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Researchers Detail More Clot Cases Associated with the COVID Vaccine | Instant News

Editor’s note: Find the latest COVID-19 news and guides on Medscape’s Coronavirus Resource Center.

New evidence emerged today linking a vaccine for COVID-19 to the very rare cases of people with low blood clots. platelets within a few weeks of being vaccinated.

A team of researchers in the UK carried out an in-depth investigation of 22 patients who had serious blood clots combined with decreased blood platelets after receiving a dose of the AstraZeneca vaccine, now called Vaxzevria. They also tested additional patients who had clinical signs of decreased blood platelets after vaccination. Nearly all of the patients – 22 of 23 – tested positive for the unusual antibody to platelet factor 4, a signaling protein that helps the body coordinate blood clotting.

The presence of antibodies indicates that the vaccine somehow triggers an autoimmune attack that causes large clots to form which then reduces the supply of platelets in the blood.

Study and editorial about the cases published on New England Journal of Medicine.

This is at least third study detailed the presence of these antibodies in patients with blood clots and low platelets after vaccination, and doctors say emerging evidence suggests that doctors should remain alert for this new syndrome in anyone with symptoms of blood clots anywhere in the body, not just in the brain. .

James Zehnder, MD, director of the coagulation laboratory at Stanford University School of Medicine in California, says there is growing evidence that the “maladaptive immune response” is quite extraordinary. He was not involved in the research.

Zehnder says why this syndrome, which appears to be a kind of autoimmune attack on blood signaling proteins, develops in a small number of people after they get an anticoagulant. heparin or a vaccine for COVID-19 is still a mystery.

He said that while catastrophic cases of large lumps in areas of the brain where doctors usually don’t see them stand out, he wonders if other, less obvious cases have gone undetected.

“Then the question is, you know, how much of this is going on in a more subtle way? So I think the real magnitude is unknown,” he said, noting that this will be important in the coming weeks. and months to find out if certain groups of people are at a higher risk than others, such as young women. “There are more questions than answers now,” he said.

Main Symptoms to Pay Attention to

Symptoms to watch for include shortness of breath, headache, dizziness, muscle weakness, or stomach pain. back pain, or nausea and vomiting in anyone within 3 weeks of vaccination, including men.

People who haven’t been vaccinated can also develop a type of clot called a cerebral venous sinus thrombosis. These cases – whether they occur after vaccination or not – are very rare. On average each year, there are two to 14 cases of these clots in the vessels that drain blood from the brain for every million people, according to Peter Marks, of the US Food and Drug Administration.

Doctors say that, overall, all vaccines passed to protect people from the new coronavirus are very safe. In fact, the risk of developing life-threatening blood clots is much higher with COVID than with vaccines.

“The odds of this happening to you are between 1 and 100,000 to 1 in 1 million,” says John Wherry, PhD, director of the Institute for Immunology at the University of Pennsylvania in Philadelphia. “If you are an American, the chance of dying from COVID is 1 in 600,” continued Wherry, citing statistics on US COVID cases and deaths administered by Johns Hopkins University.

In a presentation to the Centers for Disease Control and Prevention this week, representatives from the vaccine manufacturer Johnson & Johnson said they had found a 25-year-old man who developed rare clots in his brain and low platelets during their clinical trials. When they came back and tested the stored blood, they found he also had signaling antibodies to platelet factor 4, making him the 7th case known to be linked to the vaccine in the United States. He has recovered.

Investigators initially dismissed her case as unrelated to vaccines because another study participant, a 24-year-old woman, also developed a similar blood clot in her brain, but she was in the placebo group. He’s just been prescribed it birth control pills, which increase a woman’s risk of blood clots and strokes like she has.

An eighth case, possibly related to the Johnson & Johnson vaccine, is still being investigated in the United States.

Wherry said it was not surprising that these rare cases went undetected in clinical trials involving tens of thousands of people. He said that very rare events are sometimes only revealed when drugs or devices are used in the millions, such as vaccines now.

He said that the fact that this event was detected completely means that the safety surveillance system is working.

“We did everything right,” he said. “It would be unfortunate and traumatic if that happened, but in terms of the risk to benefit ratio we still have to put the numbers in perspective and now that we have captured many of these events we now have an idea of ​​what to do when we see it,” Wherry added. .

British case

Among the 22 cases identified in the new UK study, 16 (70%) were under 50 years of age, and 14 (61%) were women. All were healthy before developing rare clots. No one was taking drugs that were linked to clotting or bleeding. Some present with light bruising and small red spots called petechiae, which indicate bleeding under the skin.

This collection of symptoms, severe clotting combined with decreased platelets, is nothing new. Doctors recognize it as a sign that a person is experiencing a rare, severe reaction to the anticoagulant heparin. In patients taking heparin, this is called HIT, for heparin-induced thrombocytopenia.

Doctors investigating symptoms in the new COVID vaccine setting call it vaccine-induced thrombotic thrombocytopenia, or VITT.

The authors of the UK study found that the usual site of care test used to detect HIT – the HemosIL AcuStar HIT IgG test – was often negative for patients with VITT. They say VITT needs to be confirmed with a different type of test, ELISA or enzyme-linked immunosorbent assay.

Patients with VITT also need a different type of treatment than is usually given to people who experience dangerous blood clots or bleeding. Giving platelets, for example, to stop bleeding can make things worse. Instead, they require IVIG treatment to reduce obvious autoimmune attacks. Researchers say that, until more is known, it is also best to use an anticoagulant other than heparin to treat clotting.

Wherry said he wasn’t surprised to see some men affected, but so far, the emerging picture suggests women are at greater risk.

She said women tend to be more prone to autoimmune diseases and also more prone to blood clots due to these hormones. estrogen.

“So it fits this idea that this might be, you know, an indicator of some autoimmune bias,” he said.

NEJM. Published online April 16, 2021. Full text, Editorial

Several co-authors report receiving personal payments from one or more of the following companies: Bayer, Bristol Myers Squibb, Daiichi Sankyo, Pfizer, Novartis, Octapharma, Sanofi, Sobi, Alexion, and Takeda. Co-author of the grant report from Shire and Novartis; one of the authors reported another financial relationship with GSK; and a co-author reported on patent testing for bacterial meningitis based on a blood test, filed a patent pending decision.

Wherry reports consulting agreements with and / or is scientific advisor to Merck, Roche, Pieris, Elstar, and Surface Oncology. He has a PD1 patent licensing agreement with Roche / Genentech and is the founder of Arsenal Biosciences.

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How COVID-19 affects the nervous system | Instant News

A new paper published in the journal JAMA Neurology in May 2020 discussed the presentation and complications of COVID-19 with respect to the nervous system.

The COVID-19 pandemic has caused hundreds of thousands of cases of severe pneumonia and respiratory disorders, in 188 countries and regions in the world. The causative agent, SARS-CoV-2, is a new coronavirus, with well-recognized lung complications. However, evidence is increasing that the virus also affects other organs, such as the nervous system and heart.

The Coronaviruses: A Glimpse

That corona virus is a group of large spread RNA viruses that infect animals and humans. Human infections are known to be caused by 7 coronaviruses, namely human coronavirus (HCoV) –229E, HCoV-NL63, HCoV-HKU1, HCoV-OC43, MERS-CoV, SARS-CoV-1, and SARS-CoV-2.

Among these, the last three are known to cause severe human disease. While HCoV is more associated with respiratory manifestations, three of them are known to infect neurons: HCoV-229E, HCoV-OC43, and SARS-CoV-1.

Current research aims to contribute to the knowledge of the SARS-CoV-2 neurotropism, as well as post-infectious neurological complications. This virus infects humans through ACE2 receptors in various tissues, including airway epithelium, kidney cells, small intestine, proper lung tissue, and endothelial cells.

Because endothelium is found in blood vessels throughout the body, this offers a potential route for CoV to be localized in the brain. In addition, a recent report shows that ACE2 is also found in brain neurons, astrocytes, and oligodendrocytes, especially in areas such as substantia nigra, ventricles, middle temporal gyrus, and olfactory bulb.

Interestingly, ACE2 in neuron tissue is expressed not only on the surface but also in the cytoplasm. This finding could imply that SARS-CoV-2 can infect neuronal and glial cells in all parts of the central nervous system.

How does neuroinvasion occur with SARS-CoV-2?

Current knowledge indicates the possibility of nerve cell virus invasion by several mechanisms. These include the transfer of viruses across synapses of infected cells, entering the brain through the olfactory nerve, infection of endothelial blood vessels, and migration of infected white blood cells across the blood-brain barrier (BBB).

The corona virus has been shown to spread back along the nerves from the edge of the peripheral nerves, across synapses, and thus into the brain, in several small animal studies. This is facilitated by a pathway for endocytosis or exocytosis between motor cortex neurons, and other secretory vesicular pathways between neurons and satellite cells.

Axonal transport occurs rapidly using axonal microtubules, which allow the virus to reach the body of neuron cells with a retrograde version of this mechanism.

The possibility of spreading the olfactory route is marked by the occurrence of isolated anosmia and age. In such cases, the virus can pass through the latticed plate to enter the central nervous system (CNS) of the nose. However, more recent unpublished research shows that olfactory neurons lack ACE2, whereas cells in the olfactory epithelium do so. This could mean that a viral injury to the olfactory epithelium, and not the olfactory neuron, is responsible for anosmia, but further studies will be needed to confirm this.

Cross the BBB

This virus can also pass through the BBB through two separate mechanisms. In the first case, infected vascular endothelial cells can move the virus across blood vessels to neurons. Once there, the virus can start to bud and infect more cells.

The second mechanism is through infected white blood cells that pass through the BBB – a mechanism called Trojan horse, which is famous for its role in HIV. Inflamed BBB allows the entry of immune cells and cytokines, and even, possibly, viral particles into the brain. T-lymphocytes, however, do not allow viruses to replicate even though they can be infected.

Neurological features of COVID-19

From limited data on neurological manifestations related to COVID-19, it is clear that headaches, anosmia, and age are among the most common symptoms. However, other findings include stroke and an abnormal state of consciousness.

While headaches occur in up to one third of confirmed cases, anosmia or age shows a much more varied prevalence. In Italy, about one fifth of cases show this symptom, while almost 90% of patients in Germany have such symptoms.

The researchers said, “Given the reports of anosmia that appear as early symptoms of COVID-19, specific testing for anosmia can offer the potential for early detection of COVID-19 infection.”

Impaired consciousness can occur in up to 37% of patients, due to various mechanisms such as infection and direct brain injury, metabolic-toxic encephalopathy, and demyelinating disease. Encephalitis has not been documented as a result of COVID-19.

Toxic-metabolic encephalopathy can occur due to a number of disorders of metabolic and endocrine function. These include electrolyte and mineral imbalances, kidney disorders, and cytokine storms, hypo or hyperglycemia, and liver dysfunction. Patients who are elderly, ill, or already have symptoms of dementia, or are malnourished, are at higher risk for this condition.

Less common neurological complications include Guillain-Barre syndrome, which is a post-viral acute inflammatory demyelinating disease, and cerebrovascular events, including stroke.

Is COVID-19 Therapy Related to Neurological Manifestations?

Nowadays, many different drugs are used to treat this condition.

Chloroquine and hydroxychloroquine, for example, can cause psychosis, peripheral neuropathy, and the latter can worsen the symptoms of myasthenia gravis. Tocilizumab, an IL-6 blocker, is intended to reduce excessive cytokine release that occurs in severe inflammation. Although admission to CNS is limited, it can sometimes cause headaches and dizziness.

Precautions for COVID-19 Patients with Neurological Conditions

If a patient already has a neurological condition that requires special treatment, they tend to be at higher risk for COVID-19, due to existing lung, heart, or liver conditions, having kidney disease (dialysis), if they are overweight, or at immunosuppressive drugs. Also, it is likely that they may be in nursing homes, where many countries have reported severe outbreaks.

This study concludes: “Doctors must continue to monitor patients closely for neurological diseases. Early detection of neurological deficits can lead to improved clinical outcomes and better treatment algorithms. “

Journal reference:

  • Zubair, A. S. et al. (2020). Neuropathogenesis and Neurological Manifestations of Coronavirus in the Coronavirus Era 2019: Overview. JAMA Neurology. doi: 10.1001 / jamaneurol.2020.2065.


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When is the COVID-19 vaccine ready? | Instant News

The story so far: On April 23, Oxford University began a phase-1 human clinical trial of its vaccine – ChAdOx1 nCoV-19 – against a new coronavirus, SARS-CoV-2. A single dose of vaccine candidates will be given to 1,112 healthy volunteers to study safety, ability to produce an immune response and vaccine efficacy. Oxford University is optimistic about the positive results of vaccine candidates and has planned to get millions of vaccine doses before the end of the year even though the results of the final phase of the trial (phase-3) are awaited. The vaccine candidate was developed by the University Jenner Institute which began trials on humans on April 23 together with the Oxford University Vaccine Group.

How was the vaccine tested constructed?

The vaccine, ChAdOx1 nCoV-19, uses the common cold virus (adenovirus) which causes infection in chimpanzees. Adenovirus has been genetically altered so that it doesn’t grow after being injected. Its construction carries genetic material from new coronaviruses that make spike proteins. Surge proteins are found on the surface of the virus and play an important role in binding specific human receptors found on the cell surface and entering the cell.

By introducing genetic material from protein spikes, vaccine candidates will help the body recognize it and make antibodies against protein spikes. The antibodies produced will help improve the immune response and prevent the virus from entering human cells and causing infection.

Oxford University has used a vaccine made from adenovirus construction for more than 320 people and has found that it is safe and well tolerated. It does cause temporary side effects such as fever, headaches or diseased arms but is otherwise safe.

Has it been tested on animals?

The adenovirus construction has been used by Oxford University researchers to test the safety of the Severe Acute Respiratory Syndrome (SARS) 2002 and the Middle East Respiratory Syndrome (MERS). After the safety of the MERS vaccine was proven in trials conducted in the UK, the trial began in December last year in Saudi Arabia, where MERS outbreaks often occur.

Safety of vaccine candidates was previously tested on six rhesus monkeys.

A single dose protects all six animals for almost a month even when exposed to high levels of the virus, increasing the confidence of researchers.

How is the clinical trial process?

Up to 1,112 healthy volunteers from Oxford, Southampton, London and Bristol have been recruited for phase-1 trials. Volunteers, both men and women between 18-55 years old, are being recruited for the trial. A single dose of vaccine candidates will be given to volunteers. Participants will be randomly assigned to receive vaccine candidates (ChAdOx1 nCoV-19) or ‘control’, the MenACWY vaccine, for comparison.

Oxford University uses the MenACWY vaccine – which protects against four types of meningococcal bacteria – rather than copy control. The participants will not know whether he accepted the vaccine candidate or not. University researchers will also test two vaccine candidate doses given four weeks separately to a small group of 10 volunteers to assess the dose and immune response.

For the control group, why are vaccines for meningococcal bacteria used and not copy?

The MenACWY vaccine is a licensed vaccine given routinely to adolescents in the UK since 2015. The MenACWY vaccine is used as an “active control” vaccine to help understand participant responses to ChAdOx1 nCoV-19. The reason for using this vaccine, rather than copy control, is because researchers hope to see some small side effects of the ChAdOx1 nCoV-19 vaccine such as arm pain, headaches, and fever. Saline does not cause this side effect. If participants only receive this vaccine or copy control, and then develop side effects, they will realize that they have received a new vaccine. It is important for this study, said Oxford University, that participants remain blind to whether they have received the vaccine or not, “such as, if they know, this can affect their health behavior in the community after vaccination, and can lead to bias in research results” .

While all participants will be told how to reduce the risk of infection, it is necessary that participants who receive both the vaccine are exposed to the virus and some are infected. Only thus will it be possible to understand if the vaccinated group remains protected or not compared to the control group. For this purpose, keeping participants in the dark about the vaccine received makes a strong trial.

What is the schedule for the trial?

Phase-1 trials are expected to be completed by the end of May if transmission remains high in the community. Phase-2 trials can be completed in August-September. According to Suresh Jadhav, Executive Director of the Indian Serum Institute Pvt. Ltd., phase-2 and phase-3 trials can be combined if the phase-1 trial results are encouraging.

When will the Pune Serum Institute start making vaccines?

According to Mr. Jadhav, the company will start producing vaccines once phase-3 or phase-2 / phase-3 trials begin. If the last two stages of the experiment are combined they will start producing vaccines at the end of June and be ready with millions of doses by the end of the year. The company is confident that it will produce 60-70 million doses of vaccine by the end of this year. He said, “Because we will start making it when the final phase of the trial begins, we will have millions of vaccine doses ready when the trial ends.”

How much does it cost?

In a tweet on April 30, Oxford University said that they partnered with AstraZeneca to produce and distribute vaccines as quickly as possible. It was said that the vaccine would be available on a “not for profit basis for the duration of the coronavirus pandemic”.

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