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Covid-19 is primarily airborne: Lancet

(Asian News Hub) – A report in The Lancet journal has dismissed the predominant scientific view that SARS-CoV-2, the coronavirus that causes Covid-19, is not an airborne pathogen.

Areport published in the journal The Lancet has dismissed the predominant scientific view that SARS-CoV-2, the coronavirus that causes Covid-19, is not an airborne pathogen. The authors of the report have listed 10 reasons for their claim that “SARS-CoV-2 is transmitted primarily by the airborne route”.

The paper, written by six experts from the UK, the US and Canada, argues that there are “insufficient grounds for concluding that a pathogen is not airborne” while “the totality of scientific evidence indicates otherwise”. The experts called for urgent modification in the Covid-19 safety protocol.

CORONAVIRUS IS AIRBORNE: 10 REASONS CITED BY THE RESEARCHERS

  1. “Superspreading events account for substantial SARS-CoV-2 transmission; indeed, such events may be the pandemic’s primary drivers,” they said. Detailed analyses of human behaviours and interactions, room sizes, ventilation, and other variables, the authors said, are consistent with airborne spread of SARS-CoV-2 and the same cannot be adequately explained by droplets or fomites.
  2. Long-range transmission of SARS-CoV-2 between people in adjacent rooms but never in each other’s presence has been documented in quarantine hotels, the paper said.
  3. The experts argued that from 33 per cent to 59 per cent of all Covid-19 cases could be attributed to asymptomatic or presymptomatic transmission of SARS-CoV-2 from people who are not coughing or sneezing. They said this supported a predominantly airborne mode of transmission.
  4. Transmission of SARS-CoV-2 is higher indoors than outdoors and is substantially reduced by indoor ventilation.
  5. The paper said nosocomial infections (those that originate in a hospital) had been documented even at places where healthcare professionals used personal protective equipment (PPE) designed to protect against droplet but not aerosol exposure.
  6. The experts said viable SARS-CoV-2 has been detected in the air. In laboratory experiments, SARS-CoV-2 stayed infectious in the air for up to 3 hours. They rejected the argument that SARS-CoV-2 was bit cultivated from air arguing that measles and tuberculosis, two primarily airborne diseases, had never been cultivated from room air.
  7. SARS-CoV-2 has been identified in air filters and building ducts in hospitals with COVID-19 patients; such locations could be reached only by aerosols, they said.
  8. The experts cited studies involving infected caged animals that showed transmission of SARS-CoV-2 via an air duct.
  9. Another argument of the experts was that no study to our knowledge provided strong or consistent evidence to refute the hypothesis of airborne SARS-CoV-2 transmission.
  10. Their final argument was that there was limited evidence to support other dominant routes of transmission- i.e. respiratory droplet or fomite.

The claim of the experts, if proven and accepted, could have massive implications on counter-Covid-19 strategy across the world. This may require the people to wear mask even inside their homes, and possibly at all times.

The current understanding is that SARS-CoV-2 spreads through smaller aerosols that stay suspended in air or through fomites, the surfaces where the virus gets deposited, and could be picked by a health person. Gravity pulls down heavier droplets reducing the chances of infection considerably.

But if an infectious virus is mainly airborne, an individual could potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, sneezes, or coughs, the experts said. This changes the way the world should fight coronavirus pandemic.

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CT scan effective tool to detect, determine severity of Covid-19 cases: DAK

(Asian News Hub) – Doctors Association Kashmir (DAK) on Saturday said chest CT scan is an effective tool to detect and determine the severity of Covid-19 cases.

“CT scan helps in diagnosing and predicting the outcome of Covid-19 patients,” said DAK President and influenza expert Dr Nisar ul Hassan.

“More Covid cases are detected with a CT scan of the chest than through RT-PCR,” he said.

Dr Hassan said we see many patients who test negative on RT-PCR test, but show CT features consistent with Covid-19 disease.

 “Many infected patients go unreported as only RT-PCR positive cases are reported. We have a large number of patients who test positive through CT, but are not reported,” he said.

Dr Hassan said RT-PCR, which uses swab for the detection of Covid-19 infection has a sensitivity of 60%-70%. That means more than 30% of positive cases may be missed by the test.

“Another swab test which is now widely used is rapid antigen test. It has a sensitivity of around 50 percent, which raises the possibility of missing more than half of the positive cases,” he said.

 “Low sensitivity of swab tests implies that many patients with Covid-19 infection may not be identified and consequently are not isolated from healthy population. And these individuals will continue to spread the disease in the community,” he added.

“Studies have shown that CT has a greater sensitivity ranging from 86% and 98% for detecting positive cases, while having a lower false negative rate than the lab tests,” Dr Nisar said

“In a study of 1,014 patients published in the Journal Radiology, researchers in china found that 88% of the patients showed chest CT findings indicative of Covid-19, while RT-PCR test detected only 59 percent of cases. Among those with negative swab test results, 75 percent had positive chest CT findings,” he said.

The DAK President said not only is CT useful in identifying Covid cases, it also tells us about the severity of the disease.

“That would guide treatment and help reduce the risk of death in Covid patients and save lives,” he said.

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Scientists have taught bees to smell the coronavirus, can identify a case within seconds

(Asian News Hub) – Scientists in the Netherlands have trained bees to identify COVID-19 through their sense of smell, according to a press release from Wageningen University.

The research was conducted on more than 150 bees in Wageningen University’s bio-veterinary research laboratory.

The scientists trained the bees by giving them a treat – a sugar-water solution – every time they were exposed to the scent of a mink infected with COVID-19. Each time the bees were exposed to a non-infected sample, they wouldn’t get a reward (a process known as Pavlovian conditioning).

Eventually, the bees could identify an infected sample within a few seconds – and would then stick out their tongues like clockwork to collect the sugar water.

Bees aren’t the first animals to detect COVID-19 by scent. Researchers have also trained dogs to distinguish between positive and negative COVID-19 samples from human saliva or sweat with fairly high levels of accuracy. A small German study found that dogs could identify positive COVID-19 samples 94% of the time.

That’s because metabolic changes from the coronavirus make an infected person’s bodily fluids smell slightly different than those of a non-infected person.But researchers still aren’t sure whether animals are the best bet for sniffing out COVID-19 cases outside the lab.

“No one is saying they can replace a PCR machine, but they could be very promising,” Holger Volk, a veterinary neurologist, told Nature.

PCR machines are what lab technicians use to process standard COVID-19 swab tests.

At the very least, certain animals could be useful for identifying COVID-19 in places or countries in which high-tech laboratory equipment is scarce or inaccessible.Wageningen scientists, for instance, are working on a prototype of a machine that could automatically train multiple bees at once, then uses their skills to test for coronavirus aerosols (tiny virus-laden particles) in the surrounding environment.

AGENCY

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Delhi hospital study finds 16 per cent vaccinated individuals tested positive for Covid-19

(Asian News Hub) – A small-scale study on 113 healthcare workers who had received at least one vaccine dose at a private hospital in Delhi found that 18 tested positive for Covid but all except one had mild symptoms.

The study, published in the peer-reviewed journal Diabetes and Metabolic Syndrome: Clinical Research and Reviews on May 3, was conducted on employees of the Fortis Centre of Excellence for Diabetes, 
Metabolic Diseases and Endocrinology in Delhi.

The participants in the study by researchers at Fortis, National Diabetes, Obesity and Cholesterol Foundation, and Diabetes Foundation (India), New Delhi, included doctors, nutritionists, nurses, paramedical workers, and maintenance staff.

Of the 113 in the study, 107 had received the second dose of the vaccine.

Taken in percentage form, the study found that 
breakthrough infections — Covid infection in vaccinated individuals — occurred in 15.9 per cent (18 persons) of the vaccinated individuals and 95 per cent had mild symptoms. Of these, 17 incurred the infection after the second dose and one person. Except one person who required hospitalisation, all others had mild Covid-19 disease, the researchers said.

According to the study, of the breakthrough infections in 18 persons, 17 incurred the infection after the second dose. These 17 had got their second dose after a mean of 34.8 days following the first jab. All were symptomatic with fever and half of them had sore throat and cough.

The study covered 123 employees “ 75 males, 48 females with mean age 42 — 113 of whom were vaccinated. Of them, 28 people had received the 
Covaxin vaccine from Bharat Biotech, and 85 the 
Covishield preventive from the Oxford/AstraZeneca stable. Covishield, Covaxin and Sputnik V are the three Covid-19 vaccines currently approved for use in India. The three vaccines claim efficacy of 81 per cent, 70 per cent, and 92 per cent respectively.

However, Sputnik V has not yet hit the market. The researchers noted that breakthrough infections after adequate vaccinations are a matter of concern but adequate data on these infections is not available. Vaccines have effectiveness risk of getting Covid-19 infections by 70-90 per cent, and also shield from severe infection. It is possible, therefore, some people who are fully vaccinated against Covid-19 may get Covid-19 infection, the authors of the study said.

They explained that unpublished data from India as well as published reports from other parts of the world indicate these infections are occurring but are rare. In addition, it appears that these breakthrough infections are either asymptomatic or mild in nature, the authors added. The authors acknowledged some limitations of their study: its small sample size, and absence of data on obesity and co-morbid diseases which are important determinants of severity of Covid-19. They also did not test asymptomatic infections.

PTI

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