyUdw2D8IwT_Y5Pc/img.jpg?width=980" id="3ff90" class="rm-shortcode" data-rm-shortcode-id="7c6a84471af0dc875c4746f6e2f193e1" data-rm-shortcode-name="rebelmouse-image" alt="Ultra-black fish" data-width="1024" data-height="683" />
A crested bigscale
Credit: Karen Osborn/Smithsonian
<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzQ4MDU4OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0ODEwNjk2NH0.z5sUB6JLzBURu8UbO90bXRbN73gYheaNeSPqIXLONFY/img.jpg?width=980" id="c9453" class="rm-shortcode" data-rm-shortcode-id="60cab829961aa7377fc08b10e0e1aa10" data-rm-shortcode-name="rebelmouse-image" alt="Ultra-black fish" data-width="1920" data-height="1008" />
Pacific viperfish
David Csepp, NMFS/AKFSC/ABL
<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </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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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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Politics & Current Affairs
The best defense against authoritarianism? More educated citizens.
For democracy to prosper in the long term, we need more people to reach higher levels of education.
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