Covid-19 Archives - Page 4 of 22 - Dr Amin Azhari

Immune memory less durable after severe COVID-19

Infection-fighting B cells retain better memory of the coronavirus spike protein in University Hospital patients who recover from less-severe cases of COVID-19 than in those recovering from severe COVID-19, a new study suggests. Findings by scientists from The University of Texas Health Science Center at San Antonio were published in the journal PLOS ONE .

The study focused on memory B cells that react against the SARS-CoV-2 spike protein. Blood samples were analyzed one month after symptom onset and five months post-onset. After one month, a significant proportion of spike-specific B cells were active.

However, samples from eight individuals who recovered from less-severe disease showed increased expression of markers associated with durable B cell memory as compared to individuals who recovered from severe disease, the authors wrote. The markers include T-bet and FcRL5.

T-bet-positive, spike-specific B cells nearly disappeared from the blood samples five months post-symptom onset, the authors noted. Overall, a more dysfunctional B cell response is seen in severe disease cases, they wrote.

Release date: 23 December 2021
Source: University of Texas Health Science Center at San Antonio

Metabolic syndrome increases risk of respiratory distress, death for hospitalized COVID-19 patients

Patients hospitalized with COVID-19 who had a combination of high blood pressure, obesity, diabetes or other conditions associated with metabolic syndrome were at much higher risk of acute respiratory distress syndrome (ARDS) and death, according to an international study published in the medical journal JAMA Network Open.

The risk for developing ARDS, a life-threatening lung condition that causes low blood oxygen, grew progressively higher with each additional metabolic syndrome criteria present. The study, one of the largest to examine the link between metabolic syndrome and outcomes for COVID-19, examined records of more than 46,000 patients admitted in 181 hospitals across 26 countries.

Researchers from Tulane University, the Society of Critical Care Medicine and Mayo Clinic followed outcomes for patients hospitalized between mid-February 2020 to mid-February 2021 in the Discovery VIRUS: COVID-19 Registry. Researchers compared 5,069 patients (17.5%) with metabolic syndrome with 23,971 control patients (82.5%) without metabolic syndrome. They defined metabolic syndrome as having more than three of the following criteria: obesity, pre-diabetes or diabetes, hypertension and high cholesterol.

Patients with metabolic syndrome were 36% more likely to develop ARDS, almost 20% more likely to die in the hospital, more than 30% more likely to be admitted to an ICU and 45% more likely to require mechanical ventilation. Researchers calculated these risks after adjusting for race, age, sex, ethnicity, other comorbid conditions and hospital case volume.

Overall, slightly more than 20% of the patients with metabolic syndrome died in the hospital, 20% developed ARDS and almost half were admitted to the ICU. Approximately 16% of those without metabolic syndrome died, 12% developed ARDS and nearly 36% were admitted to the ICU.

Metabolic syndrome was significantly more common among patients with COVID-19 admitted to U.S. hospitals (18.8%) than those admitted to non-U.S. hospitals (8%). According to the Centers for Disease Control, more than a third of adults in the U.S. meet the criteria for metabolic syndrome, with some regions having a metabolic syndrome prevalence greater than 40%.

Release date: 22 December 2021
Source: Tulane University

Public Health, Public Health, Public Health, Public Health, Public Health, Public Health, Public Health, Public Health

Drug could more effectively treat patients hospitalised with COVID-19 pneumonia

A proof-of-concept trial led by the University of Birmingham and University Hospitals Birmingham NHS Foundation Trust has identified a drug that may benefit some patients hospitalised with COVID-19 pneumonia.

An antibody already in late-stage trials to treat rheumatoid arthritis, namilumab targets a ‘cytokine’ which is naturally secreted by immune cells in the body but, in uncontrolled levels, is believed to be a key driver of the excessive and dangerous lung inflammation seen in COVID-19 patients.

The trial, carried out in collaboration with the University of Oxford and funded by the Medical Research Council and carried out between June 2020 and February 2021, involved patients aged over 16 with COVID-19 pneumonia either being treated on a ward or Intensive Care Unit (ICU) at nine NHS hospitals across the UK.

The study, published in The Lancet Respiratory Medicine, involved 54 patients receiving ‘usual care’ (steroids and oxygen or ventilation, depending on the severity of disease) and 57 patients given usual care as well as a single intravenous dose of 150mg of namilumab.

As well as COVID-19 pneumonia, all study participants had CRP levels greater than 40mg/l. The researchers compared the probability of the reduction of levels of CRP in patients. Compared to usual care alone, the researchers found there was a 97% probability of CRP being reduced over time in those given namilumab when compared with usual care alone.

The patients were monitored, and after 28 days the study also showed there were fewer deaths and more discharges from hospital or ICU in those who had been given namilumab compared to those receiving usual care alone.

By day 28, 78% (43) of the patients receiving namilumab were discharged from hospital or ICU, compared to 61% (33) of the patients given usual care. In the namilumab group, 11% (6) were still in hospital by day 28, compared to 20% (11) in the usual care group. Of those in the namilumab group, 11% (6) patients died compared to 19% (10) who died in the usual care group by day 28.

The team calculated the differences between the two cohorts in overall probability of those being discharged from ICU or a ward at 28 days. Of those on a ward, the probability of discharge at day 28 was 64% in the usual care cohort, compared to 77% in the Namilumab cohort. Of those in ICU, probability of discharge at day 28 was 47% in the usual care group, compared to 66% in the Namilumab cohort.

Release date: 17 December 2021
Source: University of Birmingham

Neurologic disorders

SARS-CoV-2 protein interacts with Parkinson’s protein, promotes amyloid formation

Case reports of relatively young COVID-19 patients who developed Parkinson’s disease within weeks of contracting the virus have led scientists to wonder if there could be a link between the two conditions. Now, researchers reporting in ACS Chemical Neuroscience have shown that, at least in the test tube, the SARS-CoV-2 N-protein interacts with a neuronal protein called α-synuclein and speeds the formation of amyloid fibrils, pathological protein bundles that have been implicated in Parkinson’s disease.

In addition to respiratory symptoms, SARS-CoV-2 can cause neurological problems, such as loss of smell, headaches and “brain fog.” However, whether these symptoms are caused by the virus entering the brain, or whether the symptoms are instead caused by chemical signals released in the brain by the immune system in response to the virus, is still controversial. In Parkinson’s disease, a protein called α-synuclein forms abnormal amyloid fibrils, leading to the death of dopamine-producing neurons in the brain. Interestingly, loss of smell is a common premotor symptom in Parkinson’s disease. This fact, as well as case reports of Parkinson’s in COVID-19 patients, made Christian Blum, Mireille Claessens and colleagues wonder whether protein components of SARS-CoV-2 could trigger the aggregation of α-synuclein into amyloid. They chose to study the two most abundant proteins of the virus: the spike (S-) protein that helps SARS-CoV-2 enter cells, and the nucleocapsid (N-) protein that encapsulates the RNA genome inside the virus.

Release date: 14 December 2021
Source: American Chemical Society

Vaccines and previous infection could offer some “stronger than basic” protection to Omicron

One of the earliest, peer-reviewed studies looking into the Omicron variant of COVID-19 suggests that people previously infected with COVID, and those vaccinated, will have some, “stronger than basic” defense against this new strain of concern.

However, the test tube (or ‘in-vitro’, scientifically) samples of Omicron examined in this new research do show it “exceeds” all other variants in its potential capability to evade the protection gained from previous infection or vaccination.

Published inEmerging Microbes & Infections, the findings also suggest that although a third-dose enhancement strategy can “significantly boost immunity”, the protection from Omicron “may be compromised” – but more research is needed to better understand this.

Reporting on this very early study, lead author Youchun Wang, Senior Research Fellow from the National Institutes for Food and Drug Control in China, says their results support recent findings in South Africa which highlight Omicron was “easy to evade immunity”.

“We found the large number of mutations of the Omicron variant did cause significant changes of neutralization sensitivity against people who had already had COVID,” Wang says.

Release date: 12 December 2021
Source: Taylor & Francis Group

Public Health

Natural infection and vaccination together provide maximum protection against COVID variants

A combination of vaccination and naturally acquired infection appears to boost the production of maximally potent antibodies against the COVID-19 virus, new UCLA research finds.

The findings, published in the peer-reviewed journal mBio, raise the possibility that vaccine boosters may be equally effective in improving antibodies’ ability to target multiple variants of the virus, including the delta variant, which is now the predominant strain, and the recently detected omicron variant. (The study was conducted prior to the emergence of delta and omicron, but Dr. Otto Yang, the study’s senior author, said the results could potentially apply to those and other new variants.)

The researchers compared blood antibodies in 15 vaccinated people who had not been previously infected with SARS-CoV-2, the virus that causes COVID-19, with infection-induced antibodies in 10 people who were recently infected with SARS-CoV-2 but not yet vaccinated. Several months later, the 10 participants in the latter group were vaccinated, and the researchers then reanalyzed their antibodies. Most people in both of the groups had received the Pfizer–BioNTech or Moderna two-dose vaccines.

The scientists evaluated how antibodies acted against a panel of spike proteins with various common mutations in the receptor-binding domain, which is the target for antibodies that help neutralize the virus by blocking it from binding to cells.

They found that the receptor-binding domain mutations reduced the potency of antibodies acquired both by either natural infection or vaccination alone, to about the same degree in both groups of people. When previously infected people were vaccinated about a year after natural infection, however, their antibodies’ potency was maximized to a point that they recognized all of the COVID-19 variants the scientists tested.

Release date: 07 December 2021
Source: UCLA Health Sciences

Nutrition in rehabilitation

COVID-19 Delta variant may have increased ability to evade vaccine-induced immunity

Vaccines are effective in decreasing hospitalization and deaths from COVID-19 infection but the emergence of viral variants of concern may diminish their efficacy. A study publishing in PLOS Pathogens by Emma Thomson, Brian Willett, and colleagues at the MRC-University of Glasgow Centre for Virus Research, United Kingdom and colleagues suggests that COVID-19 Delta variant may be more successful at evading the protective response of vaccines.

Mutations change the shape of the COVID-19 spike protein, preventing antibody recognition and enabling the virus to escape vaccine-induced immunity; however, the extent to which vaccine recipients are immune from the Delta variant is unknown. To quantify the capacity of different variants (Alpha, Beta and Delta) to evade protective immune response in vaccines, researchers analyzed serum samples collected from healthy people who had received either the Pfizer or Astra Zeneca vaccine. 156 people had received two doses and 50 people had received one dose. They exposed SARS-CoV-2 proteins in a virus model system to sera from vaccinated people and observed the antibody response, measuring how effectively antibodies prevented each variant from infecting cells (virus neutralization).

Release date: 02 December 2021
Source: EurekAlert

Extent of healthcare avoidance during COVID-19

One in five individuals avoided healthcare during lockdown in the COVID-19 pandemic, often for potentially urgent symptoms, according to a new study publishing in PLOS Medicine by Silvan Licher of Erasmus University Medical Center Rotterdam, the Netherlands, and colleagues.

During the COVID-19 pandemic, consultations in both primary and specialist care declined compared to pre-pandemic levels. It is unclear to what extent healthcare avoidance by the general population contributed to these declines. In the new study, researchers sent out a paper questionnaire to 8,732 participants of the Rotterdam Study, a cohort study designed to investigate chronic diseases in mid to late-life, covering several COVID-19 related topics, including healthcare avoidance. 73% of participants responded between April and July 2020 and the final population for the study was 5,656 individuals residing in the same district in Rotterdam, the Netherlands.

About one in five (20.2%) of participants reported having avoided healthcare during the pandemic. Of those, 414 participants (36.3% of avoiders) reported symptoms that potentially warranted urgent medical attention, including limb weakness (13.6%), palpitations (10.8%) and chest pain (10.2%). However, there was no data available on the severity of symptoms. Groups most likely to have avoided healthcare included females (adjusted odds ratio (OR) 1.58, 95% confidence interval (CI) 1.38-1.82), those with poor self-appreciated health (per level decrease 2.00, 95% CI 1.80‑2.22), and those with high levels of depression (per point increase 1.13, 95% CI 1.11-1.14) and anxiety (per point increase 1.16, 95% CI 1.14-1.18). Lower educational level, older age, unemployment, smoking and concern about contracting COVID-19 were also associated with healthcare avoidance.

Release date: 23 November 2021
Source: EurekAlert

Plant-derived antiviral drug is effective in blocking highly infectious SARS-CoV-2 Delta variant

A plant-based antiviral treatment for Covid-19, recently discovered by scientists at the University of Nottingham, has been found to be just as effective at treating all variants of the virus SARS-CoV-2, even the highly infectious Delta variant.

The struggle to control the Covid-19 pandemic is made more difficult by the continual emergence of virulent SARS-CoV-2 variants, which are either more infectious, cause more severe infection, or both.

In a new study published in Virulence, a group of scientists, led by Professor Kin-Chow Chang from the School of Veterinary Medicine and Science at the University, found that the Delta variant, compared with other recent variants, showed the highest ability to multiply in cells, and was most able to directly spread to neighbouring cells. In co-infections with two different SARS-CoV-2 variants, the Delta variant also boosted the multiplication of its co-infected partners.

The study also showed that a novel natural antiviral drug called thapsigargin (TG), recently discovered by the same group of scientists to block other viruses, including the original SARS-CoV-2, was just as effective at treating all of the newer SARS-CoV-2 variants, including the Delta variant.

In their previous studies* the team showed that the plant-derived antiviral, at small doses, triggers a highly effective broad-spectrum host-centred antiviral innate immune response against three major types of human respiratory viruses, including SARS-CoV-2.

In this latest study, the team set out to find out how well the emergent Alpha, Beta and Delta variants of SARS-CoV-2 are able to multiply in cells relative to each other as single variant infections and in co-infections- where cells are infected with two variants at the same time. The team also wanted to know just how effective TG was at blocking these emergent variants.

Our new study has given us better insights into the dominance of the Delta variant. Even though we have shown that this variant is clearly the most infectious and promotes production of other variants in co-infections, we are pleased to have shown that TG is just as effective against all of them. Together, these results point to the antiviral potential of TG as a post-exposure prophylactic and an active therapeutic agent.” Professor Kin Chow Chang, lead author of the study

Release date: 19 November 2021
Source: University of Nottingham

Unborn babies could contract Covid-19 finds study, but it would be uncommon

Unborn babies could contract Covid 19 finds study - اثر ویروس کرونا بر جنین

An unborn baby could become infected with Covid-19 if their gut is exposed to the SARS-CoV-2 virus, finds a new study led by UCL researchers with Great Ormond Street Hospital for Children and the NIHR Great Ormond Street Biomedical Research Centre.

Although the study did not look specifically at mothers with Covid-19 and whether their infection was transmitted to an unborn baby, it found that certain fetal organs, such as the intestine, are more susceptible to infection than others.

However, researchers say, that opportunities for the Covid-19 virus infecting the fetus are extremely limited, as the placenta acts as a highly effective and protective shield, and evidence suggests fetal infection, known as vertical transmission, is extremely uncommon.

For the study, published in BJOG: An International Journal of Obstetrics & Gynaecology, researchers set out to understand how newborn babies could have developed Covid-19 antibodies, as has been reported in a small number of cases.

Specifically, they wanted to know if and how the virus could be passed from an infected mother to the unborn fetus.

To answer this question, researchers examined various fetal organs and placenta tissue to see if there was any presence of the cell surface protein receptors, ACE2 and TMPRSS2. These two receptors sit on the outside of cells and both are needed for the SARS-Cov-2 virus to infect and spread.

Researchers found the only fetal organs* to feature both the ACE2 and TMPRSS2 were the intestines (gut) and the kidney; however the fetal kidney is anatomically protected from exposure to the virus and is therefore less at risk of infection.

Therefore, the team concluded that the SARS-CoV-2 virus could only infect the fetus via the gut and through fetal swallowing of amniotic fluid, which the unborn baby does naturally for nutrients.

After birth ACE2 and TMPRSS2 receptors are known to be present in combination on the surface of cells in the human intestine as well as the lung. The gut and lung are suspected to be the main routes for Covid-19 infection, but in younger children, the intestine appears to be most important for virus infection.

Release date: 19 November 2021
Source: University College London