COVID-19 Archives - Page 6 of 20 - Dr Amin Azhari

Physical distance may not be enough to prevent viral aerosol exposure indoors

Eighteen months ago, stickers began to dot the floors of most shops, spaced about six feet apart, indicating the physical distance required to avoid the COVID-19 virus an infected person may shed when breathing or speaking. But is the distance enough to help avoid infectious aerosols?

Not indoors, say researchers in the Penn State Department of Architectural Engineering. The team found that indoor distances of two meters — about six and a half feet — may not be enough to sufficiently prevent transmission of airborne aerosols. Their results were made available online print edition of Sustainable Cities and Society.

The researchers examined three factors: the amount and rate of air ventilated through a space, the indoor airflow pattern associated with different ventilation strategies and the aerosol emission mode of breathing versus talking. They also compared transport of tracer gas, typically employed to test leaks in air-tight systems, and human respiratory aerosols ranging in size from one to 10 micrometers. Aerosols in this range can carry SARS-CoV-2.

Release date: 16 September 2021
Source: Penn State

Diet may affect risk and severity of COVID-19

A healthy plant-based diet was linked to a lower risk of getting COVID-19, and among people with COVID-19, a lower risk of experiencing severe symptoms. There was a synergistic relationship between poor diet and increased socioeconomic deprivation with COVID-19 risk that was higher than the sum of the risk associated with each factor alone.

Although metabolic conditions such as obesity and type 2 diabetes have been linked to an increased risk of COVID-19, as well as an increased risk of experiencing serious symptoms once infected, the impact of diet on these risks is unknown. In a recent study led by researchers at Massachusetts General Hospital (MGH) and published in Gut, people whose diets were based on healthy plant-based foods had lower risks on both counts. The beneficial effects of diet on COVID-19 risk seemed especially relevant in individuals living in areas of high socioeconomic deprivation.

For the study, Merino and his colleagues examined data on 592,571 participants of the smartphone-based COVID-19 Symptom Study. Participants lived in the UK and the US, and they were recruited from March 24, 2020 and followed until December 2, 2020. At the start of the study, participants completed a questionnaire that asked about their dietary habits before the pandemic. Diet quality was assessed using a healthful Plant-BasedDiet Score that emphasises healthy plant foods such as fruits and vegetables.

During follow-up, 31,831 participants developed COVID-19. Compared with individuals in the lowest quartile of the diet score, those in the highest quartile had a 9% lower risk of developing COVID-19 and a 41% lower risk of developing severe COVID-19.

Release date: 08 September 2021
Source: Massachusetts General Hospital

Double vaccination halves risk of Long COVID

The study, published in The Lancet Infectious Diseases, found that in the unlikely event of catching COVID-19 after being double vaccinated, the risk of Long COVID was reduced by almost half. There were also fewer hospitalisations (73% less likely) and lower burden of acute symptoms (31% less likely) among those fully vaccinated. The nature of the most common symptoms were similar to unvaccinated adults – e.g. anosmia,(loss of smell) cough, fever, headaches, and fatigue. All these symptoms were milder and less frequently reported by people who were vaccinated, and they were half as likely to get multiple symptoms in the first week of illness. Sneezing was the only symptom which was more commonly reported in vaccinated people with COVID-19.

However, people living in most deprived areas were at greater risk of infection after a single vaccination. While age on its own was not a risk factor, individuals who had health conditions that limited their independence – such as frailty – were up to two times more likely to contract COVID-19 infection after vaccination, and of getting sick.

The findings demonstrate the need to target at-risk groups. Frail adults have already been shown to be disproportionately affected by COVID-19. The research team suggests strategies such as a timely booster programme, targeted infection control measures and more research into the immune response to vaccination in this group could help address the issue.

Release date: 01 September 2021
Source: King’s College London

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Prior exposure to common cold coronaviruses enhances immune response to SARS-CoV-2

Researchers from Charité – Universitätsmedizin Berlin, the Berlin Institute of Health at Charité (BIH) and the Max Planck Institute for Molecular Genetics (MPIMG) have shown that certain immune cells, which are found in people previously exposed to common cold coronaviruses, enhance the body’s immune response to SARS-CoV-2, both during natural infection and following vaccination. The researchers, whose work has been published in Science, also report that this ‘cross-reactive immunity’ decreases with age. This phenomenon may help to explain why older people are more susceptible to severe disease and why their vaccine-induced immunity is often weaker than that of young people.

Last year, researchers from Charité and the MPIMG made a surprising discovery. They were the first to report that individuals with no prior exposure to SARS-CoV-2 nonetheless had immunological memory cells capable of recognizing this novel virus. The researchers concluded that these ‘T helper cells’ must have been generated to deal with mostly harmless common cold coronaviruses and that, thanks to the structural similarities between coronaviruses (in particular the characteristic spike protein found on their outer surface), these T helper cells will also attack the novel coronavirus. This ‘cross reactivity’ hypothesis has since been confirmed by a range of studies.

Release date: 31 August 2021
Source: Charité – Universitätsmedizin Berlin

The combination of mask wearing and keeping windows open is best for reducing Covid-19 risk in cars

As the country prepares to live in a post-Covid-19 world and car travel – including taxi and car-sharing services that mix households – returns to normal, new research from the University of Surrey has confirmed that keeping car windows open to draw in fresh air is key to reducing the risk of contracting the virus in vehicle environments – but there are trade-offs.

In a paper published by Environment International, Surrey’s renowned Global Centre for Clean Air Research (GCARE) explored what motorists must consider to make sure their in-car environments are as Covid-secure as possible.

The GCARE team used sensors to monitor pollution particles concentration, map how those particles varied during different settings in the vehicle and evaluate exposure dose per km of PM2.5 for three different ventilation settings (open window, air conditioning using fresh air, and air conditioning using air recirculation). The team also used sensors to monitor CO2 emission – a proxy used in the experiment for Covid-19.

The GCARE researchers found that maintaining a continuous intake of fresh air by keeping the windows open – while also wearing a mask — is the best way to guard against the transmission of Covid-19 — but this increases occupants’ exposure to toxic air pollution particles.

Motorists face a dilemma, since guarding against air pollution by keeping windows closed in turn aggravates the risk from Covid-19: the study found that the probability of Covid-19 transmission rate increased by 28.5 per cent when windows are closed and air recirculation is switched on.

For the best chance of remaining safer from both Covid-19 and external air pollution, the GCARE team found that keeping the windows closed — which mitigates air pollution particles — while running air conditioning on ambient mode (drawing in fresh air from outside) to minimize exposure to Covid-19, is the optimal balance.

Release date: 28 August 2021
Source: University of Surrey

Public Health

Symptomatic COVID patients are more contagious

UGA study identifies link between case severity and infectiousness. Individuals with COVID-19 are most likely to spread the virus to close contacts two days before the onset of symptoms to three days after symptoms appear, and the risk of transmission is highest when patients had mild or moderate disease severity, according to a new study by researchers at the University of Georgia.

The study, which was published in JAMA Internal Medicine, supports the idea that if a person with COVID-19 is sicker, they are more contagious compared to asymptomatic cases.

Release date: 26 August 2021
Source: University of Georgia

Gender Differences in Fear and Risk Perception During the COVID-19 Pandemic

The COVID-19 pandemic has led many people to suffer from emotional distress. Previous studies suggest that women process and express affective experiences, such as fear, with a greater intensity compared to men. We administered an online survey to a sample of participants in the United States that measures fear of COVID-19, perceptions about health and financial risks, and preventative measures taken. Despite the empirical fact that men are more likely to experience adverse health consequences from COVID-19, women report greater fear and more negative expectations about health-related consequences of COVID-19 than men. However, women are more optimistic than men regarding the financial consequences of the pandemic. Women also report more negative emotional experiences generally during the pandemic, particularly in situations where other people or the government take actions that make matters worse. Though women report taking more preventative measures than men in response to the pandemic, gender differences in behavior are reduced after controlling for fear. These results shed light on how differences in emotional experiences of the pandemic may inform policy interventions. Frontiers in Psychology

Release date: 5 August 2021
Source: PubMed

Covid-19

Detection of SARS-CoV-2-Specific IgA in the Human Milk of COVID-19 Vaccinated Lactating Health Care Workers

SARS-CoV-2 IgA is secreted in human breast milk after vaccination. These suggest the potential protection to nursing infants and may show influence in vaccination strategies.

In 2019, a deadly virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for coronavirus disease 2019 (COVID-19), emerged. In December 2020, two mRNA-based COVID-19 vaccines were approved for use in the United States, which provide immunity to those receiving the vaccine. Maternally derived antibodies are a key element of infants’ immunity. Certain vaccines given to pregnant and lactating mothers provide immunity to infants through transmission across the placenta, umbilical cord (IgG), and human milk (IgA). Human milk produced by mothers with a history of COVID-19 infection contains SARS-CoV-2 IgA and IgG. The purpose of this study is to determine whether SARS-CoV-2-specific immunoglobulins are found in human milk after the COVID-19 vaccination, and to characterize the types of immunoglobulins present.

Results show that the mRNA-based COVID-19 vaccines induce SARS-CoV-2-specific IgA and IgG secretion in human milk. Further studies are needed to determine the duration of this immune response, its capacity to neutralize the COVID-19 virus, the transfer of passive immunity to breastfeeding infants, and the potential therapeutic use of human milk IgA to combat SARS-CoV-2 infections and COVID-19.

Release date: 20 August 2021
Source: University of Florida

Antibodies elicited by COVID-19 vaccination effective against delta variant

Findings help explain why vaccinated people at low risk during delta surge.

Despite causing a surge in infections this summer that has resulted in thousands of hospitalizations and deaths, the delta variant of the virus that causes COVID-19 is not particularly good at evading the antibodies generated by vaccination, according to a study by researchers at Washington University School of Medicine in St. Louis.

The researchers analyzed a panel of antibodies generated by people in response to the Pfizer COVID-19 vaccine and found that delta was unable to evade all but one of the antibodies they tested. Other variants of concern, such as beta, avoided recognition and neutralization by several of the antibodies.

The findings, published Aug. 16 in the journal Immunity, help explain why vaccinated people have largely escaped the worst of the delta surge.

Release date: 17 August 2021
Source: Washington University School of Medicine

Neurologic disorders

Problems in thinking and attention linked to COVID-19 infection

Evidence of cognitive deficits in people who have recovered from COVID-19 has been discovered in a new study of over 80,000 individuals.

The research found that those with more severe COVID-19 symptoms scored lower on an online series of tests, with performance on reasoning and problem-solving tasks being most affected. Further analysis of the data indicated that those who received mechanical ventilation to help them breathe whilst in hospital had the greatest impairment on cognitive tasks.

Out of the 81,337 who provided complete data, 12,689 people suspected they had COVID-19. Participants reported a range of severity of illness, with many experiencing respiratory symptoms whilst still being able to stay at home (3,559 participants). Nearly 200 were hospitalised (192 participants) and about a quarter of these (44 participants) required mechanical ventilation.

The time since illness onset was around 1-6 months, meaning the study could not draw any definitive conclusions about whether these effects on cognition were long-lasting.

Published in the journal EClinicalMedicine, the research was a collaboration between King’s College London, Imperial College London and Cambridge University.

Release date: 11 August 2021
Source: King’s College London

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