Category: Uncategorized

Extreme “Super-spreader” Events Boost COVID Spread

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

UV Key to Seasonality of Airborne Respiratory Diseases

It has long been observed that flu seasons in the northern hemisphere tend to last over autumn and winter, while in regions closer to the equator, they tend to have a year-round prevalence.

A group of Italian researchers believe that the sun – specifically its UV rays, which are known to inactivate various pathogens – holds the key. This periodic change in UV radiation over the seasons resonates with another cyclical event – the loss of resistance in the host over half a year of antigenic drift. The researchers incorporated these effects into a series of models, which reflect the seasonality of airborne respiratory diseases.

“From an epidemiologic point of view, these models clarify an important and long-standing mystery: why do influenza epidemics disappear every year when the number of susceptible individuals is still very far from that needed to trigger the herd immunity mechanism?” said Mario Clerici, Immunologist at the University of Milan and the Don Gnocchi Foundation.
“The Italian data of the SARS-CoV-2 pandemics can also be described accurately by our model,” said Fabrizio Nicastro, INAF researcher and PI of the work, “but the predictive power of the model depends critically (other than on the implementation of new restriction measures) on the exact UV-B/A lethal doses for the COVID-19 virus, which our collaboration is about to measure.”

Source: Medical Xpress

Speech Recognition AI Detects COVID in Coughs

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

COVID DNA of White House “Superspreader Event” Analysed

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

Hypertension at Night Raises Cardiovascular Disease Risk

An eight year long study conducted in Japan added to the evidence that hypertension during the night raises cardiovascular disease risk, especially compared to the daytime. 

Hypertension levels are usually assessed during the day, and do not give an accurate snapshot of a person’s circadian rhythm.  According to lead author of the study, Kazuomi Kario, MD, PhD, hypertension at night, especially when blood pressure is lower during the day, raises cardiovascular disease risk and is increasingly being recognised as a risk factor. Kario said, “This study provides much more in-depth information about the cardiovascular risk associated with high nighttime blood pressure and different nighttime blood pressure phenotypes than have been reported previously.”

The Japan Ambulatory Blood Pressure Monitoring Prospective (JAMP) study enrolled 6359 patients and measured daytime and nighttime levels using an at-home, wearable, ambulatory monitor. They were told to conduct their daily routine as normal, and to rest or sleep during the night. The results showed that elevated blood pressure during the night compared to the day was a significant indicator of raised cardiovascular disease risk. Patients who were hypertensive and then had a large dip in systolic pressure had a greater risk for stroke.

“Results indicate that nighttime systolic blood pressure was a significant, independent risk factor for cardiovascular events,” said Dr Kario. “The study highlights the importance of including nighttime blood pressure monitoring in patient management strategies and will hopefully encourage physicians to ensure that antihypertensive therapy is effectively lowering blood pressure throughout the 24-hour dosing period.”

Source: Medical Xpress

Research Suggests Vitamin C Beneficial for Severe COVID

According to Associate Professor Anitra Carr of Otago University in New Zealand, research provides evidence that large doses of Vitamin C is beneficial for severe COVID. A 2019 study previously showed that giving Vitamin C to patients with Acute Respiratory Distress reduced mortality rates.

“A recent study that came out of the US showed that patients with coronavirus in ICU with Covid-19 also had very low vitamin C levels,” Carr said. “That’s because the body chews through a lot more of it when you get an infection – and your requirements increase significantly. But the standard doses given in the intensive care unit aren’t enough to compensate, given a severe case of the disease comes with a huge inflammatory response and oxidative stress.”

 Carr said that delivering the drug intravenously was critical to supplying the high levels of Vitamin C needed. One study from Wuhan, China showed Vitamin C conferred a survival benefit to placebo, though Carr noted that many more studies are needed and will come throughout the next year.

However, besides its normal dietary role, there was little research to show that Vitamin C had much of a preventative role. Carr said, “Some research has shown that, if you’re under enhanced stress, your risk for infection increases, so in those people vitamin C may decrease the risk of getting it. But in the general everyday population, who aren’t under extreme physical stress, it may not decrease your chances of catching the disease.”

Source: NZ Herald

Rights Group Supports No Patents for COVID Vaccines

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.”

Breast Cancer Patients in Public Healthcare System Face Great Obstacles

In an in-depth article, the Daily Maverick reports on the huge challenges that breast cancer sufferers face in obtaining treatment from the public healthcare sector in South Africa.

A diagnosis might take up to six months, whereas one can be obtained in a space of weeks in private healthcare. Breast reconstructions are not available under public healthcare, forcing the survivor to find some way of hiding the disfigurement. The critical drug trastuzumab is classed as an unfunded mandate even in the Western Cape. Yet in the private sector, it is a prescribed minimum benefit. There are language barriers for patients, and a lack of palliative care medicines upon discharge. They also are not connected online, and cannot engage with initiatives such as Pinktober. In a country beset by gender-based violence and inequality, women’s health often is not a priority.

The remedy still lags very far behind. Since its inception in 2017, The Breast Cancer Control Policy has not been implemented anywhere in South Africa. In order to implement this policy, registered nurses have their job descriptions updated to include a primary modality of breast cancer screenings.

The COVID pandemic has set back progress even further, with care being postponed and many hospices being forced to close.

Cutting Edge Bio-printing Fabricates Tiny Kidneys

Researchers from the Murdoch Children’s Research Institute (MCRI) and biotech company Organovo have successfully bio-printed miniature human kidneys with unparalleled speed and quality to be used for toxicity screening of medications known to cause kidney damage. 

A world leader in modeling the kidney, Professor Melissa Little of the MRCI said, “Drug-induced injury to the kidney is a major side effect and difficult to predict using animal studies. Bioprinting human kidneys are a practical approach to testing for toxicity before use.”

The new study involved testing the toxicity of aminoglycosides, a class of antibiotics that commonly damage the kidney. The study revealed deaths of certain types of kidney cells when exposed to aminoglycosides.

Organovo first began bio-printing kidneys in 2015, but their new processes are much faster, allowing 200 mini-kidneys to be produced in 10 minutes. The improvement in speed and quality has opened the doorway for bioprinting entire organs for transplant. “3-D bioprinting can generate larger amounts of kidney tissue but with precise manipulation of biophysical properties, including cell number and conformation, improving the outcome.”

Professor Little said that prior to this study, the possibility of using such technology for transplantation was too complicated to consider. “The pathway to renal replacement therapy using stem cell-derived kidney tissue will need a massive increase in the number of nephron structures present in the tissue to be transplanted,” she said.

“By using extrusion bioprinting, we improved the final nephron count, which will ultimately determine whether we can transplant these tissues into people.”

Source: Medical Xpress

Anaesthetic Clues Hidden in Tarantula Venom

In a finding that promises new research into pain management, a tarantula toxin molecule has been revealed to use a “stinger” to permanently close the voltage sensors on nerve cells’ sodium channels.

Chronic pain is difficult to treat, and attempts to seek relief can sometimes lead to opiate overdose, addiction, prolonged withdrawal, and even death. This means that there is a critical need to develop pain management medications that are safer, more effective and non-addictive. Tarantula toxin is of interest because it has to be fast-acting, shutting down the nerves of the tarantula’s prey and immobilising it before it can escape.

The tarantula toxin’s mechanism of action has proved elusive: the tarantula toxin-ion channel chemical complex has been hard to capture in its functional form. This has made it especially challenging to replicate the calcium-channel blocking effect in a small molecular form suitable for anaesthetic compounds. To overcome this obstacle, the researchers took a toxin-binding region from a specific type of human sodium channel that is key to pain transmission and imported it into their bacterium-derived model ancestral sodium channel. In doing so, they successfully obtained a clear molecular view of the configuration of the potent toxin from tarantula venom as it tightly binds to the sodium channel receptor site.

Prof William Catterall of the University of Washington School of Medicine explains: “Remarkably, the toxin plunges a ‘stinger’ lysine residue into a cluster of negative charges in the voltage sensor to lock it in place and prevent its function. Related toxins from a wide range of spiders and other arthropod species use this molecular mechanism to immobilise and kill their prey.”

The researchers hope that these insights will lead to the development of a new variety of anaesthetic compounds.

Source: News-Medical.Net