Tag: covid transmission

Categories : COVIDTags :

SA Experts Confirm That COVID Variant is More Contagious

On By ModernMedia

A panel of South African experts confirmed on Monday that the SA strain of COVID is 50% more transmissible than previous strains.

Collecting data from the main infection clusters around the country, the experts came to the conclusion that while more contagious, the new variant is not more lethal. 

“There is no evidence the new COVID variant is more severe than the original variant,” said epidemiologist Professor Salim Abdool Karim, co-chair of the Ministry of Health’s scientific committee.

However, the SA healthy system has been strained by the sheer number of cases. Concerns over more transmissible variants have prompted the UK government to switch to administering the first dose of two-dose vaccines such as the one from Pfizer, and leaving an extended period before a second dose is administered, even though protection will wane over time.

Another panel member, Dr Waasila Jassat, said that although hospital admissions had increased, the overall death rate had not, supporting the case for the variant not being more lethal.

The spread of the variant in December prompted the government to reinstate its lockdown. It also resulted in many countries banning flights from South Africa in a bid to stem the variant. Prof Karim said that it was not yet known if current vaccines would protect against the SA variant, although studies were underway.

Another panel member, virologist Professor Alex Sigal stated: “The world has underestimated this virus.” He added that it was evolving and adapting to humans.

The experts also urged that it should not be referred to as the “South African variant”. The variant could have turned up anywhere in the world, and it was only thanks to the country’s excellent genomic surveillance that it was picked up at all, they said.

Source: Medical Xpress

Categories : UncategorizedTags :

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

Categories : COVIDTags :

Effectiveness of COVID Government Interventions Compared

On By ModernMedia

Currently, the most widely used tool to deal with the spread of COVID are non-pharmaceutical interventions (NPIs), which involve measures such as social distancing. In the face of the sudden emergency of the COVID pandemic, governments around the world implemented a wide range of NPIs, some based on scientific advice and some not. The effectiveness of these government interventions is compared in a new study.

In order to evaluate the effectiveness of these responses, researchers studied government interventions across 79 countries and territories. Each item was ranked, making a comprehensive dataset of 6068 interventions and compared to the reproduction number, Rt. They were analysed with four computational methods, including machine learning.

The study found that the most effective interventions were those that restricted movement such as travel restrictions and lockdowns, as well as social distancing. Cancellations of gathering also seemed to be effective. The least effective were appeals for international aid, tracking and tracing, disinfecting surfaces had the least impact.

Interventions also had differing effectiveness depending on what stage of the pandemic they were implemented in.

The most consistently effective intervention across all locations was contact tracing and quarantine.

Source: News-Medical.Net

Categories : COVIDTags :

COVID and Vaping Lung Injuries can be Confused

On By ModernMedia

Three recent case studies show that breathing problems in teens could be a result of vaping or COVID, according to a UC Davis Health paediatric team.

Known as e-cigarette, or vaping, product use-associated lung injury (EVALI), it is present in large numbers. As of February 2020, 2758 cases of EVALI were hospitalised, with 64 deaths in the United States, and over half of those hospitalised were under 25 years old.

“EVALI and COVID-19 share many symptoms but have very different treatment plans,” said lead author Kiran Nandalike, associate professor of paediatrics. “For this reason, providers caring for pediatric patients with unexplained respiratory failure should consider EVALI and ask for relevant smoking/vaping history.”

EVALI and COVID patients often present with fever, cough, nausea, abdominal pain and diarrhoea. Bilateral ground glass opacities are seen in chest imaging in both conditions.

Adolescents often use vaping with marijuana obtained through friends, family and unlicenced dealers, with products often containing vitamin E acetate, an additive which is strongly associated with lung injury. Isolation and stress as a result of the COVID pandemic increased usage.

In the case studies, all of the patients had fever, nausea and cough, as well as a high heart rate, rapid breathing and low blood oxygen levels. Laboratory results showed higher white blood cells (WBC) count and elevated inflammation, pointing to COVID inflammation. Chest imaging revealed nonspecific ground glass opacities. Despite all other findings indicating COVID, SARS-CoV-2 testing was negative. The patients were successfully treated with steroids, a potentially life-saving treatment for EVALI.

“To help reduce risk of EVALI recurrence, providers would recommend vaping cessation counseling to patients and close outpatient monitoring,” advised Nandalike.

Source: Medical Xpress

Categories : COVIDTags :

COVID Most Infectious Early On, Says New Review

On By ModernMedia

According to a meta-analysis of COVID research published in The Lancet, individuals with COVID are most infectious early on.

In a meta-analysis of 79 studies from around the world, they examined viral load dynamics, duration of viral RNA shedding, and viable virus shedding for SARS-CoV-2, and for comparison, 8 studies on MERS-CoV and 11 on SARS-CoV. The study only looked at symptomatic individuals.

For SARS-CoV-2, the average duration of viral RNA shedding was 17 days in the upper respiratory tract and 14.6 days in the lower respiratory tract. Similar durations were found for stool (17.2 days) and serum samples (16.6 days). 

The maximum duration of viral RNA shedding was 83 days in the upper respiratory tract, 59 days in the lower respiratory tract and 126 days in stools.  No role could be discerned for faecal shedding. Average shedding duration was positively correlated with age. No studies detected live virus after 9 days.

The viral load in the upper respiratory tract reached a peak in the first week of illness, which was shorter than SARS-CoV (peaking at days 10-14) and MERS-CoV (days 7-10). Most studies indicated faster viral load clearing in asymptomatic versus symptomatic SARS-CoV-2 carriers.

In view of these findings, the researchers suggest that repeat testing may not be necessary for patients no longer deemed infectious, and that isolation could be set for 10 days after the onset of symptoms.

The researchers concluded that early containment was key in fighting the spread of COVID, especially with regard to acting on atypical symptoms that might appear before other symptoms. Still, this could prove challenging to effect in practice. 

Source: The Lancet

Categories : COVIDTags :

Controversial Study: Cloth Masks Don’t Prevent Catching COVID

On By ModernMedia

In a controversial result, researchers in Denmark have shown real-world evidence that masks do not protect against becoming infected with COVID.

4860 participants completed the study in Denmark, which at the time had a 2% infection rate. Half received surgical masks and were told to wear them outside while the other half were told not to wear masks. The researchers had hoped to see the masks halving the infection rate among wearers, but 1.8% of mask wearers became infected with COVID vs 2.1% of non-mask wearers.

“Our study gives an indication of how much you gain from wearing a mask,” said lead author Dr Henning Bundgaard, a cardiologist at the University of Copenhagen. “Not a lot.”

The results were met with scepticism by some, and noted that the lower prevalence of COVID in Denmark at the time made differences hard to detect.

Dr Thomas Frieden, chief executive of Resolve to Save Lives, an advocacy group, and former director of the CDC outlined the limitations of the study, saying, “There is absolutely no doubt that masks work as source control. The question this study was designed to answer is: Do they work as personal protection?” Frieden said that the answer to those questions lay in the amount of virus exposure and the nature of the masks involved.

“An N95 mask is better than a surgical mask,” he said. “A surgical mask is better than most cloth masks. A cloth mask is better than nothing.”

Dr Christine Laine, editor in chief of the Annals of Internal Medicine, characterised the evidence that masks were protective of wearers as weak.

“These studies cannot differentiate between source control and personal protection of the mask wearer,” she said. 

She added that the new study reinforced the need for other methods, such as social distancing. Masks “are not a magic bullet,” she said. “There are people who say, ‘I’m fine, I’m wearing a mask.’ They need to realise they are not invulnerable to infection.”

Source: Japan Times

Categories : COVIDTags :

COVID Cough Droplets Can Travel up to 6.6m

On By ModernMedia

Researchers in Singapore have employed fluid physics to add to the growing body of research surrounding the airborne transmission of the SARS-CoV-2 virus. 

“In addition to wearing a mask, we found social distancing to be generally effective, as droplet deposition is shown to be reduced on a person who is at least one metre from the cough,” said study author Fong Yew Leong.

The researchers found that the results were highly dependent on ambient air characteristics, such as temperature and humidity, as well as assumptions about the viability of the virus

“An evaporating droplet retains the non-volatile viral content, so the viral loading is effectively increased,” said author Hongying Li.

Source: IOL