Scientists link star-shredding event to origins of universe's highest-energy particles

NEW YORK UNIVERSITY

 VIDEO: AS THE STAR APPROACHES THE BLACK HOLE, THE ENORMOUS TIDAL FORCES STRETCH IT MORE AND MORE UNTIL IT IS FINALLY SHRED. HALF OF THE STELLAR DEBRIS IS FLUNG BACK INTO... view more 

CREDIT: DESY, SCIENCE COMMUNICATION LAB

A team of scientists has detected the presence of a high-energy neutrino--a particularly elusive particle--in the wake of a star's destruction as it is consumed by a black hole. This discovery, reported in the journal Nature Astronomy, sheds new light on the origins of Ultrahigh Energy Cosmic Rays--the highest energy particles in the Universe.

The work, which included researchers from more than two dozen institutions, including New York University and Germany's DESY research center, focused on neutrinos--subatomic particles that are produced on Earth only in powerful accelerators.

Neutrinos--as well as the process of their creation--are hard to detect, making their discovery, along with that of Ultrahigh Energy Cosmic Rays (UHECRs), noteworthy.

"The origin of cosmic high-energy neutrinos is unknown, primarily because they are notoriously hard to pin down," explains Sjoert van Velzen, one of the paper's lead authors and a postdoctoral fellow in NYU's Department of Physics at the time of the discovery. "This result would be only the second time high-energy neutrinos have been traced back to their source."

Previous research by van Velzen, now at the Netherlands' Leiden University, and NYU physicist Glennys Farrar, a co-author of the new Nature Astronomy paper, found some of the earliest evidence of black holes destroying stars in what are now known as Tidal Disruption Events (TDEs). These findings set the stage for determining if TDEs could be responsible for producing UHECRs.

The research reported in Nature Astronomy offered support for this conclusion.

Previously, the IceCube Neutrino Observatory, a National Science Foundation-backed detector located in the South Pole, reported the detection of a neutrino, whose path was later traced by the Zwicky Transient Facility at Caltech's Palomar Observatory.

Specifically, its measurements showed a spatial coincidence of a high-energy neutrino and light emitted after a TDE--a star consumed by a black hole.

"This suggests these star shredding events are powerful enough to accelerate high-energy particles," van Velzen explains.

"Discovering neutrinos associated with TDEs is a breakthrough in understanding the origin of the high-energy astrophysical neutrinos identified by the IceCube detector at the South Pole whose sources have so far been elusive," adds Farrar, who proposed in a 2009 paper that UHECRs could be accelerated in TDEs. "The neutrino-TDE coincidence also sheds light on a decades old problem: the origin of Ultrahigh Energy Cosmic Rays."

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The research was supported by grants from the National Science Foundation (CAREER grant 1454816, AAG grant 1616566, PIRE Grant 1545949, NSF grant AST-1518052)

DOI: 10.1038/s41550-020-01295-8

CAPTION

After the supermassive black hole tore the star apart, roughly half of the star debris was flung back out into space, while the remainder formed a glowing accretion disc around the black hole. The system shone brightly across many wavelengths and is thought to have produced energetic, jet-like outflows perpendicular to the accretion disc. A central, powerful engine near the accretion disc spewed out these fast subatomic particles.

CREDIT

DESY, Science Communication Lab

CAPTION

A view of the accretion disc around the supermassive black hole, with jet-like structures flowing away from the disc. The extreme mass of the black hole bends spacetime, allowing the far side of the accretion disc to be seen as an image above and below the black hole.

CREDIT

DESY, Science Communication Lab

Allergy season starts earlier each year due to climate change and pollen transport

Scientists in Munich study how pollen from far distances -- sometimes hundreds of kilometers away -- affects the length of allergy seasons in Germany

FRONTIERS

Research News

 

IMAGE: GRASS POLLEN GRAINS UNDER LIGHT MICROSCOPE view more 

CREDIT: A. MENZEL AND Y. YUAN, TECHNICAL UNIVERSITY OF MUNICH

Allergy sufferers are no strangers to problems with pollen. But now - due to climate change - the pollen season is lasting longer and starting earlier than ever before, meaning more days of itchy eyes and runny noses. Warmer temperatures cause flowers to bloom earlier, while higher CO2 levels cause more pollen to be produced.

The effects of climate change on the pollen season have been studied at-length, and according to some scientists, has grown by as much as 20 days in the past 30 years, at least in the US and Canada. But one important element is often overlooked - "Pollen is meant to fly," says Dr Annette Menzel, Professor of ecoclimatology at the Technical University of Munich. "Transport phenomena have to be taken into account."

Along with her colleagues, she studied the transport of pollen in Bavaria, Germany, in order to better understand how the pollen season has changed over time. "The transport of pollen has important implications for the length, timing, and severity of the allergenic pollen season," says Dr Ye Yuan, a coauthor on the study.

Menzel and her team focused on Bavaria - a state in southeast Germany - and used six pollen monitoring stations scattered around the region to analyze data. Their results were recently published in Frontiers in Allergy. They found that certain species of pollen, such as from hazel shrubs and alder trees, advanced the start of their seasons by up to 2 days per year, over a period of 30 years (between 1987 and 2017). Other species, which tend to bloom later in the year, such as birch and ash trees, moved their seasons 0.5 days earlier on average each year, across that same time period.

Pollen can travel hundreds of kilometers and, with changing weather patterns and altered species distributions, it's possible that people are becoming exposed to "new" pollen species - meaning pollen that our bodies are unaccustomed to encountering each year.

While it can sometimes be difficult to differentiate between local and transported pollen, the researchers focused on pre-season transports. So, for example, if pollen from birch trees was present at the monitoring station, but local birch trees would not flower for at least another 10 days, that pollen was considered to be transported from far away.

"We were surprised that pre-season pollen transport is a quite common phenomenon being observed in two-thirds of the cases," says Menzel. As for why it's important to understand how much pollen is from far away, Yuan says that: "Especially for light-weight allergenic [pollen], long distance transport could seriously influence local human health."

By examining another element besides simple pollen concentration, scientists can delve deeper into how exactly the pollen season is being affected by climate change. For example, Menzel says that the pollen season may be even longer than estimated based on flowering observations by "taking into account pollen transport, as it has been done in our current study."

While the Munich study did not track how far pollen was transported, and only differentiated between local and long-range transport (meaning pollen coming from outside Bavaria), it provides a crucial key in our understanding of annual pollen patterns. Yuan says that future studies should account for "climate change scenarios [and] land use/land cover changes." He also adds that citizen scientists may be able to contribute to pollen studies, who can help collect local observations and contribute to data collection.

It doesn't look like the pollen season will shorten any time soon, but more research on the subject can provide a better understanding of global patterns and changes so that we can better address these issues in the future.

CAPTION

Trap for measuring abundances of windborne pollen

CREDIT

A. Menzel and Y. Yuan, Technical University of Munich

The Tubes - Hoods From Outer Space 

(full album)

•Sep 26, 2016
The Tubes - Hoods From Outer Space

 1. Hoods From Outer Space 0:00​

 2. I Know You 4:08​ 

3. Say What You Want 8:00​

4. Around The World 12:10​ 

5. Genius Of America 16:34​ 

6. Who Names The Hurricanes 20:45​ 

7. It's Too Late 25:34​ 

8. How Can You Live With Yourself 28:25​

 9. I Never Saw It Comin" 33:39​ 

10. Arms Of The Enemy 36:58

​ 11. Fishhouse 41:34​ 

12. Big Brother"s Still Watching 46:12​ 

13. Fastest Gun Alive 51:06​ 

14. After All You Said 56:08

 WHITE JUNKIES

Study shows opioid use among US patients with knee osteoarthritis costs 14 billion dollars in societal costs

WILEY

Research News

 

Although guidelines do not recommend use of opioids to manage pain for individuals with knee osteoarthritis, a recent study published early online in Arthritis Care & Research, an official journal of the American College of Rheumatology and the Association of Rheumatology Professionals, estimates that 858,000 Americans use opioids such as tramadol and oxycodone for their knee pain, equating to $14 billion in lifetime opioid-related societal costs, or nearly $0.5 billion annually.

A team led by Elena Losina, PhD, Robert W. Lovett Professor of Orthopedic Surgery, of Brigham and Women's Hospital, used a computer simulation to estimate the annual and lifetime contribution of opioids to knee osteoarthritis-related costs. The researchers show the direct medical cost of knee osteoarthritis treatment including opioids totals $7.45 billion or 53 percent of the total lifetime costs. The remaining 47 percent of lifetime costs to society is used to pay for lost productivity at work, criminal justice expenses due to opioid use disorders among patients with knee osteoarthritis and cost associated with diversion activities related to illicit use by others.

For an individual patient who used opioids to treat their knee osteoarthritis, the lifetime opioid-related cost was estimated at $13,770. "Given larger number of patients with knee osteoarthritis using opioids, our results provide additional evidence of the substantial economic burden of opioid use for knee osteoarthritis pain management and the potential savings from preventing opioid use," said Dr. Losina.

The results reveal a substantial economic burden of opioid use among patients with knee osteoarthritis, and they indicate that substantial savings can result from following current guidelines recommending against such use.

"The most important part of our study is that we estimated that almost half of the total societal cost of opioid use in persons with symptomatic knee osteoarthritis is used to pay for lost work productivity and criminal justice and other consequences of the diversion of prescribed opiates to unlawful use," concludes Dr. Losina. "These data offer new evidence of the magnitude of the societal burden generated by opioid use and misuse and could be used to educate health care providers and health policy decision makers on the best alternatives to opiate use."

###

Additional Information

NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact:

Dawn Peters +1 781-388-8408 (US)
newsroom@wiley.com

Follow us on Twitter @WileyNews

Full Citation: "Societal cost of opioid use in symptomatic knee osteoarthritis patients in the United States." Jamie L. Huizinga, Elizabeth E. Stanley, James K. Sullivan, Shuang Song, David J. Hunter, A. David Paltiel, Tuhina Neogi, Robert R. Edwards, Jeffrey N. Katz, and Elena Losina. Arthritis Care & Research; Published Online: February 25, 2021 (DOI: 10.1002/acr.24581).

URL Upon Publication: http://doi.wiley.com/10.1002/acr.24581

Author Contact: Haley Bridger, of the Brigham and Women's Media Relations Office, at hbridger@bwh.harvard.edu or +1 617-525-6383.

About the Journal

Arthritis Care & Research is an official journal of the American College of Rheumatology (ACR) and the Association of Rheumatology Professionals (ARP), a division of the College. Arthritis Care & Research is a peer-reviewed journal that publishes both original research and review articles that promote excellence in the clinical practice of rheumatology. Relevant to the care of individuals with arthritis and related disorders, major topics are evidence-based practice studies, clinical problems, practice guidelines, health care economics, health care policy, educational, social, and public health issues, and future trends in rheumatology practice. The journal is published by >

Wiley on behalf of the ACR. For more information, please visit the journal home page at http://wileyonlinelibrary.com/journal/acr.

On the line: Watching nanoparticles get in shape

New method could advance next-generation applications in medicine, cosmetics, and petroleum recovery

DOE/LAWRENCE BERKELEY NATIONAL LABORATORY

Research News

VIDEO: IMAGING OF THE SAME SPOT SHOWS THAT CRACKS EVENTUALLY SELF-HEAL, AN IMPORTANT TRADEMARK THAT MAINTAINS THE INTEGRITY OF STRUCTURED LIQUIDS. REAL-TIME VIDEO OF 70 NM NANOPARTICLES (RED) AND 500 NANOMETER... view more 

CREDIT: PAUL ASHBY AND TOM RUSSELL/BERKELEY LAB AND SCIENCE ADVANCES

Liquid structures - liquid droplets that maintain a specific shape - are useful for a variety of applications, from food processing to cosmetics, medicine, and even petroleum extraction, but researchers have yet to tap into these exciting new materials' full potential because not much is known about how they form.

Now, a research team led by Berkeley Lab has captured real-time high-resolution videos of liquid structures taking shape as nanoparticle surfactants (NPSs) - soap-like particles just billionths of a meter in size - jam tightly together, side by side, to form a solid-like layer at the interface between oil and water.

Their findings, recently featured on the cover of Science Advances , could help researchers better optimize liquid structures to advance new biomedical applications such as reconfigurable microfluidics for drug discovery and all-liquid robotics for targeted cancer drug delivery, among others.

In experiments led by co-author Paul Ashby , a staff scientist in Berkeley Lab's Molecular Foundry and Materials Sciences Division, and Yu Chai, a former postdoctoral researcher in the Ashby group who is now an assistant professor at The City University of Hong Kong, the researchers used a special imaging technique called atomic force microscopy (AFM) to take the first-ever real-time movies of the NPSs crowding together and getting jammed at the oil-water interface, a critical step in locking a liquid into a specific shape.

The researchers' movies unveiled a portrait of the NPS interface with unprecedented detail, including the size of each NPS, whether the interface was composed of one or multiple layers, and how much time elapsed, down to the second, for each NPS to attach to and settle into the interface.

The spectacular AFM images also showed the angle at which an NPS "sits" at the interface - an unexpected result. "We were surprised by how rough the interfaces are," Ashby said. "We had always drawn illustrations of a uniform interface with nanoparticles attached at the same contact angle - but in our current study, we found there is actually a lot of variation."

Most nanoscale imaging tools can only investigate immobile samples that are either dry or frozen. Over the past couple of decades, Ashby has focused his research on developing unique AFM capabilities that allow the user to control the probe tip so it gently interacts with fast-moving samples, such as the NPSs of the current study, without touching the underlying liquid - a challenging feat.

"Imaging a liquid structure at the nanoscale, and watching the nanoparticles move around in liquid in real time using an AFM probe - that wouldn't be possible without Paul's extensive expertise," said co-author Thomas Russell , a visiting faculty scientist and professor of polymer science and engineering from the University of Massachusetts who leads the Adaptive Interfacial Assemblies Towards Structuring Liquids program in Berkeley Lab's Materials Sciences Division. "These kinds of capabilities aren't available anywhere else except at the Molecular Foundry."

The researchers next plan to study the effect of self-propelling particles in NPS liquid structures.

###

Ashby and Russell co-led the study. Researchers from Berkeley Lab; UC Berkeley; The City University of Hong Kong; Hong Kong Polytechnic University; Soochow University and Beijing University of Chemical Technology, China; and Tohoku University, Japan, contributed to the work.

The Molecular Foundry is a DOE Office of Science user facility at Berkeley Lab.

This work was supported by the U.S. Department of Energy Office of Science.

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 14 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab's facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy's Office of Science.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

Conservation paradox - the pros and cons of recreational hunting

Recreational hunting -- especially hunting of charismatic species for their trophies -- raises ethical and moral concerns

FLINDERS UNIVERSITY

Research News

 

IMAGE: LIONS IN THE WILD view more 

CREDIT: ASSOCIATE PROFESSOR ENRICO DI MININ, UNIVERSITY OF HELSINKI

Recreational hunting -- especially hunting of charismatic species for their trophies --raises ethical and moral concerns. Yet recreational hunting is frequently suggested as a way to conserve nature and support local people's livelihoods.

In a new article published in the journal One Earth, scientists from the University of Helsinki in Finland and Flinders University in Australia have reviewed more than 1,000 studies on recreational hunting -- the first such attempt to summarize the scientific literature examining the biodiversity and social effects of recreational hunting globally.

Co-lead author University of Helsinki Associate Professor Enrico Di Minin says while it might seem counterintuitive, there is evidence to suggest some recreational hunting can deliver environmental and social benefits.

University of Helsinki colleague and co-lead author Dr Hayley Clements says more analysis is needed to understand how and why recreational hunting can work for good, and those areas where it can be detrimental.

Flinders University Professor Corey Bradshaw says it's a paradox that goes to the heart of the pros and cons of recreational hunting.

"We determined the geographic spread and diversity of species hunted around the globe, and investigated and summarized the main topics surrounding recreational hunting to consider both the positive and negative implications of recreational hunting for nature conservation and the livelihoods and well-being of people" says Professor Bradshaw, who leads Flinders' Global Ecology Lab.

"On the one hand, recreational hunting can reduce the number of individual animals in a population, whereas on the other, diverting land from agricultural or other types of development to priority hunting areas can in fact benefit entire ecosystems", he says.

Hunting research has focused mainly on the behaviour and population dynamics of large mammals in North America, Europe and Africa.

Dr Clements says evidence is still lacking, however, to answer the pressing questions of why hunting contributes to sustainable conservation of biodiversity in some places and not others.

"Two-thirds of the hunting research is focussed on mammals. Red deer, white-tailed deer, wild boar, moose and lion are the most well-studied. Of these species, only the lion is of conservation concern, with many recommendations on how hunting can be made sustainable through quotas or seasonal limits", says Dr Clements.

"Far less research has tried to examine the broader impacts of hunting on ecosystem integrity and function, and how it affects the livelihoods of local people, or to document local people's perceptions about hunting", she continues.

For example, approximately 1,394,000 km2 of land is dedicated for trophy hunting in sub-Saharan Africa, yet there is little research on how effective these areas are in conserving ecosystems, and how local communities benefit from hunting.

Associate Professor Di Minin, who leads the Helsinki Lab of Interdisciplinary Conservation Science contends future research should focus on the contribution of recreational hunting towards meeting both biodiversity and social objectives.

"We have outlined a research agenda to assess the role of recreational hunting in diverse social-ecological systems, and to consider local people's values and needs.

The need for such evidence is urgent given declining numbers of recreational hunters in some regions and increasing opposition to trophy hunting in others", says Associate Professor Di Minin.

"We should also expand research beyond charismatic and common species to assess the impact of recreational hunting on threatened and less charismatic species", he concludes

CAPTION

Zebra in the wild

CREDIT

Associate Professor Enrico Di Minin, University Of Helsinki

Article reference:

Di Minin, Enrico; Clements, Hayley; Correia, Ricardo; Cortés-Capano, Gonzalo; Hausmann, Anna; Haukka, Anna; Kulkarni, Ritwik; Bradshaw, Corey J. A. Consequences of recreational hunting for biodiversity conservation and livelihoods. One Earth doi: 10.1016/j.oneear.2021.01.014.

A-maze-ing pheasants have two ways of navigating

UNIVERSITY OF EXETER

Research News

 

IMAGE: A MAZE USED IN THE STUDY (HERE WITH ALL DOORS/WALLS OPEN). view more 

CREDIT: PIP LAKER

Pheasants fall into two groups in terms of how they find their way around - and the different types prefer slightly different habitats, new research shows.

University of Exeter scientists tested whether individual pheasants used landmarks (allocentric) or their own position (egocentric) to learn the way through a maze.

The captive-bred pheasants were later released into the wild, and their choice of habitat was observed.

All pheasants favoured woodland, but allocentric navigators spent more time out in the open, where their landmark-based style is more useful.

"Humans tend to use both of these navigational tactics and quite frequently combine them, but when animals are tested, they often seem to rely more on one or the other," said Dr Christine Beardsworth.

"It is assumed that species favour whichever strategy suits their habitat, rather than using habitats which suit their strategy.

"Pheasants generally favour woodland, where an allocentric strategy is difficult because there are lots of trees close together, so it is hard to pick out landmarks.

"So, we might expect most pheasants to use an egocentric strategy - turning left, turning right or moving forward based on their own position and previous movements.

"However, in our study about half of pheasants reared in identical conditions used an allocentric strategy, while the other half used an egocentric or mixed strategy."

In the experiments, 20 pheasants first learned how to navigate through a simple maze, then faced a rotated version.

By altering the orientation of the maze but keeping the placement of "landmarks" the same, including the position of a human observer, the scientists were able to establish the preferred navigation strategy of each pheasant.

The discovery of individual variation suggest pheasants are either born with an "inherent cognitive bias", or develop one early in life.

Resulting differences in habitat selection may indicate that these biases help them to navigate more effectively in particular environments, perhaps outperforming other pheasants in relocating resources. However, it is not yet clear whether this is the case.

CAPTION

A juvenile pheasant

CREDIT

Pip Laker

The research team included the Hebrew University of Jerusalem and Tel-Aviv University.

The work was funded by an ERC consolidators grant awarded to Dr Joah Madden.

The paper, published in the journal Ecology Letters, is entitled: "Is habitat selection in the wild shaped by individual-level cognitive biases in orientation strategy?"

DR. Simone Gold Arrested for Role in Capitol Insurrection

— Physician faces charges for entering restricted grounds, disorderly conduct

by Amanda D'Ambrosio, Staff Writer, MedPage Today




Simone Gold, MD, JD, founder of the notorious pro-hydroxychloroquine, anti-vaccine group America's Frontline Doctors, was arrested Sunday for participating in storming the U.S. Capitol earlier this month, according to the Department of Justice.

Following Gold's confirmation that she entered the Capitol building during the riot on Jan. 6, DOJ officials arrested her in California on Sunday. Gold faces charges of entering a restricted building and for violent entry and disorderly conduct.

Department representatives did not return a query as of press time as to whether Gold has been released on bail.

Along with Gold, federal officials also arrested John Strand, communications director for America's Frontline Doctors, who was pictured with the physician at the event.

Gold joined the mob that stormed Capitol Hill in an attempt to disrupt the 2020 election certification process. She spoke at protests in Washington, D.C., leading up to the riot, casting doubt on the vaccines and claiming that COVID-19 is non-fatal. Gold stated that citizens must not comply with taking "an experimental, biological agent deceptively named a vaccine."

The California-based physician told the Washington Post that she was indeed inside the Capitol, as she followed a crowd and assumed it was legal to do so. Several photos of Gold at the insurrection have circulated online, as well as a video of her making a speech to rioters inside the federal building.


Starting on the day after the riot, federal investigators received photographs of Gold and Strand during the riot. The pair was also captured on video at the doors of the federal building, in the middle of a crowd attempting to push past law enforcement officials to get inside. In this footage, one law enforcement official appeared to be pulled down by someone in the crowd and landed right where Gold and Strand were standing, according to the FBI's affidavit supporting the arrest warrant.

Prior to her involvement on Capitol Hill, Gold gained notoriety for spreading misinformation about the pandemic. Last July, she led a press conference in front of the Supreme Court in which she and other members of America's Frontline Doctors touted the benefits of hydroxychloroquine and criticized lockdown restrictions. Gold has also attempted to sow fear of the COVID-19 vaccines.

Last Updated January 21, 2021

Amanda D'Ambrosio is a reporter on MedPage Today’s enterprise & investigative team. She covers obstetrics-gynecology and other clinical news, and writes features about the U.S. healthcare system. 

Mind the Gap: What '95% Efficacy' Doesn't Tell You

— Questions on COVID vaccines and asymptomatic infection remain unsettled

by Randy Dotinga, Contributing Writer, MedPage Today February 24, 2021



If you've been listening to the news media or even some medical professionals, you might assume the FDA-authorized COVID-19 vaccines are about 95% effective at stopping you from getting infected by the virus. Think again. Despite popular belief, no one knows how well the vaccines actually perform at halting infections overall or preventing transmission. All we understand now is how well they prevent people from becoming significantly sick.


The ability of the vaccines to prevent all infections may seem like an arcane topic compared to their proven ability to stave off moderate-to-severe illness and death. Still, infection prevention "is going to be one of the determinants about how many people die. In effect, you have to vaccinate fewer people to get to herd immunity with a vaccine that protects against infection," Joshua Schiffer, MD, MSc, of Fred Hutchinson Cancer Research Center, told MedPage Today.

Why don't we know more? Because drugmakers have been focused on understanding whether vaccines prevent serious consequences of COVID-19 infection. Asymptomatic cases are secondary, even though they appear to contribute mightily to the spread of the pandemic, and they aren't being as rigorously tracked as moderate-to-severe cases.

This focus makes sense to internist Jeffrey Carson, MD, who managed the Johnson & Johnson COVID-19 vaccine trial's site at Rutgers University in New Jersey. "The logistics of doing a big trial like this are monumental," he told MedPage Today, noting that the J&J trial enrolled about 45,000 people. "Therefore, compromises are made sometimes."


It would be complicated and expensive – but not impossible – to create a vaccine trial that provides rapid data about asymptomatic cases. "You might have people swab themselves every couple days, or every week. You'll be picking up a lot of disease that way, and you'll be able to see if the vaccine prevents asymptomatic disease," Carson said.

However, that kind of trial would be very expensive, he said. Instead, vaccine makers have adopted other approaches. For example, the ongoing Novavax vaccine trial only asks participants to test themselves for COVID-19 via provided swabs if they are directed to do so after developing suspicious symptoms. I'm participating in the Novavax trial, as I reported in a previous MedPage Today article, and I haven't needed to open my packet of swabs.

We don't know much about whether COVID-19 vaccines prevent asymptomatic cases. The publicly available efficacy statistics – 94% to 95% for the FDA-authorized Moderna and Pfizer vaccines -- do not address their ability to prevent cases of COVID-19 with non-existent symptoms, although preliminary Moderna data suggest a lower likelihood of asymptomatic transmission. Additionally, a new study of the Pfizer/BioNTech vaccine in Israel indicated A close up of a Pfizer-BioNTech COVID-19 vaccine vial 92% efficacy in preventing infection -- symptomatic or not -- following the second dose.


As the New York Times helpfully explained, efficacy and effectiveness are not the same thing: "It's possible that the effectiveness of coronavirus vaccines will match their impressive efficacy in clinical trials. But if previous vaccines are any guide, effectiveness may prove somewhat lower."

Unfortunately, vaccine statistics are complicated and can be difficult for even the top minds in medicine to understand. This month, an infectious disease physician told the editors of Lancet Infectious Diseases in a letter that their editorial misunderstood what 94% to 95% efficacy means in regard to the Moderna and Pfizer vaccines and asymptomatic spread.

"It does not mean that 95% of people are protected from disease with the vaccine -- a general misconception of vaccine protection," he wrote. Instead, it "means that in a population such as the one enrolled in the trials, with a cumulated COVID-19 attack rate over a period of 3 months of about 1% without a vaccine, we would expect roughly 0.05% of vaccinated people would get diseased [with symptomatic infections]. ... Accurate description of effects is not hair-splitting; it is much-needed exactness to avoid adding confusion to an extraordinarily complicated and tense scientific and societal debate around COVID-19 vaccines."


Epidemiologist Samuel Scarpino, PhD, director of the Emergent Epidemics Lab at Northeastern University, has similar concerns about lack of insight into the effectiveness of COVID-19 vaccines. "I'm pretty confident that vaccines interrupt transmission, but we don't have data to say that. By not having a clear answer to this, we perpetuate uncertainty. And that's not good for controlling the narrative around the vaccines," he told MedPage Today.

To add to the complexity, scientists are still working to understand how vaccines affect diseases that spread from infected people who don't look or act sick. Most viral diseases, including HIV and hepatitis C, can spread from people who don't realize they're infected. "It makes a lot of sense for survival of the invaders, if you think about it. Humans who feel unwell are not going out to meet up with others, but ones who feel fine will continue along with their daily schedules, allowing the infection to spread," Bryn Boslett, MD, an infectious disease physician at the University of California San Francisco, told MedPage Today.


Scarpino and a colleague authored a 2015 report that suggested asymptomatic spread in vaccinated children may explain outbreaks of whooping cough in the U.S. and U.K. after a new vaccine was introduced. "Over 10 years, a lot of researchers across public health all over the globe have been working on this question about whether the switch in vaccines has increased the rate of asymptomatic individuals," he said.

We're not going to remain in the dark for long about asymptomatic cases of COVID-19 in vaccinated people. Vaccine trials will provide insight over time. For example, in addition to the new Israeli study, Pfizer's December report in the New England Journal of Medicine promised that "a serologic end point that can detect a history of infection regardless of whether symptoms were present (SARS-CoV-2 N-binding antibody) will be reported later."

For now, experts are urging vaccinated people to continue wearing masks and keep away from other people when possible.


"One major worry going forward is that vaccinated people will change their behavior and stop taking COVID-19 precautions," Boslett said. "It's very tempting to do so, very understandable. However, the stars are not yet aligned for us to go back to 'normal.' There is still a lot of COVID-19, and most of us are still vulnerable. We need to continue to focus on behavior to reduce new cases of COVID-19."

Last Updated February 24, 2021

I was the Australian doctor on the WHO’s COVID-19 mission to China. Here’s what we found about the origins of the coronavirus

February 21, 2021

As I write, I am in hotel quarantine in Sydney, after returning from Wuhan, China. There, I was the Australian representative on the international World Health Organization’s (WHO) investigation into the origins of the SARS-CoV-2 virus.

Much has been said of the politics surrounding the mission to investigate the viral origins of COVID-19. So it’s easy to forget that behind these investigations are real people.

As part of the mission, we met the man who, on December 8, 2019, was the first confirmed COVID-19 case; he’s since recovered. We met the husband of a doctor who died of COVID-19 and left behind a young child. We met the doctors who worked in the Wuhan hospitals treating those early COVID-19 cases, and learned what happened to them and their colleagues. We witnessed the impact of COVID-19 on many individuals and communities, affected so early in the pandemic, when we didn’t know much about the virus, how it spreads, how to treat COVID-19, or its impacts.

We talked to our Chinese counterparts — scientists, epidemiologists, doctors — over the four weeks the WHO mission was in China. We were in meetings with them for up to 15 hours a day, so we became colleagues, even friends. This allowed us to build respect and trust in a way you couldn’t necessarily do via Zoom or email.

Listen to ‘Don’t Call Me Resilient,’ a provocative new podcast about raceFind out more

This is what we learned about the origins of SARS-CoV-2.
Animal origins, but not necessarily at the Wuhan markets

It was in Wuhan, in central China, that the virus, now called SARS-CoV-2, emerged in December 2019, unleashing the greatest infectious disease outbreak since the 1918-19 influenza pandemic.

Our investigations concluded the virus was most likely of animal origin. It probably crossed over to humans from bats, via an as-yet-unknown intermediary animal, at an unknown location. Such “zoonotic” diseases have triggered pandemics before. But we are still working to confirm the exact chain of events that led to the current pandemic. Sampling of bats in Hubei province and wildlife across China has revealed no SARS-CoV-2 to date.

We visited the now-closed Wuhan wet market which, in the early days of the pandemic, was blamed as the source of the virus. Some stalls at the market sold “domesticated” wildlife products. These are animals raised for food, such as bamboo rats, civets and ferret badgers. There is also evidence some domesticated wildlife may be susceptible to SARS-CoV-2. However, none of the animal products sampled after the market’s closure tested positive for SARS-CoV-2.

After COVID-19, China brought in new regulations for the trade and consumption of wild animals. Alex Plavevski/EPA/AAP

We also know not all of those first 174 early COVID-19 cases visited the market, including the man who was diagnosed in December 2019 with the earliest onset date.

However, when we visited the closed market, it’s easy to see how an infection might have spread there. When it was open, there would have been around 10,000 people visiting a day, in close proximity, with poor ventilation and drainage.

There’s also genetic evidence generated during the mission for a transmission cluster there. Viral sequences from several of the market cases were identical, suggesting a transmission cluster. However, there was some diversity in other viral sequences, implying other unknown or unsampled chains of transmission.

A summary of modelling studies of the time to the most recent common ancestor of SARS-CoV-2 sequences estimated the start of the pandemic between mid-November and early December. There are also publications suggesting SARS-CoV-2 circulation in various countries earlier than the first case in Wuhan, although these require confirmation.

The market in Wuhan, in the end, was more of an amplifying event rather than necessarily a true ground zero. So we need to look elsewhere for the viral origins.

Read more: Coronavirus: live animals are stressed in wet markets, and stressed animals are more likely to carry diseases

Frozen or refrigerated food not ruled out in the spread

Then there was the “cold chain” hypothesis. This is the idea the virus might have originated from elsewhere via the farming, catching, processing, transporting, refrigeration or freezing of food. Was that food ice cream, fish, wildlife meat? We don’t know. It’s unproven that this triggered the origin of the virus itself. But to what extent did it contribute to its spread? Again, we don’t know.

Several “cold chain” products present in the Wuhan market were not tested for the virus. Environmental sampling in the market showed viral surface contamination. This may indicate the introduction of SARS-CoV-2 through infected people, or contaminated animal products and “cold chain” products. Investigation of “cold chain” products and virus survival at low temperatures is still underway.

Read more: Could frozen food transmit COVID-19?

Extremely unlikely the virus escaped from a lab

The most politically sensitive option we looked at was the virus escaping from a laboratory. We concluded this was extremely unlikely.

We visited the Wuhan Institute of Virology, which is an impressive research facility, and looks to be run well, with due regard to staff health.

We spoke to the scientists there. We heard that scientists’ blood samples, which are routinely taken and stored, were tested for signs they had been infected. No evidence of antibodies to the coronavirus was found. We looked at their biosecurity audits. No evidence.

We looked at the closest virus to SARS-CoV-2 they were working on — the virus RaTG13 — which had been detected in caves in southern China where some miners had died seven years previously.

But all the scientists had was a genetic sequence for this virus. They hadn’t managed to grow it in culture. While viruses certainly do escape from laboratories, this is rare. So, we concluded it was extremely unlikely this had happened in Wuhan.

Read more: British people blame Chinese government more than their own for the spread of coronavirus

A team of investigators

When I say “we”, the mission was a joint exercise between the WHO and the Chinese health commission. In all, there were 17 Chinese and ten international experts, plus seven other experts and support staff from various agencies. We looked at the clinical epidemiology (how COVID-19 spread among people), the molecular epidemiology (the genetic makeup of the virus and its spread), and the role of animals and the environment.

The clinical epidemiology group alone looked at China’s records of 76,000 episodes from more than 200 institutions of anything that could have resembled COVID-19 — such as influenza-like illnesses, pneumonia and other respiratory illnesses. They found no clear evidence of substantial circulation of COVID-19 in Wuhan during the latter part of 2019 before the first case.
Where to now?

Our mission to China was only phase one. We are due to publish our official report in the coming weeks. Investigators will also look further afield for data, to investigate evidence the virus was circulating in Europe, for instance, earlier in 2019. Investigators will continue to test wildlife and other animals in the region for signs of the virus. And we’ll continue to learn from our experiences to improve how we investigate the next pandemic.

Irrespective of the origins of the virus, individual people with the disease are at the beginning of the epidemiology data points, sequences and numbers. The long-term physical and psychological effects — the tragedy and anxiety — will be felt in Wuhan, and elsewhere, for decades to come.

Read more: Yes, we need a global coronavirus inquiry, but not for petty political point-scoring

Author

Dominic Dwyer
Director of Public Health Pathology, NSW Health Pathology, Westmead Hospital and University of Sydney, University of Sydney