- Unlocking the Secrets of COVID-19: Why Some Populations Are Hit Harder Than Others SciTechDaily
- SARS-CoV-2: How the history of human populations influences their immune response Phys.org
- Post-Covid condition and clinic characteristics associated with SARS-CoV-2 infection: a 2-year follow-up to Brazilian cases | Scientific Reports Nature.com
- Antinucleocapsid Antibody Response Can Help Diagnose Postacute Sequelae of SARS-CoV-2, Improve Treatment Access AJMC.com Managed Markets Network
- SARS-CoV-2 Mac1 is required for IFN antagonism and efficient virus replication in cell culture and in mice | Proceedings of the National Academy of Sciences pnas.org
- View Full Coverage on Google News
Tag Archives: populations
Early DNA reveals two distinct populations in Britain after the last ice age
An artist’s redesign of the double helix of DNA. Researchers in Britain have discovered two distinct groups of humans living in post-ice age Britain. File Photo by Miroslaw Miras/Pixabay
Oct. 25 (UPI) — Scientists have sequenced the oldest human DNA discovered in Britain and discovered two unique population groups that lived in Britain after the last ice age.
A sample discovered in Gough’s Cave in Somerset, England, from approximately 14,000 years ago, was compared to a sample from approximately 1,000 years later, which was discovered in Kendrick’s Cave, Wales.
“We knew from our previous work, including the study of Cheddar Man, that western hunter-gatherers were in Britain by around 10,500 years ago, but we didn’t know when they arrived in Britain, and whether this was the only population that was present,” said Selina Brace, a principal researcher at the Natural History Museum in Britain, who studies ancient DNA.
By studying the remains found in Gough’s Cave, researchers were able to determine that humans were present in Britain 300 years earlier than scientists had previously thought, meaning they were present before Britain began to warm after the last ice age.
Genetic studies of the two samples revealed that they came from two distinct genetic groups, meaning that at least two completely different populations of humans were living in Britain within a relatively short timeframe.
The artifacts discovered among the two populations suggest vastly different cultural practices.
“The evidence from the human remains found at Kendrick’s Cave suggests that the cave was used as a burial site by its occupiers,” said Silvia Bello, a researcher at the Natural History Museum who specializes in the evolution of human behavior.
In contrast, Bello said, “the evidence at Gough’s Cave points to a sophisticate culture of butchering and carving human remains.”
It was also revealed that these early inhabitants were using parts of animals believed to have already been extinct in Britain at the time including a spear tip made out of mammoth ivory and a baton made of reindeer antlers.
According to Chris Stringer, a research leader on human evolution at the Natural History Museum, “this raises several interesting questions: Did they bring these artifacts from somewhere colder? Or was Britain even more complicated and still had mammoth and reindeer surviving in the highlands?”
Almost 70% of animal populations wiped out since 1970, report reveals | Wildlife
Earth’s wildlife populations have plunged by an average of 69% in just under 50 years, according to a leading scientific assessment, as humans continue to clear forests, consume beyond the limits of the planet and pollute on an industrial scale.
From the open ocean to tropical rainforests, the abundance of birds, fish, amphibians and reptiles is in freefall, declining on average by more than two-thirds between 1970 and 2018, according to the WWF and Zoological Society of London’s (ZSL) biennial Living Planet Report. Two years ago, the figure stood at 68%, four years ago, it was at 60%.
Many scientists believe we are living through the sixth mass extinction – the largest loss of life on Earth since the time of the dinosaurs – and that it is being driven by humans. The report’s 89 authors are urging world leaders to reach an ambitious agreement at the Cop15 biodiversity summit in Canada this December and to slash carbon emissions to limit global heating to below 1.5C this decade to halt the rampant destruction of nature.
The Living Planet Index combines global analysis of 32,000 populations of 5,230 animal species to measure changes in the abundance of wildlife across continents and taxa, producing a graph akin to a stock index of life on Earth.
Latin America and the Caribbean region – including the Amazon – has seen the steepest decline in average wildlife population size, with a 94% drop in 48 years. Tanya Steele, chief executive at WWF-UK, said: “This report tells us that the worst declines are in the Latin America region, home to the world’s largest rainforest, the Amazon. Deforestation rates there are accelerating, stripping this unique ecosystem not just of trees but of the wildlife that depends on them and of the Amazon’s ability to act as one of our greatest allies in the fight against climate change.”
Africa had the second largest fall at 66%, followed by Asia and the Pacific with 55% and North America at 20%. Europe and Central Asia experienced an 18% fall. The total loss is akin to the human population of Europe, the Americas, Africa, Oceania and China disappearing, according to the report.
“Despite the science, the catastrophic projections, the impassioned speeches and promises, the burning forests, submerged countries, record temperatures and displaced millions, world leaders continue to sit back and watch our world burn in front of our eyes,” said Steele. “The climate and nature crises, their fates entwined, are not some faraway threat our grandchildren will solve with still-to-be-discovered technology.”
She added: “We need our new prime minister to show the UK is serious about helping people, nature and the economy to thrive, by ensuring every promise for our world is kept. Falling short will be neither forgotten nor forgiven.”
Leading nature charities have accused Liz Truss of putting the economy before nature protection and the environment, and are concerned rare animals and plants could lose their protections when her promise of a “bonfire” of EU red tape happens later this year.
The report points out that not all countries have the same starting points with nature decline and that the UK has only 50% of its biodiversity richness compared with historical levels, according to the biodiversity intactness index, making it one of the most nature-depleted countries in the world.
Land use change is still the most important driver of biodiversity loss across the planet, according to the report. Mike Barrett, executive director of science and conservation at WWF-UK, said: “At a global level, primarily the declines we are seeing are driven by the loss and fragmentation of habitat driven by the global agricultural system and its expansion into intact habitat converting it to produce food.”
The researchers underscore the increased difficulty animals are having moving through terrestrial landscapes as they are blocked by infrastructure and farmland. Only 37% of rivers longer than 1,000km (600 miles) remain free-flowing along their entire length, while just 10% of the world’s protected areas on land are connected.
Future declines are not inevitable, say the authors, who pinpoint the Himalayas, south-east Asia, the east coast of Australia, the Albertine Rift and Eastern Arc mountains in eastern Africa, and the Amazon basin among priority areas.
The IUCN is also developing a standard to measure the conservation potential of an animal, known as its green status, which will allow researchers to plot a path to recovery for some of the one million species threatened with extinction on Earth. The pink pigeon, burrowing bettong and Sumatran rhino were highlighted as species with good conservation potential in a study last year.
Robin Freeman, head of the indicators and assessments unit at ZSL, said it was clear that humanity is eroding the very foundations of life, and urgent action is needed. “In order to see any bending of the curve of biodiversity loss … it’s not just about conservation it’s about changing production and consumption – and the only way that we are going to be able to legislate or call for that is to have these clear measurable targets that ask for recovery of abundance, reduction of extinction risk and the ceasing of extinctions at Cop15 in December.”
Find more age of extinction coverage here, and follow biodiversity reporters Phoebe Weston and Patrick Greenfield on Twitter for all the latest news and features
Census of 140,000 Galaxies Reveals a Surprising Fact About Their Stars
How many of what kinds of stars live in other galaxies? It seems like a simple question, but it’s notoriously hard to pin down because astronomers have such a difficult time estimating stellar populations in remote galaxies.
Now a team of astronomers has completed a census of over 140,000 galaxies and found that distant galaxies tend to have heavier stars.
Stellar census
Even though astronomers lack a complete census of all the hundreds of billions of stars in the Milky Way galaxy, they’ve sampled enough of them to get a pretty good handle on the population.
We know, roughly, how many small dwarf stars there are, how many medium Sun-like ones there are, and how many giant ones there are.
But repeating this exercise for other galaxies is enormously difficult. Most galaxies are simply too far away to identify and measure individual stars within them.
We only see their brighter, heavier stars, and have to guess about the populations of smaller ones.
Typically, astronomers just assume that the demographics of a distant galaxy roughly match what we see in the Milky Way because on average galaxies shouldn’t be all that different from each other.
Recently, a team of astronomers used the COSMOS catalog to study 140,000 individual galaxies, developing techniques to estimate the population of stars in each one.
The research was conducted at the Cosmic Dawn Center (DAWN), an international basic research center for astronomy supported by the Danish National Research Foundation. DAWN is a collaboration between the Niels Bohr Institute at the University of Copenhagen and DTU Space at the Technical University of Denmark.
The future fate of heavier galaxies
“We’ve only been able to see the tip of the iceberg and known for a long time that expecting other galaxies to look like our own was not a particularly good assumption to make. However, no one has ever been able to prove that other galaxies form different populations of stars. This study has allowed us to do just that, which may open the door for a deeper understanding of galaxy formation and evolution,” says Associate Professor Charles Steinhardt, a co-author of the study.
The team found that on average more distant galaxies tended to have bigger stars than the Milky Way. On the other hand, nearby galaxies were relatively similar to our own.
“The mass of stars tells us astronomers a lot. If you change mass, you also change the number of supernovae and black holes that arise out of massive stars. As such, our result means that we’ll have to revise many of the things we once presumed, because distant galaxies look quite different from our own,” says Albert Sneppen, a graduate student at the Niels Bohr Institute and first author of the study.
This work has several important implications.
For one, astronomers can no longer assume a uniform population of stars when looking at distant galaxies, which represent the youngest galaxies to appear in the universe. It also forces us to rethink how galaxies evolve through billions of years.
“Now that we are better able to decode the mass of stars, we can see a new pattern; the least massive galaxies continue to form stars, while the more massive galaxies stop birthing new stars. This suggests a remarkably universal trend in the death of galaxies,” concludes Sneppen.
This article was originally published by Universe Today. Read the original article.
Globular cluster Messier 14 and its peculiar multiple stellar populations investigated by Hubble
Using the Hubble Space Telescope (HST), astronomers have observed the globular cluster Messier 14 and its peculiar multiple stellar populations. Results of the observational campaign, published January 7 on arXiv.org, deliver important insight into the nature of this cluster.
Globular clusters (GCs) are collections of tightly bound stars orbiting galaxies. Astronomers perceive them as natural laboratories enabling studies on the evolution of stars and galaxies. In particular, globular clusters could help researchers better understand the formation history and evolution of early type galaxies, as the origin of GCs seems to be closely linked to periods of intense star formation.
At a distance of about 30,300 light years away from the Earth, Messier 14 (or M14, also known as NGC 6402) is GC in our Milky Way galaxy, located near the Galactic plane. Although M14 is one of the most massive and luminous Galactic GCs, it has not been comprehensively studied yet, mainly due to its high reddening (approximately 0.6) and its proximity to the Galactic plane.
In order to change this, a team of astronomers led by Francesca D’Antona of Rome Observatory in Italy decided to conduct photometric observations of M14 using HST’s Ultraviolet and Visual Channel of the Wide Field Camera 3 (UVIS/WFC3) and the Wide Field Channel of the Advanced Camera for Surveys (WFC/ACS).
“We have presented multi-band photometry of the massive GC NGC 6402 based on multi-band HST observations collected as part of GO-16283 (PI.F.D’Antona),” the researchers wrote in the paper.
The observations allowed the team to obtain the chromosome map (ChM) of M14. It is a pseudo-two-color diagram that serves as an efficient tool to classify globular clusters and to characterize their multiple populations.
One of the most intriguing properties of multiple populations in M14 is a huge gap in the distribution of some light elements like oxygen or magnesium. Therefore, the authors of the study used ChM to investigate this peculiarity.
According to the paper, the chromosome map of M14 does not show stars with extreme chemical compositions as observed in some other known massive GCs. It was noted that the ChM lacks the group of stars with extreme anomalies (dubbed E stars).
The ChM shows that M14 contains a group of stars with higher metallicity—the so-called population 2G stars (dubbed 2GD)—on the red side of the diagram. In general, 2G stars showcase abundance patterns typical of gas processed at very high temperatures (between 30 and 100 million K) by proton capture reactions. These results indicate that M14 is a Type II cluster—an iron-complex cluster exhibiting a remarkably complex ChM.
The study also found that M14 does not host stellar populations with an extreme helium content and the researchers suppose that this cluster has undergone two stages of 2G star formation.
“The first one from matter strongly contaminated with p-processed elements and significantly rich in helium, the second one from matter—not necessarily sharing the same heavy p-processing of the first event—heavily diluted with pristine gas, so that both the helium content and the abundances of light elements remain either standard or close to standard,” the scientists concluded.
Messier 85’s complex globular cluster system explored by researchers
More information:
Francesca D’Antona et al, HST observations of the globular cluster NGC 6402 (M14) and its peculiar multiple populations. arXiv:2201.02546v1 [astro-ph.SR], arxiv.org/abs/2201.02546
Francesca D’Antona et al, HST observations of the globular cluster NGC 6402 (M14) and its peculiar multiple populations. arXiv:2201.02546v1 [astro-ph.SR], arxiv.org/abs/2201.02546
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Any COVID-19 variant ‘is severe’ for unvaccinated populations, doctor explains
The Omicron variant has pushed the U.S. to exceed 65 million total cases of coronavirus.
Though symptoms of the strain have been described as “mild” in comparison to previous variants, that mainly applies to those who are fully vaccinated and boosted. For those who are still unvaccinated or immunocompromised, it’s a different story at a population level.
“We have to remember: We’re a country that has over 35% of individuals who are not vaccinated,” Dr. Stella Safo, an NYC-based HIV primary care physician, said on Yahoo Finance Live (video above). “And any variant of COVID, unfortunately, in the unvaccinated is severe.”
Those who are unvaccinated are 20 times more likely to die and 17 times more likely to be hospitalized as a result of COVID-19, which is likely contributing to the massive surge in hospitalizations across the U.S.
Furthermore, given the amount of mutations with Omicron, natural immunity provided by previous infection is less protective than before.
“We shouldn’t underestimate COVID,” Safo said. “Every single time we’ve thought that we’re getting ahead in some way, COVID kind of forces us to respect it all over again. And one of the things that I think the COVID strategy requires of us is to be multifaceted.”
Boosters are also a factor: New data from Alberta, Canada, found that the “hospitalization rate among 3x-vaccinated 80+ year olds is lower than the hospitalization rate among unvaccinated 12-29-year-olds.”
‘Cannot afford to be cavalier’ with Omicron
As of January 15, 62.9% of the U.S. population is fully vaccinated, 74.8% have received one dose, and 37.8% have been boosted.
And because symptoms haven’t been as severe in those who are vaccinated and boosted, along with the politics involved, mask mandates and other public health restrictions that were initially seen at the beginning of the pandemic are not as viable.
As Safo stated, however, any variant that arises poses a serious health risk for both unvaccinated and immunocompromised individuals.
“There are people I work with, people I know, who have compromised immune systems who have gotten all three vaccines, whose immune systems are still compromised enough that if they got COVID, they’d be really sick,” Safo said. “Those individuals cannot afford to be cavalier about ‘Well, I’ll get COVID at some point and that’s it.’ Because they could get COVID and die.”
The idea of a fourth vaccine dose has been floated as a possible measure for those types of individuals. Israel has already started administering fourth doses to its most vulnerable citizens.
“I think there’s a real fear that many people have, still, of what this means for certain high-risk populations,” Safo said. “We really have to be sensitive to that, at a point where we can still control the spread through things like masking and really being mindful about what kind of things we have opened that are non-essential where people are getting infected currently.”
There’s also the possibility of individuals — vaccinated or not — developing long-term effects from COVID regardless of how mild their cases are. Long COVID symptoms can range from fatigue, “brain fog,” and heart palpitations to autoimmune conditions, according to the CDC.
Furthermore, Safo noted, the U.S. population “carries quite a bit” of chronic illness such as diabetes, hypertension, and renal disease that may be made worse by any infection.
“All those individuals are still at risk for some complications with COVID,” she said. “When we talk cavalierly about how everyone will get COVID, yes many people will get COVID, [but] not everyone will get COVID, even if they’re unvaccinated, and be OK.”
Adriana Belmonte is a reporter and editor covering politics and health care policy for Yahoo Finance. You can follow her on Twitter @adrianambells and reach her at adriana@yahoofinance.com.
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Some People in Greenland Metabolize Sugars Differently
For millennia, populations in Greenland enjoyed a relatively sugar-free diet. Without the need to rapidly process certain carbohydrates, many lost the function of a key sucrose-processing enzyme.
To learn what this loss means for the health of today’s populations, a team of researchers led by scientists from the University of Copenhagen analyzed the health of thousands of Greenlandic people.
The gene at the center of the study produces the enzyme sucrase-isomaltase. At some point in Greenland’s history it mutated to the extent it no longer works. Just over a third of its descendents now carry at least one of these broken variants.
For the rest of us, working versions of the enzyme sit in our intestinal wall, where they digest dietary carbohydrates such as sucrose (the kind of sugar you might sprinkle into your coffee) and isomaltose (a component of caramelized glucose).
Based on the results of past studies on children, this sugar-absorbing enzyme is necessary for good health. Without it, the consumption of any significant amount of sugary food results in diarrhea, gut irritability, and vomiting. Whether this applies to adults, however, remains an open question.
An assessment of blood chemistry, diet, and history of diabetes was carried out on more than 6,000 Greenlandic volunteers, along with a study of their genes. All were over 18 years of age.
Surprisingly, where children reportedly suffered severe reactions to sugar consumption to the point it could affect their development, adults more or less thrived.
The results associated possession of two copies of the defunct gene with a lower body mass index and reduced percentages of fat, as well as a healthy lipid profile.
A group within the study population also showed intriguing levels of a chemical called acetate. Circulation of this short-chain fatty acid has been linked with lower appetites, further indicating the loss of this key enzyme might have certain benefits in a world where overindulgence in high-energy foods is hard to avoid.
The researchers suspect the surplus of simple carbohydrates in the gut could favor microflora that transform it into acetate, turning it from a potential irritant into a tool for a healthier diet.
Experimental results based on mice engineered to resist absorption of sucrose also showed they stored less fat when fed energy-rich diets.
Whether this knowledge might inform future generations of fat-fighting therapies is hard to say. Further studies are needed to fully explore the consequences of inhibiting otherwise functional forms of sucrase-isomaltase in the guts of individuals who might need a helping hand in managing their sugar digestion.
This research was published in Gastroenterology.
Staggering Data on How Much Whales Actually Eat Just Solved The ‘Krill Paradox’
Scientists have found that large whales eat at least three times as much as previously thought, a discovery which highlights their importance in keeping the oceans healthy.
The study, published Wednesday in the peer-reviewed journal Nature, provides clues as to why wiping out millions of the largest whales on the planet was so devastating to marine environments.
Reestablishing the whale population could do wonders for marine environments and might even help replenish dwindling fish populations, two scientists told Insider.
The krill paradox
From 1900 to 1970, industrial whaling wiped out about 1.5 million larges whales around Antarctica.
“The largest whale species on the planet were systematically hunted, which reduced abundances probably greater than 70 percent in many cases,” Nicholas Pyenson, an author on the study and curator of fossil marine mammals at the Smithsonian Institution, told Insider.
“99 percent of the blue whales that were alive in 1900 were gone by 1960,” he said.
Scientists in the 70s had assumed that without the whales to prey on them, populations of krill and fish would explode and other predators would thrive as they filled the gap in the food chain.
But that’s not what happened. The ecosystem never bounced back.
“In actuality, there was an incredible decline [of krill] over the following 50 years – and it’s still happening today,” said Matthew Savoca, the lead author on the study and a postdoctoral scholar at Stanford’s Hopkins Marine Station.
“The steepest declines in krill biomass have been seen in areas where the most whales were killed,” he told Insider.
The “krill paradox” had left scientists puzzled.
Whales turn over a lot more food than previously thought
Up until recently, it was extremely difficult to get a sense of how large whales fed. They can’t be kept in captivity and they feed deep under the surface of the water.
The scientists running the study developed sensors that can detect fish and krill as the whale eats them.
These sensors, which are stuck on the whales using suction cups as seen in the video below, were used to track 321 baleen whales from seven different species in the Southern Ocean, which surrounds Antarctica.
Using this tech, the scientists found the whales eat three or more times than was previously thought.
That means that pre-whaling populations in the Southern Ocean alone would have eaten about 400 million metric tons of krill per year, far more than had been assumed.
That’s also twice as much the total amount of krill left in Antarctica today.
(Elliott Hazen under NOAA/NMFS permit 16111)
Above: Researchers approach a blue whale to attach a suction-cup tag.
It means whales produce a lot more of their iron-rich poop, the fact which explains the severity of environmental damage when they were killed.
“We believe these whales are acting as key nutrient recyclers in this ecosystem,” said Savoca.
As the whales feed and defecate, they redistribute the iron towards the surface of the ocean. That makes the iron available for phytoplankton, small algae which can’t grow without the nutrient.
These in turn are eaten by krill, which are eaten by the whales.
Without the whales, a large proportion of this iron falls towards the bottom of the ocean, effectively leaving the ecosystem.
Because the whales seem to be such a pivotal actor in the ecosystem, reestablishing the whale population in the Southern Ocean and in other oceans would be beneficial to the marine environments, said Pyenson and Savoca.
“You’d see more krill, more whales. You would probably also see, as a consequence of a healthier ecosystem, is greater fish yields, penguin populations might rebound, there are all kinds of downstream consequences,” said Pyenson.
Whaling today “doesn’t have really that much of an impact on the world’s whale populations,” he said, because its scale is very small compared to the past.
But far more whales – hundreds of thousands – are killed accidentally by humans, either by getting hit by ships or by getting stuck in fishing gear, Pyenson said.
This article was originally published by Business Insider.
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FDA Authorizes Booster Dose of Pfizer-BioNTech COVID-19 Vaccine for Certain Populations
- For Immediate Release:
Today, the U.S. Food and Drug Administration amended the emergency use authorization (EUA) for the Pfizer-BioNTech COVID-19 Vaccine to allow for use of a single booster dose, to be administered at least six months after completion of the primary series in:
- individuals 65 years of age and older;
- individuals 18 through 64 years of age at high risk of severe COVID-19; and
- individuals 18 through 64 years of age whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19.
Today’s authorization applies only to the Pfizer-BioNTech COVID-19 Vaccine.
“Today’s action demonstrates that science and the currently available data continue to guide the FDA’s decision-making for COVID-19 vaccines during this pandemic. After considering the totality of the available scientific evidence and the deliberations of our advisory committee of independent, external experts, the FDA amended the EUA for the Pfizer-BioNTech COVID-19 Vaccine to allow for a booster dose in certain populations such as health care workers, teachers and day care staff, grocery workers and those in homeless shelters or prisons, among others,” said Acting FDA Commissioner Janet Woodcock, M.D. “This pandemic is dynamic and evolving, with new data about vaccine safety and effectiveness becoming available every day. As we learn more about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed.”
The Process for Assessing the Available Data
Comirnaty (COVID-19 Vaccine, mRNA), was approved by the FDA on Aug. 23, for the prevention of COVID-19 caused by SARS-CoV-2 in individuals 16 years of age and older. On Aug. 25, 2021, the FDA received a supplement from Pfizer Inc. to their biologics license application for Comirnaty seeking approval of a single booster dose to be administered approximately six months after completion of the primary vaccination series for individuals 16 years of age and older.
As part of the FDA’s commitment to transparency, the agency convened a public meeting of its Vaccines and Related Biological Products Advisory Committee (VRBPAC) on Sept. 17 to solicit input from independent scientific and public health experts on the data submitted in the application. During the meeting, the vaccine manufacturer presented information and data in support of its application. The FDA also presented its analysis of clinical trial data submitted by the vaccine manufacturer. Additionally, the public was also given an opportunity to provide comment; and FDA invited international and U.S. agencies and external groups, including representatives from the Israeli Ministry of Health, the University of Bristol, U.K. and the Centers for Disease Control and Prevention, to present recent data on the use of vaccine boosters, epidemiology of COVID-19, and real-world evidence on vaccine effectiveness.
The FDA considered the data that the vaccine manufacturer submitted, information presented at the VRBPAC meeting, and the committee’s discussion, and has determined that based on the totality of the available scientific evidence, a booster dose of Pfizer-BioNTech COVID-19 Vaccine may be effective in preventing COVID-19 and that the known and potential benefits of a booster dose outweigh the known and potential risks in the populations that the FDA is authorizing for use. The booster dose is authorized for administration to these individuals at least six months following completion of their primary series and may be given at any point after that time.
It’s important to note that the FDA-authorized Pfizer-BioNTech COVID-19 Vaccine is the same formulation as the FDA-approved Comirnaty and the vaccines may be used interchangeably.
“We’re grateful for the advice of the doctors, scientists, and leading vaccine experts on our advisory committee and the important role they have played in ensuring transparent discussions about COVID-19 vaccines. We appreciate the robust discussion, including the vote regarding individuals over 65 years of age and individuals at high risk for severe disease, as well as the committee’s views regarding the use of a booster dose for those with institutional or occupational exposure to SARS-CoV-2,” said Peter Marks, M.D., Ph.D., director of FDA’s Center for Biologics Evaluation and Research. “The FDA considered the committee’s input and conducted its own thorough review of the submitted data to reach today’s decision. We will continue to analyze data submitted to the FDA pertaining to the use of booster doses of COVID-19 vaccines and we will make further decisions as appropriate based on the data.”
Data Supporting Authorization for Emergency Use
To support the authorization for emergency use of a single booster dose, the FDA analyzed safety and immune response data from a subset of participants from the original clinical trial of the Pfizer-BioNTech COVID-19 Vaccine. In addition, consideration was given to real-world data on the vaccine’s efficacy over a sustained period of time provided by both U.S. and international sources, including the CDC, the UK and Israel. The immune responses of approximately 200 participants 18 through 55 years of age who received a single booster dose approximately six months after their second dose were assessed. The antibody response against SARS-CoV-2 virus one month after a booster dose of the vaccine compared to the response one month after the two-dose primary series in the same individuals demonstrated a booster response.
Additional analysis conducted by the manufacturer, as requested by the FDA, compared the rates of COVID-19 accrued during the current Delta variant surge among original clinical trial participants who completed the primary two-dose vaccination series early in the clinical trial to those who completed a two-dose series later in the study. The analysis submitted by the company showed that during the study period of July and August 2021, the incidence of COVID-19 was higher among the participants who completed their primary vaccine series earlier, compared to participants who completed it later. The FDA determined that the rate of breakthrough COVID-19 reported during this time period translates to a modest decrease in the efficacy of the vaccine among those vaccinated earlier.
Safety was evaluated in 306 participants 18 through 55 years of age and 12 participants 65 years of age and older who were followed for an average of over two months. The most commonly reported side effects by the clinical trial participants who received the booster dose of the vaccine were pain, redness and swelling at the injection site, as well as fatigue, headache, muscle or joint pain and chills. Of note, swollen lymph nodes in the underarm were observed more frequently following the booster dose than after the primary two-dose series.
Since Dec. 11, 2020, the Pfizer-BioNTech COVID-19 Vaccine has been available under EUA for individuals 16 years of age and older. The authorization was expanded on May 20, 2021 to include those 12 through 15 years of age, and again on Aug. 12, 2021 to include the use of a third dose of a three-dose primary series in certain immunocompromised individuals 12 years of age and older. EUAs can be used by the FDA during public health emergencies to provide access to medical products that may be effective in preventing, diagnosing, or treating a disease, provided that the FDA determines that the known and potential benefits of a product, when used to prevent, diagnose, or treat the disease, outweigh the known and potential risks of the product.
The amendment to the EUA to include a single booster dose was granted to Pfizer Inc.
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Model reveals surprising disconnect between physical characteristics and genetic ancestry in certain populations
A new study by Stanford University biologists finds an explanation for the idea that physical characteristics such as skin pigmentation are “only skin deep.” Using genetic modeling, the team has found that when two populations with distinct traits combine over generations, traits of individuals within the resulting “admixed” population come to reveal very little about individuals’ ancestry. Their findings were published March 27 in a special edition of the American Journal of Physical Anthropology on race and racism.
“When two founding groups first come together, a visible physical trait that differed between those founders initially carries information about the genetic ancestry of admixed individuals,” says Jaehee Kim, a postdoctoral research fellow in biology at Stanford and first author of the study. “But this study shows that after enough time has passed, that’s no longer true, and you can no longer identify a person’s genetic ancestry based only on such traits.”
A diminishing correlation
Working with Stanford biology professor Noah Rosenberg and others, Kim built a mathematical model to better understand genetic admixture—the process by which two populations that have long been separated come together and create a third admixed population with ancestral roots in both sources. They specifically studied how the relationship between physical traits and genetic admixture level changes over time.
The researchers considered several scenarios. In one, individuals within the admixed population mated randomly. In others, they were more likely to seek out partners with similar genetic admixture levels or who had similar levels of a trait, in a process known as assortative mating.
The study found that over time, traits that might have initially been indicative of an individual’s genetic ancestry ultimately no longer carried that information. While this decoupling of ancestry and traits occurred more slowly if mating was assortative rather than random, decoupling still happened in all scenarios.
“In the model, if assortative mating depends on a genetically inherited trait, a correlation between the trait and genetic ancestry would last longer than if mating had occurred randomly, but the correlation would still disassociate eventually,” said Rosenberg, senior author of the paper, who holds the Stanford Professorship in Population Genetics and Society in the School of Humanities and Sciences.
The team’s research was inspired in part by a study conducted by a different team in Brazil, a country with much genetic admixture in its history. After sampling individuals and studying their genomes, the biologists from the 2003 study hypothesized that decoupling occurred between physical traits and genetic admixture and claimed that over time traits such as skin pigmentation revealed little about the fraction of a person’s ancestors originating from European, African or Native American origins. The Stanford team found that their model largely supported this hypothesis.
Only skin deep
To understand the decoupling, the researchers say, consider a trait such as skin pigmentation that is due in part to variations among a series of genes. If a person happens to receive most of their genetic ancestry from one population but the key genetic variants that determine their skin pigmentation from another, their skin pigmentation may appear to be a “mismatch” to their genetic ancestry. The reshuffling of genetic variants that occurs in every generation increases the probability of such mismatches.
The researchers recognize that there are limitations to their modeling approach. The model didn’t consider environmental conditions that also play a role in trait development. A person’s height, for example, has some genetic basis, but also depends on factors like nutrition. The model also focused only on scenarios in which the initial admixture happened all at once, and didn’t explore the role of new members of the source populations entering the admixed population over time. In the future, Rosenberg plans to add some of these features into the initial model.
According to Kim, the new findings have important implications for understanding the social meaning of physical traits.
“When societies attach social meaning to a trait like skin pigmentation, the model suggests that after admixture has been ongoing for enough time, that trait is not going to be telling us much about genetic ancestry—or about other traits that are based in genetics,” she said.
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More information:
Jaehee Kim et al, Skin deep: The decoupling of genetic admixture levels from phenotypes that differed between source populations, American Journal of Physical Anthropology (2021). DOI: 10.1002/ajpa.24261
Jaehee Kim et al, Skin deep: The decoupling of genetic admixture levels from phenotypes that differed between source populations, American Journal of Physical Anthropology (2021). DOI: 10.1002/ajpa.24261
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Stanford University
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Model reveals surprising disconnect between physical characteristics and genetic ancestry in certain populations (2021, April 5)
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