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Taking a Closer Look at COVID-19’s Effects on the Brain

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MRI of a brain damaged by COVID-19
Caption: Magnetic resonance microscopy showing lower part of a COVID-19 patient’s brain stem postmortem. Arrows point to light and dark spots indicative of blood vessel damage with no signs of infection by the coronavirus that causes COVID-19. Credit: National Institute of Neurological Disorders and Stroke, NIH

While primarily a respiratory disease, COVID-19 can also lead to neurological problems. The first of these symptoms might be the loss of smell and taste, while some people also may later battle headaches, debilitating fatigue, and trouble thinking clearly, sometimes referred to as “brain fog.” All of these symptoms have researchers wondering how exactly the coronavirus that causes COVID-19, SARS-CoV-2, affects the human brain.

In search of clues, researchers at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) have now conducted the first in-depth examinations of human brain tissue samples from people who died after contracting COVID-19. Their findings, published in the New England Journal of Medicine, suggest that COVID-19’s many neurological symptoms are likely explained by the body’s widespread inflammatory response to infection and associated blood vessel injury—not by infection of the brain tissue itself [1].

The NIH team, led by Avindra Nath, used a high-powered magnetic resonance imaging (MRI) scanner (up to 10 times as sensitive as a typical MRI) to examine postmortem brain tissue from 19 patients. They ranged in age from 5 to 73, and some had preexisting conditions, such as diabetes, obesity, and cardiovascular disease.
The team focused on the brain’s olfactory bulb that controls our ability to smell and the brainstem, which regulates breathing and heart rate. Based on earlier evidence, both areas are thought to be highly susceptible to COVID-19.

Indeed, the MRI images revealed in both regions an unusual number of bright spots, a sign of inflammation. They also showed dark spots, which indicate bleeding. A closer look at the bright spots showed that tiny blood vessels in those areas were thinner than normal and, in some cases, leaked blood proteins into the brain. This leakage appeared to trigger an immune reaction that included T cells from the blood and the brain’s scavenging microglia. The dark spots showed a different pattern, with leaky vessels and clots but no evidence of an immune reaction.

While those findings are certainly interesting, perhaps equally noteworthy is what Nath and colleagues didn’t see in those samples. They could find no evidence in the brain tissue samples that SARS-CoV-2 had invaded the brain tissue. In fact, several methods to detect genetic material or proteins from the virus all turned up empty.

The findings are especially intriguing because there has been some suggestion based on studies in mice that SARS-CoV-2 might cross the blood-brain barrier and invade the brain. Indeed, a recent report by NIH-funded researchers in Nature Neuroscience showed that the viral spike protein, when injected into mice, readily entered the brain along with many other organs [2].

Another recent report in the Journal of Experimental Medicine, which used mouse and human brain tissue, suggests that SARS-CoV-2 may indeed directly infect the central nervous system, including the brain [3]. In autopsies of three people who died from complications of COVID-19, the NIH-supported researchers detected signs of SARS-CoV-2 in neurons in the brain’s cerebral cortex. This work was done using the microscopy-based technique of immunohistochemistry, which uses antibodies to bind to a target, in this case, the virus’s spike protein. Also last month, in a study published in the journal Neurobiology of Disease, another NIH-supported team demonstrated in a series of experiments in cell culture that the SARS-CoV-2 spike protein could cross a 3D model of the blood-brain barrier and infect the endothelial cells that line blood vessels in the brain [4].

Clearly, more research is needed, and Nath and colleagues continue to explore how COVID-19 affects the brain and triggers the neurological symptoms often seen in people with COVID-19. As we learn more about the many ways COVID-19 wreaks havoc on the body, understanding the neurological symptoms will be critical in helping people, including the so-called Long Haulers bounce back from this terrible viral infection.


[1] Microvascular Injury in the Brains of Patients with Covid-19. Lee MH, Perl DP, Nair G, Li W, Maric D, Murray H, Dodd SJ, Koretsky AP, Watts JA, Cheung V, Masliah E, Horkayne-Szakaly I, Jones R, Stram MN, Moncur J, Hefti M, Folkerth RD, Nath A. N Engl J Med. 2020 Dec 30.

[2] The S1 protein of SARS-CoV-2 crosses the blood-brain barrier in mice. Rhea EM, Logsdon AF, Hansen KM, Williams LM, Reed MJ, Baumann KK, Holden SJ, Raber J, Banks WA, Erickson MA. Nat Neurosci. 2020 Dec 16.

[3] Neuroinvasion of SARS-CoV-2 in human and mouse brain. Song E, Zhang C, Israelow B, et al. J Exp Med (2021) 218 (3): e20202135.

[4] The SARS-CoV-2 spike protein alters barrier function in 2D static and 3D microfluidic in-vitro models of the human blood-brain barrier. Buzhdygan TP, DeOre BJ, Baldwin-Leclair A, Bullock TA, McGary HM, Khan JA, Razmpour R, Hale JF, Galie PA, Potula R, Andrews AM, Ramirez SH. Neurobiol Dis. 2020 Dec;146:105131.


COVID-19 Research (NIH)

Avindra Nath (National Institute of Neurological Disorders and Stroke/NIH)

NIH Support: National Institute of Neurological Disorders and Stroke; National Institute on Aging; National Institute of General Medical Sciences; National Cancer Institute; National Institute of Mental Health

What A Year It Was for Science Advances!

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Science Breakthroughs of the Year 2020

At the close of every year, editors and writers at the journal Science review the progress that’s been made in all fields of science—from anthropology to zoology—to select the biggest advance of the past 12 months. In most cases, this Breakthrough of the Year is as tough to predict as the Oscar for Best Picture. Not in 2020. In a year filled with a multitude of challenges posed by the emergence of the deadly coronavirus disease 2019 (COVID-2019), the breakthrough was the development of the first vaccines to protect against this pandemic that’s already claimed the lives of more than 360,000 Americans.

In keeping with its annual tradition, Science also selected nine runner-up breakthroughs. This impressive list includes at least three areas that involved efforts supported by NIH: therapeutic applications of gene editing, basic research understanding HIV, and scientists speaking up for diversity. Here’s a quick rundown of all the pioneering advances in biomedical research, both NIH and non-NIH funded:

Shots of Hope. A lot of things happened in 2020 that were unprecedented. At the top of the list was the rapid development of COVID-19 vaccines. Public and private researchers accomplished in 10 months what normally takes about 8 years to produce two vaccines for public use, with more on the way in 2021. In my more than 25 years at NIH, I’ve never encountered such a willingness among researchers to set aside their other concerns and gather around the same table to get the job done fast, safely, and efficiently for the world.

It’s also pretty amazing that the first two conditionally approved vaccines from Pfizer and Moderna were found to be more than 90 percent effective at protecting people from infection with SARS-CoV-2, the coronavirus that causes COVID-19. Both are innovative messenger RNA (mRNA) vaccines, a new approach to vaccination.

For this type of vaccine, the centerpiece is a small, non-infectious snippet of mRNA that encodes the instructions to make the spike protein that crowns the outer surface of SARS-CoV-2. When the mRNA is injected into a shoulder muscle, cells there will follow the encoded instructions and temporarily make copies of this signature viral protein. As the immune system detects these copies, it spurs the production of antibodies and helps the body remember how to fend off SARS-CoV-2 should the real thing be encountered.

It also can’t be understated that both mRNA vaccines—one developed by Pfizer and the other by Moderna in conjunction with NIH’s National Institute of Allergy and Infectious Diseases—were rigorously evaluated in clinical trials. Detailed data were posted online and discussed in all-day meetings of an FDA Advisory Committee, open to the public. In fact, given the high stakes, the level of review probably was more scientifically rigorous than ever.

First CRISPR Cures: One of the most promising areas of research now underway involves gene editing. These tools, still relatively new, hold the potential to fix gene misspellings—and potentially cure—a wide range of genetic diseases that were once to be out of reach. Much of the research focus has centered on CRISPR/Cas9. This highly precise gene-editing system relies on guide RNA molecules to direct a scissor-like Cas9 enzyme to just the right spot in the genome to cut out or correct a disease-causing misspelling.

In late 2020, a team of researchers in the United States and Europe succeeded for the first time in using CRISPR to treat 10 people with sickle cell disease and transfusion-dependent beta thalassemia. As published in the New England Journal of Medicine, several months after this non-heritable treatment, all patients no longer needed frequent blood transfusions and are living pain free [1].

The researchers tested a one-time treatment in which they removed bone marrow from each patient, modified the blood-forming hematopoietic stem cells outside the body using CRISPR, and then reinfused them into the body. To prepare for receiving the corrected cells, patients were given toxic bone marrow ablation therapy, in order to make room for the corrected cells. The result: the modified stem cells were reprogrammed to switch back to making ample amounts of a healthy form of hemoglobin that their bodies produced in the womb. While the treatment is still risky, complex, and prohibitively expensive, this work is an impressive start for more breakthroughs to come using gene editing technologies. NIH, including its Somatic Cell Genome Editing program, continues to push the technology to accelerate progress and make gene editing cures for many disorders simpler and less toxic.

Scientists Speak Up for Diversity: The year 2020 will be remembered not only for COVID-19, but also for the very public and inescapable evidence of the persistence of racial discrimination in the United States. Triggered by the killing of George Floyd and other similar events, Americans were forced to come to grips with the fact that our society does not provide equal opportunity and justice for all. And that applies to the scientific community as well.

Science thrives in safe, diverse, and inclusive research environments. It suffers when racism and bigotry find a home to stifle diversity—and community for all—in the sciences. For the nation’s leading science institutions, there is a place and a calling to encourage diversity in the scientific workplace and provide the resources to let it flourish to everyone’s benefit.

For those of us at NIH, last year’s peaceful protests and hashtags were noticed and taken to heart. That’s one of the many reasons why we will continue to strengthen our commitment to building a culturally diverse, inclusive workplace. For example, we have established the NIH Equity Committee. It allows for the systematic tracking and evaluation of diversity and inclusion metrics for the intramural research program for each NIH institute and center. There is also the recently founded Distinguished Scholars Program, which aims to increase the diversity of tenure track investigators at NIH. Recently, NIH also announced that it will provide support to institutions to recruit diverse groups or “cohorts” of early-stage research faculty and prepare them to thrive as NIH-funded researchers.

AI Disentangles Protein Folding: Proteins, which are the workhorses of the cell, are made up of long, interconnected strings of amino acids that fold into a wide variety of 3D shapes. Understanding the precise shape of a protein facilitates efforts to figure out its function, its potential role in a disease, and even how to target it with therapies. To gain such understanding, researchers often try to predict a protein’s precise 3D chemical structure using basic principles of physics—including quantum mechanics. But while nature does this in real time zillions of times a day, computational approaches have not been able to do this—until now.

Of the roughly 170,000 proteins mapped so far, most have had their structures deciphered using powerful imaging techniques such as x-ray crystallography and cryo–electron microscopy (cryo-EM). But researchers estimate that there are at least 200 million proteins in nature, and, as amazing as these imaging techniques are, they are laborious, and it can take many months or years to solve 3D structure of a single protein. So, a breakthrough certainly was needed!

In 2020, researchers with the company Deep Mind, London, developed an artificial intelligence (AI) program that rapidly predicts most protein structures as accurately as x-ray crystallography and cryo-EM can map them [2]. The AI program, called AlphaFold, predicts a protein’s structure by computationally modeling the amino acid interactions that govern its 3D shape.

Getting there wasn’t easy. While a complete de novo calculation of protein structure still seemed out of reach, investigators reasoned that they could kick start the modeling if known structures were provided as a training set to the AI program. Utilizing a computer network built around 128 machine learning processors, the AlphaFold system was created by first focusing on the 170,000 proteins with known structures in a reiterative process called deep learning. The process, which is inspired by the way neural networks in the human brain process information, enables computers to look for patterns in large collections of data. In this case, AlphaFold learned to predict the underlying physical structure of a protein within a matter of days. This breakthrough has the potential to accelerate the fields of structural biology and protein research, fueling progress throughout the sciences.

How Elite Controllers Keep HIV at Bay: The term “elite controller” might make some people think of video game whizzes. But here, it refers to the less than 1 percent of people living with human immunodeficiency virus (HIV) who’ve somehow stayed healthy for years without taking antiretroviral drugs. In 2020, a team of NIH-supported researchers figured out why this is so.

In a study of 64 elite controllers, published in the journal Nature, the team discovered a link between their good health and where the virus has inserted itself in their genomes [3]. When a cell transcribes a gene where HIV has settled, this so-called “provirus,” can produce more virus to infect other cells. But if it settles in a part of a chromosome that rarely gets transcribed, sometimes called a gene desert, the provirus is stuck with no way to replicate. Although this discovery won’t cure HIV/AIDS, it points to a new direction for developing better treatment strategies.

In closing, 2020 presented more than its share of personal and social challenges. Among those challenges was a flood of misinformation about COVID-19 that confused and divided many communities and even families. That’s why the editors and writers at Science singled out “a second pandemic of misinformation” as its Breakdown of the Year. This divisiveness should concern all of us greatly, as COVID-19 cases continue to soar around the country and our healthcare gets stretched to the breaking point. I hope and pray that we will all find a way to come together, both in science and in society, as we move forward in 2021.


[1] CRISPR-Cas9 gene editing for sickle cell disease and β-thalassemia. Frangoul H et al. N Engl J Med. 2020 Dec 5.

[2] ‘The game has changed.’ AI triumphs at protein folding. Service RF. Science. 04 Dec 2020.

[3] Distinct viral reservoirs in individuals with spontaneous control of HIV-1. Jiang C et al. Nature. 2020 Sep;585(7824):261-267.


COVID-19 Research (NIH)

2020 Science Breakthrough of the Year (American Association for the Advancement of Science, Washington, D.C)

The People’s Picks for Best Posts

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It’s 2021—Happy New Year! Time sure flies in the blogosphere. It seems like just yesterday that I started the NIH Director’s Blog to highlight recent advances in biology and medicine, many supported by NIH. Yet it turns out that more than eight years have passed since this blog got rolling and we are fast approaching my 1,000th post!

I’m pleased that millions of you have clicked on these posts to check out some very cool science and learn more about NIH and its mission. Thanks to the wonders of social media software, we’ve been able to tally up those views to determine each year’s most-popular post. So, I thought it would be fun to ring in the New Year by looking back at a few of your favorites, sort of a geeky version of a top 10 countdown or the People’s Choice Awards. It was interesting to see what topics generated the greatest interest. Spoiler alert: diet and exercise seemed to matter a lot! So, without further ado, I present the winners:

2013: Fighting Obesity: New Hopes from Brown Fat. Brown fat, one of several types of fat made by our bodies, was long thought to produce body heat rather than store energy. But Shingo Kajimura and his team at the University of California, San Francisco, showed in a study published in the journal Nature, that brown fat does more than that. They discovered a gene that acts as a molecular switch to produce brown fat, then linked mutations in this gene to obesity in humans.

What was also nice about this blog post is that it appeared just after Kajimura had started his own lab. In fact, this was one of the lab’s first publications. One of my goals when starting the blog was to feature young researchers, and this work certainly deserved the attention it got from blog readers. Since highlighting this work, research on brown fat has continued to progress, with new evidence in humans suggesting that brown fat is an effective target to improve glucose homeostasis.

2014: In Memory of Sam Berns. I wrote this blog post as a tribute to someone who will always be very near and dear to me. Sam Berns was born with Hutchinson-Gilford progeria syndrome, one of the rarest of rare diseases. After receiving the sad news that this brave young man had passed away, I wrote: “Sam may have only lived 17 years, but in his short life he taught the rest of us a lot about how to live.”

Affecting approximately 400 people worldwide, progeria causes premature aging. Without treatment, children with progeria, who have completely normal intellectual development, die of atherosclerotic cardiovascular disease, on average in their early teens.

From interactions with Sam and his parents in the early 2000s, I started to study progeria in my NIH lab, eventually identifying the gene responsible for the disorder. My group and others have learned a lot since then. So, it was heartening last November when the Food and Drug Administration approved the first treatment for progeria. It’s an oral medication called Zokinvy (lonafarnib) that helps prevent the buildup of defective protein that has deadly consequences. In clinical trials, the drug increased the average survival time of those with progeria by more than two years. It’s a good beginning, but we have much more work to do in the memory of Sam and to help others with progeria. Watch for more about new developments in applying gene editing to progeria in the next few days.

2015: Cytotoxic T Cells on Patrol. Readers absolutely loved this post. When the American Society of Cell Biology held its first annual video competition, called CellDance, my blog featured some of the winners. Among them was this captivating video from Alex Ritter, then working with cell biologist Jennifer Lippincott-Schwartz of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. The video stars a roving, specialized component of our immune system called cytotoxic T cells. Their job is to seek out and destroy any foreign or detrimental cells. Here, these T cells literally convince a problem cell to commit suicide, a process that takes about 10 minutes from detection to death.

These cytotoxic T cells are critical players in cancer immunotherapy, in which a patient’s own immune system is enlisted to control and, in some cases, even cure the cancer. Cancer immunotherapy remains a promising area of research that continues to progress, with a lot of attention now being focused on developing immunotherapies for common, solid tumors like breast cancer. Ritter is currently completing a postdoctoral fellowship in the laboratory of Ira Mellman, Genentech, South San Francisco. His focus has shifted to how cancer cells protect themselves from T cells. And video buffs—get this—Ritter says he’s now created even cooler videos that than the one in this post.

2016: Exercise Releases Brain-Healthy Protein. The research literature is pretty clear: exercise is good for the brain. In this very popular post, researchers led by Hyo Youl Moon and Henriette van Praag of NIH’s National Institute on Aging identified a protein secreted by skeletal muscle cells to help explore the muscle-brain connection. In a study in Cell Metabolism, Moon and his team showed that this protein called cathepsin B makes its way into the brain and after a good workout influences the development of new neural connections. This post is also memorable to me for the photo collage that accompanied the original post. Why? If you look closely at the bottom right, you’ll see me exercising—part of my regular morning routine!

2017: Muscle Enzyme Explains Weight Gain in Middle Age. The struggle to maintain a healthy weight is a lifelong challenge for many of us. While several risk factors for weight gain, such as counting calories, are within our control, there’s a major one that isn’t: age. Jay Chung, a researcher with NIH’s National Heart, Lung, and Blood Institute, and his team discovered that the normal aging process causes levels of an enzyme called DNA-PK to rise in animals as they approach middle age. While the enzyme is known for its role in DNA repair, their studies showed it also slows down metabolism, making it more difficult to burn fat.

Since publishing this paper in Cell Metabolism, Chung has been busy trying to understand how aging increases the activity of DNA-PK and its ability to suppress renewal of the cell’s energy-producing mitochondria. Without renewal of damaged mitochondria, excess oxidants accumulate in cells that then activate DNA-PK, which contributed to the damage in the first place. Chung calls it a “vicious cycle” of aging and one that we’ll be learning more about in the future.

2018: Has an Alternative to Table Sugar Contributed to the C. Diff. Epidemic? This impressive bit of microbial detective work had blog readers clicking and commenting for several weeks. So, it’s no surprise that it was the runaway People’s Choice of 2018.

Clostridium difficile (C. diff) is a common bacterium that lives harmlessly in the gut of most people. But taking antibiotics can upset the normal balance of healthy gut microbes, allowing C. diff. to multiply and produce toxins that cause inflammation and diarrhea.

In the 2000s, C. diff. infections became far more serious and common in American hospitals, and Robert Britton, a researcher at Baylor College of Medicine, Houston, wanted to know why. He and his team discovered that two subtypes of C. diff have adapted to feed on the sugar trehalose, which was approved as a food additive in the United States during the early 2000s. The team’s findings, published in the journal Nature, suggested that hospitals and nursing homes battling C. diff. outbreaks may want to take a closer look at the effect of trehalose in the diet of their patients.

2019: Study Finds No Benefit for Dietary Supplements. This post that was another one that sparked a firestorm of comments from readers. A team of NIH-supported researchers, led by Fang Fang Zhang, Tufts University, Boston, found that people who reported taking dietary supplements had about the same risk of dying as those who got their nutrients through food. What’s more, the mortality benefits associated with adequate intake of vitamin A, vitamin K, magnesium, zinc, and copper were limited to amounts that are available from food consumption. The researchers based their conclusion on an analysis of the well-known National Health and Nutrition Examination Survey (NHANES) between 1999-2000 and 2009-2010 survey data. The team, which reported its data in the Annals of Internal Medicine, also uncovered some evidence suggesting that certain supplements might even be harmful to health when taken in excess.

2020: Genes, Blood Type Tied to Risk of Severe COVID-19. Typically, my blog focuses on research involving many different diseases. That changed in 2020 due to the emergence of a formidable public health challenge: the coronavirus disease 2019 (COVID-19) pandemic. Since last March, the blog has featured 85 posts on COVID-19, covering all aspects of the research response and attracting more visitors than ever. And which post got the most views? It was one that highlighted a study, published last June in the New England Journal of Medicine, that suggested the clues to people’s variable responses to COVID-19 may be found in our genes and our blood types.

The researchers found that gene variants in two regions of the human genome are associated with severe COVID-19 and correspondingly carry a greater risk of COVID-19-related death. The two stretches of DNA implicated as harboring risks for severe COVID-19 are known to carry some intriguing genes, including one that determines blood type and others that play various roles in the immune system.

In fact, the findings suggest that people with blood type A face a 50 percent greater risk of needing oxygen support or a ventilator should they become infected with the novel coronavirus. In contrast, people with blood type O appear to have about a 50 percent reduced risk of severe COVID-19.

That’s it for the blog’s year-by-year Top Hits. But wait! I’d also like to give shout outs to the People’s Choice winners in two other important categories—history and cool science images.

Top History Post: HeLa Cells: A New Chapter in An Enduring Story. Published in August 2013, this post remains one of the blog’s greatest hits with readers. The post highlights science’s use of cancer cells taken in the 1950s from a young Black woman named Henrietta Lacks. These “HeLa” cells had an amazing property not seen before: they could be grown continuously in laboratory conditions. The “new chapter” featured in this post is an agreement with the Lacks family that gives researchers access to the HeLa genome data, while still protecting the family’s privacy and recognizing their enormous contribution to medical research. And the acknowledgments rightfully keep coming from those who know this remarkable story, which has been chronicled in both book and film. Recently, the U.S. Senate and House of Representatives passed the Henrietta Lacks Enhancing Cancer Research Act to honor her extraordinary life and examine access to government-funded cancer clinical trials for traditionally underrepresented groups.

Top Snapshots of Life: A Close-up of COVID-19 in Lung Cells. My blog posts come in several categories. One that you may have noticed is “Snapshots of Life,” which provides a showcase for cool images that appear in scientific journals and often dominate Science as Art contests. My blog has published dozens of these eye-catching images, representing a broad spectrum of the biomedical sciences. But the blog People’s Choice goes to a very recent addition that reveals exactly what happens to cells in the human airway when they are infected with the coronavirus responsible for COVID-19. This vivid image, published in the New England Journal of Medicine, comes from the lab of pediatric pulmonologist Camille Ehre, University of North Carolina at Chapel Hill. This image squeezed in just ahead of another highly popular post from Steve Ramirez, Boston University, in 2019 that showed “What a Memory Looks Like.”

As we look ahead to 2021, I want to thank each of my blog’s readers for your views and comments over the last eight years. I love to hear from you, so keep on clicking! I’m confident that 2021 will generate a lot more amazing and bloggable science, including even more progress toward ending the COVID-19 pandemic that made our past year so very challenging.

Accepting the COVID-19 Vaccine

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Francis Collins Vaccination
I was thrilled to roll up my sleeve and get the Moderna COVID-19 vaccine today at the NIH Clinical Center. As NIH Director, I’ve followed closely the development of these first vaccines, and I know they have been rigorously tested and found to be safe and effective. I encourage everyone to accept the vaccines when offered to you. It’s our best chance to turn the tide on the pandemic. Also receiving the vaccine today were Health and Human Services Secretary Alex Azar, Anthony Fauci, Director of NIH’s National Institute of Allergy and Infectious Diseases; Colleen McGowan, Director of NIH’s Office of Research Services; and six frontline healthcare workers at the NIH Clinical Center. Credit: NIH

Celebrating the Gift of COVID-19 Vaccines

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COVID-19 - Gift of the Vaccines
Credit: NIH

The winter holidays are traditionally a time of gift-giving. As fatiguing as 2020 and the COVID-19 pandemic have been, science has stepped up this year to provide humankind with a pair of truly hopeful gifts: the first two COVID-19 vaccines.

Two weeks ago, the U.S. Food and Drug Administration (FDA) granted emergency use authorization (EUA) to a COVID-19 vaccine from Pfizer/BioNTech, enabling distribution to begin to certain high-risk groups just three days later. More recently, the FDA granted an EUA to a COVID-19 vaccine from the biotechnology company Moderna, Cambridge, MA. This messenger RNA (mRNA) vaccine, which is part of a new approach to vaccination, was co-developed by NIH’s National Institute of Allergy and Infectious Diseases (NIAID). The EUA is based on data showing the vaccine is safe and 94.5 percent effective at protecting people from infection with SARS-CoV-2, the coronavirus that causes COVID-19.

Those data on the Moderna vaccine come from a clinical trial of 30,000 individuals, who generously participated to help others. We can’t thank those trial participants enough for this gift. The distribution of millions of Moderna vaccine doses is expected to begin this week.

It’s hard to put into words just how remarkable these accomplishments are in the history of science. A vaccine development process that used to take many years, often decades, has been condensed to about 11 months. Just last January, researchers started out with a previously unknown virus and we now have not just one, but two, vaccines that will be administered to millions of Americans before year’s end. And the accomplishments don’t end there—several other types of COVID-19 vaccines are also on the way.

It’s important to recognize that this couldn’t have happened without the efforts of many scientists working tirelessly behind the scenes for many years prior to the pandemic. Among those who deserve tremendous credit are Kizzmekia Corbett, Barney Graham, John Mascola, and other members of the amazing team at the Dale and Betty Bumpers Vaccine Research Center at NIH’s National Institute of Allergy and Infectious Diseases (NIAID).

When word of SARS-CoV-2 emerged, Corbett, Graham, and other NIAID researchers had already been studying other coronaviruses for years, including those responsible for earlier outbreaks of respiratory disease. So, when word came that this was a new coronavirus outbreak, they were ready to take action. It helped that they had paid special attention to the spike proteins on the surface of coronaviruses, which have turned out to be the main focus the COVID-19 vaccines now under development.

The two vaccines currently authorized for administration in the United States work in a unique way. Their centerpiece is a small, non-infectious snippet of mRNA. Our cells constantly produce thousands of mRNAs, which provide the instructions needed to make proteins. When someone receives an mRNA vaccine for COVID-19, it tells the person’s own cells to make the SARS-CoV-2 spike protein. The person’s immune system then recognizes the viral spike protein as foreign and produces antibodies to eliminate it.

This vaccine-spurred encounter trains the human immune system to remember the spike protein. So, if an actual SARS-CoV-2 virus tries to infect a vaccinated person weeks or months later, his or her immune system will be ready to fend it off. To produce the most vigorous and durable immunity against the virus, people will need to get two shots of mRNA vaccine, which are spaced several weeks to a month apart, depending on the vaccine.

Some have raised concerns on social media that mRNA vaccines might alter the DNA genome of someone being vaccinated. But that’s not possible, since this mRNA doesn’t enter the nucleus of the cell where DNA is located. Instead, the vaccine mRNAs stay in the outer part of the cell (the cytoplasm). What’s more, after being transcribed into protein just one time, the mRNA quickly degrades. Others have expressed concerns about whether the vaccine could cause COVID-19. That is not a risk because there’s no whole virus involved, just the coding instructions for the non-infectious spike protein.

An important advantage of mRNA is that it’s easy for researchers to synthesize once they know the nucleic acid sequence of a target viral protein. So, the gift of mRNA vaccines is one that will surely keep on giving. This new technology can now be used to speed the development of future vaccines. After the emergence of the disease-causing SARS, MERS, and now SARS-CoV-2 viruses, it would not be surprising if there are other coronavirus health threats in our future. Corbett and her colleagues are hoping to design a universal vaccine that can battle all of them. In addition, mRNA vaccines may prove effective for fighting future pandemics caused by other infectious agents and for preventing many other conditions, such as cancer and HIV.

Though vaccines are unquestionably our best hope for getting past the COVID-19 pandemic, public surveys indicate that some people are uneasy about accepting this disease-preventing gift. Some have even indicated they will refuse to take the vaccine. Healthy skepticism is a good thing, but decisions like this ought to be based on weighing the evidence of benefit versus risk. The results of the Pfizer and Moderna trials, all released for complete public scrutiny, indicate the potential benefits are high and the risks, low. Despite the impressive speed at which the new COVID-19 vaccines were developed, they have undergone and continue to undergo a rigorous process to generate all the data needed by the FDA to determine their long-term safety and effectiveness.

Unfortunately, the gift of COVID-19 vaccines comes too late for the more than 313,000 Americans who have died from complications of COVID-19, and many others who’ve had their lives disrupted and may have to contend with long-term health consequences related to COVID-19. The vaccines did arrive in record time, but all of us wish they could somehow have arrived even sooner to avert such widespread suffering and heartbreak.

It will be many months before all Americans who are willing to get a vaccine can be immunized. We need 75-80 percent of Americans to receive vaccines in order to attain the so-called “herd immunity” needed to drive SARS-CoV-2 away and allow us all to get back to a semblance of normal life.

Meanwhile, we all have a responsibility to do everything possible to block the ongoing transmission of this dangerous virus. Each of us needs to follow the three W’s: Wear a mask, Watch your distance, Wash your hands often.

When your chance for immunization comes, please roll up your sleeve and accept the potentially life-saving gift of a COVID-19 vaccine. In fact, I just got my first shot of the Moderna vaccine today along with NIAID Director Anthony Fauci, HHS Secretary Alex Azar, and some front-line healthcare workers at the NIH Clinical Center. Accepting this gift is our best chance to put this pandemic behind us, as we look forward to a better new year.


Coronavirus (COVID-19) (NIH)

Combat COVID (U.S. Department of Health and Human Services, Washington, D.C.)

Dale and Betty Bumpers Vaccine Research Center (National Institute of Allergy and Infectious Diseases/NIH)

Moderna (Cambridge, MA)

Pfizer (New York, NY)

BioNTech (Mainz, Germany)

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