Tag: coronavirus

Categories : COVID VaccinesTags :

A Universal Coronavirus Vaccine could Save Millions of Lives in a Future Pandemic

On By ModernMedia
Photo by Mika Baumeister on Unsplash

What if in the years prior to the COVID pandemic, scientists had developed a universal coronavirus vaccine, one that targets parts common to coronaviruses, offering some protection against all strains? Would it have been of help during the pandemic?

A new study suggests if such a vaccine were available at the start of the pandemic, it could have saved millions of lives, prevented suffering, and saved billions of dollars in direct medical and other costs until the strain-specific (ie, SARS-CoV-2) vaccine went through the entire development, testing, and emergency use authorisation process that lasted 10 months.

In this study, published in The Lancet’s eClinicalMedicine, researchers show that having a universal vaccine at the start of the pandemic would have had substantial health and economic benefits under almost all scenarios tested.

In order to determine the value of investing in developing and stockpiling a universal coronavirus vaccine, the team developed a computational model that simulated the entire US population, the introduction and spread of a novel coronavirus like SARS-CoV-2 in 2020 and the resulting health (eg, infections, hospitalisations) and economic (eg, direct medical costs, productivity losses) outcomes.

The experiments simulated what would happen if a universal coronavirus vaccine was available at the start of the COVID pandemic.

Vaccinating with a universal coronavirus vaccine as a standalone intervention (e.g., no face mask use or social distancing) was cost-saving even when its efficacy was as low as 10% and only 10% of the U.S. population received the vaccine.

For example, when a universal coronavirus vaccine has 10% efficacy, vaccinating a quarter of the U.S. population within two months of the start of the pandemic averts an average of 14.6 million infections and saves over $27 billion in direct medical costs.

Such low vaccine coverage at the start of the pandemic could occur if a vaccine were only made available to certain high-risk subpopulations (eg, 65 years and older, the immunocompromised, frontline workers), similar to the approach when mRNA vaccines became available in December 2020.

“COVID-19 was the third major and serious coronavirus epidemic or pandemic following SARS in 2002 and MERS in 2012, thus, we should anticipate a fourth coronavirus outbreak within the next decade or so,” says Peter J. Hotez, MD, PhD, dean of Baylor’s National School of Tropical Medicine and co-director of the Texas Children’s Hospital Center for Vaccine Development.

“A universal vaccine is cost-effective and cost-saving and a priority for advancement.”

A universal coronavirus vaccine was also shown to be highly cost-effective even if a more specific and more efficacious vaccine came to market.

For example, the study shows if it takes four months or longer for a strain-specific vaccine to reach the market, using a universal vaccine was still cost cost-saving.

In a scenario where a strain-specific vaccine has 90% efficacy but is unavailable for two months after the start of the pandemic, the results from the model show that vaccinating only 10% of the population with a universal vaccine that has 10% efficacy at the start of the pandemic can save over $2 billion in societal costs (eg, direct medical costs and productivity losses from absenteeism). Given the time required to develop a strain-specific vaccine during a pandemic to match circulating strains of the virus, this highlights the importance of having a universal vaccine readily available as a stopgap.

“Our study shows the importance of giving as many people as possible in a population at least some degree of immune protection as soon as possible,” explains Bruce Y. Lee, MD, MBA, executive director of PHICOR and professor at CUNY SPH.

“Having a universal vaccine developed, stockpiled, and ready to go in the event of a pandemic could be a game-changer even if a more specific vaccine could be developed three to four months later.”

Generally, results from the model found that a universal vaccine would end up saving money if the cost to get a person vaccinated (eg, cost of the vaccine itself, distribution, administration, storage, research, and development) is as high as $10 390 from a societal perspective.

Source: CUNY Graduate School of Public Health and Health Policy

Categories : COVIDTags :

Which Entryway a Coronavirus Uses Affects its Infection Severity

On By ModernMedia
Image by Fusion Medical on Unsplash

Until now, the reason why some coronaviruses such as SARS-CoV-2 affect humans more severely than other seasonal ones has eluded scientists. Now, results published in Nature have provided a piece of the puzzle by identifying a gateway used by the seasonal coronavirus HKU1 to enter human cells. HKU1 binds to a different receptor than SARS-CoV-2, which may partly explain the difference in severity between these two coronaviruses.

Receptors provide a useful means of figuring out coronavirus transmissibility and pathology as part of surveillance work on viral evolution. Seven coronaviruses are known for their ability to infect humans. Four of these are generally mild: HKU1, 229E, NL63 and OC43, while the other three are more pathogenic: SARS-CoV-1, Mers-CoV and SARS-CoV-2.

The HKU1 virus was first identified in an elderly patient with severe pneumonia in Hong Kong in 2005. Like SARS-CoV-2, HKU1 mainly infects upper respiratory tract cells. However, it rarely affects the bronchi and alveoli in the lungs. The HKU1 virus causes colds and other mild respiratory symptoms. Complications may also occur, including severe respiratory tract infections, particularly in young children, the elderly and immunocompromised individuals. It is estimated that 70% of children are infected before the age of 6. In total, 75 to 95% of the global population has been exposed to HKU1, which is comparable to other seasonal human coronaviruses.

At the cellular level, coronavirus spike proteins are cleaved after binding to their receptors. This cleavage phenomenon is vital for viral fusion, entry and multiplication. Some coronaviruses (SARS-CoV-2 and NL63) use the ACE2 receptor as a gateway for entering cells. Until now, HKU1 and OC43 were the only coronaviruses with unknown receptors.

Through collaboration between scientists at eight Institut Pasteur units, it was possible to identify the TMPRSS2 enzyme as the receptor to which HKU1 binds to enter cells. Once binding has occurred, TMPRSS2 triggers fusion of HKU1 with the cell, leading to viral infection. Through a combination of techniques performed in vitro and in cell culture, the scientists demonstrated that the TMPRSS2 receptor has high affinity with the HKU1 spike, which is not the case for SARS-CoV-2.

“Once a receptor has been identified for a virus, it is possible to characterise target cells more accurately, while also gaining insights on viral entry and multiplication mechanisms and infection pathophysiology,” comments, Olivier Schwartz, co-last author of the study and Head of the Institut Pasteur’s Virus and Immunity unit.

“Our findings also shed light on the various evolution strategies employed by coronaviruses, which use TMPRSS2 either to bind to target cells or trigger fusion and viral entry,” adds Julian Buchrieser, co-last author of the study and scientist in the Institut Pasteur’s Virus and Immunity unit.

These human-pathogenic viruses’ use of different receptors probably affects their degree of severity. Receptor levels vary among respiratory tract cells, thus influencing the sensitivity of cells to infection and viral spread. Once the route of viral entry into cells is known, it should also be possible to fight infection more effectively by developing targeted therapies and assess the risk of virulence posed by any future emerging coronaviruses.

In parallel with this work, Institut Pasteur teams led by Pierre Lafaye and Felix Rey have developed and characterised nano-antibodies (very small antibodies) that inhibit HKU1 infection by binding to the TMPRSS2 receptor. These reagents have been patented for potential therapeutic activities.

Source: Institut Pasteur

Categories : COVID PaediatricsTags :

Common Cold may Have Conferred COVID Immunity to Children

On By ModernMedia
Young girl sneezing
Photo by Andrea Piacquadio on Unsplash

Early in the COVID pandemic, it became clear that children infected with the coronavirus rarely developed serious disease. One hypothesis has been that children already have some immunity provided by memory T cells generated by common colds. Researchers at Karolinska Institutet are now able to show that OC43, one of the coronaviruses that cause common colds, boosts the immune response to COVID. The study, which is published in PNAS, could give rise to more tailored vaccine programmes for children and adults.

After studying unique blood samples from children taken before the pandemic, Karolinska Institutet researchers have now identified memory T cells that react to cells infected with SARS-CoV-2.

This new study reinforces this hypothesis and shows that T cells previously activated by the OC43 virus can cross-react against SARS-CoV-2.

Four coronaviruses cause common colds

One of the four coronaviruses causing seasonal common cold symptoms could stimulate an immune response with T cells able to also react to cells infected with SARS-CoV-2.

“These reactions are especially strong early in life and grow much weaker as we get older,” says the study’s corresponding author Annika Karlsson, research group leader at the Department of Laboratory Medicine, Karolinska Institutet. “Our findings show how the T-cell response develops and changes over time and can guide the future monitoring and development of vaccines.”

Strong immunity at the age of two

The results indicate that the memory T-cell response to coronaviruses develops as early as the age of two. The study was based on 48 blood samples from two- and six-year-old children, and 94 samples from adults between the ages of 26 and 83. The analysis also included blood samples from 58 people who had recently recovered from COVID-19.

“Next, we’d like to do analogous studies of younger and older children, teenagers and young adults to better track how the immune response to coronaviruses develops from childhood to adulthood,” says Marion Humbert, postdoctoral researcher currently at the Department of Medicine Huddinge, Karolinska Institutet, joint first author with Anna Olofsson, doctoral student at the Department of Laboratory Medicine.

Source: Karolinska Institutet

Categories : COVIDTags :

Immunity to Other Coronaviruses Confers COVID Protection

On By ModernMedia
Transmission electron micrograph of SARS-CoV-2 virus particles (gold) within endosomes of a heavily infected nasal Olfactory Epithelial Cell. Image captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Credit: NIAID

Researchers have discovered another component beside previous infection or vaccination that contributes to SARS-CoV-2 immunity – previous antibody responses to other, harmless coronaviruses. “People who have had strong immune responses to other human coronaviruses also have some protection against SARS-CoV-2 infection,” said Alexandra Trkola, head of the Institute of Medical Virology at University of Zurich.

The study, published in Nature Communication, used a specially developed assay to analyse antibody levels against four other human coronaviruses in 825 serum samples taken before  the emergence of SARS-CoV-2, as well as 389 samples from donors infected with the virus. Combining these analyses with computer-based models enabled the team to precisely predict how well the antibodies would bind to and neutralise invading viruses.

The researchers were able to demonstrate that people who caught SARS-CoV-2 had lower levels of antibodies against coronaviruses that cause common colds compared to uninfected people. In addition, people with high levels of antibodies against harmless coronaviruses were less likely to have been hospitalized after catching SARS-CoV-2. “Our study shows that a strong antibody response to human coronaviruses increases the level of antibodies against SARS-CoV-2. So someone who has gained immunity to harmless coronaviruses is therefore also better protected against severe SARS-CoV-2 infections,” says Trkola. This type of immune response is referred to as cross-reactivity, and it also occurs with T cell responses,  the additional line of the immune system in the defense against infections.

People are only fully protected against SARS-CoV-2 shortly after they have recovered from an infection or have received an effective vaccination. This is when antibody levels against the virus are still very high. As these levels drop over time, infection is no longer prevented, but the immunological memory quickly reactivates the body’s defenses, the production of antibodies as well as the T cell defense. “Of course, immune responses targeting SARS-CoV-2 that are mounted by the memory cells are far more effective than cross-reactive responses. But even though the protection isn’t absolute, cross-reactive immune responses shorten the infection and reduce its severity. And this is exactly what is also achieved through vaccination, just much, much more efficiently,” said Trkola.

Whether cross-reactivity also works in the opposite direction is not yet known. “If SARS-CoV-2 immunity also offers some degree of protection from infection with other coronaviruses, we would be a significant step closer to achieving comprehensive protection against other coronaviruses, including any new variants,” the virologist explains. This idea is also supported by the fact that cross-reactive protection is not only based on antibodies, but very likely also on T cells.

Source: University of Zurich

Categories : COVID GeneticsTags :

Bat Coronavirus 94.5% Similar to SARS-CoV-2 Found

On By ModernMedia

Researchers in China and Australia have reported the discovery of novel bat coronaviruses with a similarity of up to 94.5% to SARS-CoV-2. 

This finding further illuminates the diversity and complex evolutionary history of these viruses. A pre-print version of the research paper is available on the bioRxiv server.

Now, Weifeng Shi from Shandong First Medical University & Shandong Academy of Medical Sciences in Taian, China and colleagues have conducted a meta-transcriptomic analysis of samples collected from 23 bat species in Yunnan province in China during 2019 and 2020.  

Using a combination of genome sequencing and sampling studies, researchers identified a number of SARS-CoV-2-related coronaviruses in wildlife species that together pointed to underestimation of the phylogenetic and genomic diversity of coronaviruses.

“Our study highlights both the remarkable diversity of bat viruses at the local scale and that relatives of SARS-CoV-2 and SARS-CoV circulate in wildlife species in a broad geographic region of Southeast Asia and southern China,” said the team.

Bats are hosts to a broad range of viruses that can infect humans, and four of the seven known human coronaviruses have zoonotic origins.  They are also host to many coronaviruses, but sometimes “intermediate” hosts such as dromedary camels (MERS-CoV) are involved in the jump to humans.

Retrospective genome sequencing and sampling studies identified a number of SARS-CoV-2-related coronaviruses in wildlife species. These included the RaTG13 virus, which is the closest known relative of SARS-CoV-2,  found in the Rhinolophus affinis bat. SARS-CoV-2-related viruses have also been identified in various other Rhinolophid bats across Asia.

“Collectively, these studies indicate that bats across a broad swathe of Asia harbour coronaviruses that are closely related to SARS-CoV-2 and that the phylogenetic and genomic diversity of these viruses has likely been underestimated,” said Shi and colleagues.

Notably, one of these novel bat coronaviruses – RpYN06 – exhibited 94.5% sequence identity to SARS-CoV-2 across the whole genome, with key similarities in certain genes. Low genopmic sequence identity in the spike gene made RpYN06 the second closest relative of SARS-CoV-2, next to RaTG13. This is far more similar than seen in other SARS-CoV-2-like viruses identified in wildlife species.

Indeed, while the other three SARS-CoV-2-related viruses identified here were almost identical in sequence, the spike protein sequences formed an independent lineage that was separated from known sarbecoviruses (a  viral subgenus or the coronaviruses that  includesSARS-CoV-2)   by a relatively long branch.

“Collectively, these results highlight the extremely high, and likely underestimated, genetic diversity of the sarbecovirus spike proteins, which likely reflects their adaptive flexibility,” wrote Shi and colleagues.

The researchers say studies have previously shown that host switching of coronaviruses among bats is a frequent occurrence.

Source: News-Medical.Net

Journal information: Shi W, et al. Identification of novel bat coronaviruses sheds light on the evolutionary origins of SARS-CoV-2 and related viruses. bioRxiv. 2021. doi: https://doi.org/10.1101/2021.03.08.434390

Categories : UncategorizedTags :

Improved Treatment Results in 18% Fall in COVID Death Rates

On By ModernMedia

In a piece for The Conversation, Professor Monica Gandhi at the University of California, writes how, thanks to improved treatment as a results of experience gained, survival rates for COVID patients have dramatically risen.

In three New York hospitals, out of 1724 patients hospitalised for COVID in March, 430 died. In August, 134 hospitalised and five died. However, this may have been due to more vulnerable patients being infected. Therefore, to avoid bias, the researchers accounted for age of patients at hospitalisation, race, amount of oxygen support individuals needed on arrival and such risk factors as being overweight, smoking, high blood pressure, diabetes, lung disease. Even so, they found that patients were three times as likely to survive when admitted in August as compared to March, which indicates that this is due to improved treatment resulting from research into and experience with the disease.

A similar study in the UK looked at COVID patient survival rates in high-dependency units (HDU) and ICU, and found a continuous improvement in survival rates of 12.7% per week in the HDU and 8.9% per week in ICU.

Prof Gandhi attributes this to a better understanding of the disease, and the regular use of remdesivir and dexamethasone as treatments.

Source: The Conversation

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Extreme “Super-spreader” Events Boost COVID Spread

On By ModernMedia

The SARS-CoV-2 virus has a reproduction number of three, indicating that on average it will infect three other individuals over the course of the infection. However, a study at the Massachusetts Institute of Technology (MIT) found that extreme “super-spreader” events, such as the one that happened at a White House event in September, seem to generate more infections than would otherwise be expected due to random distributions.

“Super-spreading events are likely more important than most of us had initially realized. Even though they are extreme events, they are probable and thus are likely occurring at a higher frequency than we thought. If we can control the super-spreading events, we have a much greater chance of getting this pandemic under control,” said James Collins, the Termeer Professor of Medical Engineering and Science in MIT’s Institute for Medical Engineering and Science (IMES) and Department of Biological Engineering, and the senior author of this study. 

The researchers analysed a number of documented “super-spreader events” that have taken place over the COVID pandemic. When they ran statistical analyses on super-spreader events, they found that instead of the expected “bell curve” of normal distribution, they found a “fat tail” of extreme events.

Lead author, MIT postdoc Felix Wong said, “This means that the probability of extreme events decays more slowly than one would have expected. These really large super-spreading events, with between 10 and 100 people infected, are much more common than we had anticipated.”

Source: Medical Xpress

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Speech Recognition AI Detects COVID in Coughs

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An AI system originally developed at the Massachusetts Institute of Technology (MIT) to research speech patterns in people with Alzheimer’s was repurposed when the COVID pandemic hit to become an indicator for COVID in asymptomatic patients. 

“The sounds of talking and coughing are both influenced by the vocal cords and surrounding organs,” says research scientist Brian Subirana of MIT.
“This means that when you talk, part of your talking is like coughing, and vice versa. It also means that things we easily derive from fluent speech, AI can pick up simply from coughs, including things like the person’s gender, mother tongue, or even emotional state. There’s in fact sentiment embedded in how you cough.”

The system was based on a neural network that was trained on a thousand hours of human speech, then on a database on words spoken in different emotional states and finally a database of coughs. The result was a system that could detect a cough in an asymptomatic person with COVID with 97.1% accuracy. However, this is not a true test of COVID but an enhanced early indicator. The advantage of this technology is that it can be developed as an early warning system that can be incorporated into something as ubiquitous as a smartphone.

Source: Science Alert

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COVID DNA of White House “Superspreader Event” Analysed

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On September 26, numerous high-profile individuals, contracted COVID at a large official White House gathering. This White House “superspreader event” as it was known became something of a case study in how COVID can spread in large groups of people.

Although President Trump contracted the virus, it is not known if this was a result of attending that event. The event, which had over a dozen guests, resulted in 34 individuals including White House staff testing positive for COVID by October 7.

Whilst contact tracing is difficult with COVID, genome sequencing offers a chance for insights into its development and spread. The researchers analysed SARS-CoV-2 genomes from nasal swabs taken from the patients at the White House superspreader event, and analysed it, looking for mutations. They found two variants, WH-2 and WH-2. They determined that these viruses descended from those widely in circulation in Florida, New York, Texas, Connecticut, and Washington – as well as certain countries such as  New Zealand.

Source: News-Medical.Net

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Rights Group Supports No Patents for COVID Vaccines

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Business Live reports on the recent call by South Africa and India for COVID vaccines not to be patented. Human Rights Watch added its support by stating that vaccines obtained by public funding should be shared as widely as possible, and their intellectual property status waived.

Some 44 vaccine candidates are being trialled around the world. Wealthy countries have placed orders in order to secure stockpiles of the vaccines. South Africa has no vaccine scheme of its own and is instead has expressed interest in (without signing up to) the global Covax scheme, which involves the World Health Organization and which aims to have two billion doses to be shipped out by the end of 2021.

HRW researcher Margaret Wurth said, “You can’t fight a global pandemic by allowing publicly funded vaccines to go to the highest bidder, at whatever price pharmaceutical companies set. When a safe and effective vaccine is found, it should be available and affordable for everyone, everywhere.”