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N95 masks are a must as COVID-19 spreads via airborne transmission too: AIIMS Chief

(Asian News Hub) – AIIMS chief Randeep Guleria said on Sunday that the fact that coronavirus can be transmitted through aerosols makes it more contagious since these are much smaller and lighter particles than droplets.

Because of their small size, aerosols can hang in the air and travel a distance of even up to 10 metres. He emphasised the need to use N95 masks for staying safe from the deadly disease.

Until now the emphasis has been that coronavirus is transmitted predominantly through droplets while coughing or sneezing. However, a study published in the reputed British medical journal The Lancet this week concludes that coronavirus spreads predominantly through airborne transmission.

Since the disease is airborne a social distance of 3 metres is not enough to keep you safe and you can get infected even after a person has left the immediate vicinity as the virus could be lingering in the air.

Speaking on NDTV, Dr Guleria said the debate of droplets versus aerosols has been going on for the last eight or nine months but the fact that the disease can be transmitted through aerosols which can travel through longer distances in the air makes the disease more contagious.

He said the virus from an infected person can linger in the air for much longer when it is carried in aerosols as these are much smaller particles than droplets which drop to the ground in the immediate vicinity.
Thus while a social distance of 3 metres is enough in the case of droplets, when it comes to aerosols the distance which the virus can travel could go up to 10 metres.

He said it is essential, therefore, to keep all rooms well ventilated so that aerosols are not left hanging in the air. The doors and windows of a room should be kept open, he added.

Guleria also said that meetings should not be held in closed rooms as if there is an infected person he can leave aerosols in the air. These are left floating in the air even after the person has left.

The AIIMS chief said it was also important to wear N95 masks as these can effectively stop the virus. But he emphasised that the mask should be worn properly so that it completely seals the nose and mouth. One must ensure that no air enters from the sides of the mask. N95 masks are a must.

He also said that in the case of a surgical mask or cloth masks, which are not as effective as N95 masks, wearing two masks helps as this provides a double layer of protection.

But if it is an N95 mask worn properly, then one mask is enough, he added.

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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.

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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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