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Tuesday, June 22, 2021

Bengaluru staring at new variant of Covid-19, fear medics; scientists say no evidence

Phenomena of deaths occurring among a sizable number of persons due to lung failure, despite negative reports, has raised the concerns of a section of doctors.

Written by Johnson T A | Bengaluru |
Updated: May 6, 2021 7:04:31 am
Covid-19A health worker checks a Covid patient on oxygen support at a hospital, during the second wave of the coronavirus pandemic in Bengaluru (PTI)

Last week, shortly after a 52-year-old patient died at the Victoria Hospital in Bengaluru, a 750-bed government Covid-19 treatment facility in Bengaluru, a doctor in-charge of emergency care at the hospital tried to calm down angry relatives of the patient who could not fathom how someone they spoke to the previous night had died in the morning.

The doctor told the relatives of the patient that the hospital was witnessing many patients suffering from severe lung damage caused by the Coronavirus — despite RT-PCR tests showing up a negative report for the infection. The doctor said medical professionals are now suspecting the involvement of a new Covid-19 variant in these cases.

The phenomena of deaths occurring among a sizeable number of persons due to lung failure— despite RT-PCR and rapid antigen tests showing negative results for the Covid-19 infection— during the surging second wave in Karnataka, has raised concerns among a section of doctors who suspect these cases to linked to new variants of the virus even as scientists reject the theory.

The anecdotal evidence from hospital settings of many patients with RT-PCR negative results showing serious lung damage has also resulted in clinicians calling for greater studies of such cases to understand if the severe lung infections were caused by new mutant variants of the Covid-19 virus – not seen in the first wave in India or the world.

I’m worried, says ER doctor

“I work in the emergency department at the Victoria Hospital. I am worried by some aspects of the infection in the second wave.  At night we get a lot of calls from people saying they do not have RT-PCR reports or they have negative reports and in spite of that they have breathing problems,” said Dr Shiva Kumar, from the emergency unit of the Victoria Hospital.

“If the patients are RT-PCR negative and are still ill then it could be a different strain. I do not have the exact numbers but they are the ones having respiratory problems,’” said the clinician who has seen hundreds of patients through the first and second Covid 19 waves since 2020.

The patients who do not test positive for the Covid-19 virus despite signs of breathing problems are a cause for concern since they may not come on the radar for treatment and would end up in a hospital only after serious lung damage has occurred, he said.

“We feel that when there is a positive report then it could be the old strain and we know how to manage it. It is responding well to our treatment,” Dr Shiva Kumar said.

“I will not say that 50 per cent of cases are like this but it is definitely causing problems. Maybe around three to five per cent of cases we see are in this category. The issue is that we must find out whether this is due to a variant because if it is then later this strain could become dominant and we will be losing more people,” Dr Shiva Kumar said.

“In many cases the viral material may not be in the nasal and throat region and it may be present directly in the lungs. To study this we may need histopathology reports and post mortems. We need studies to find out if the virus is going directly to the lung region, whether it is a post inflammatory reaction or due to immunogenicity,” he said.

On account of the phenomena of Covid-linked lung damage occurring even in those who do not test positive for Covid-19, doctors have now recommended simple pulmonary (lung) function tests like the six-minute walk test, respiratory rate test and a chest x-ray to ascertain the condition of symptomatic patients even if they do not test positive for Covid-19.

‘Follow a syndromic approach’

The incidence of Covid-19 infections, even among those with RT-PCR negative reports, has also prompted health authorities in Karnataka to direct doctors to diagnose for Covid-19 on the basis of a clutch of symptoms – follow a syndromic approach – rather than rely on standard tests for the Covid-19 virus alone.

“During the recent surge an increasing number of false negative reports have been witnessed under both the methods of Covid testing viz RT-PCR and RAT enhancing the necessity of admitting and treating a large number of patients under the syndromic approach,” the Karnataka health department said in an order issued on April 28.

The new kind of cases involve symptoms in the first week and lung inflammation by the second week and lung fibrosis by the third week – where the lungs become like hard rubber,” said Dr Shiva Kumar, the Covid-19 emergency in-charge at the Victoria Hospital.

“I have been seeing Covid cases at close quarters for the last two years and I have practical experience. It is up to ICMR and other bodies to look into what we are finding,” he said.

Corona syndrome

A record number of 1,745 Covid-19 deaths occurred in Bengaluru in April including over 1400 deaths in the last two weeks of the month. In the first wave the highest number of deaths recorded was 971 in September 2020. Nearly 17 percent of the current deaths involve patients less than 45 years of age.

“The reason why we are looking at the disease now as a corona syndrome and studying various symptoms to decide on treatment plans is because many people who are testing negative are also having severe lung infection,” said a senior doctor at the St John’s Medical College and Hospital in Bengaluru.  “Nearly 50 per cent of the cases now are among persons below the age of 50, this is the pattern,” the doctor said.

“We have to think about the disease in a syndromic way because the RT-PCR tests only have a 70 per cent sensitivity. The problem is that many patients delay reporting to hospitals when the RT-PCR test is negative. Our effort is to look at the six minute walk test, oxygen saturation, and chest CT scans to decide on treatment. One of the best tests for Covid-19 is loss of taste,” said Dr C Nagaraja, the director of the Rajiv Gandhi Institute of Chest Diseases.

“We still need scientific evidence to say if the false negative cases of Covid-19 infections involve any of the newer variants of the virus. It is easy for anybody to say on a clinical basis but this has to be established through scientific evidence,” Dr Nagaraja said.

Incidentally, the possible involvement of a Covid-19 variant in lung infections seen in patients who do not test positive during RT-PCR and RAT tests has been flagged by doctors from many places around the country during the second wave including AIIMS, Patna.

‘Negative reports not due to new variants’

Scientists involved in the study of the Covid-19 virus and its variants have however pointed out that RT-PCR negative reports in some serious cases are not due to new Covid-19 variants.

“It is rubbish to say RT-PCR tests are missing variants. All RT-PCR tests used today amplify multiple genes. If a test is based on the spike protein – where most mutations are occurring – then one can say that the test is not working. We are not using spike protein and most of the tests are using other genes in amplification,” Prof V Ravi, a former professor of virology at  NIMHANS, who has been associated with studies of the SARS-COV2 virus.

“The myth has emerged because a lot of people in home isolation have not been monitored this time. People are saying they are fine after four or five days. The worsening condition happens in the second week. CT scan is required in the second week and blood markers are required in the second week. Day five to day 12 are the crucial periods in Covid when people have to be monitored closely at home,” Prof Ravi said.

“In terms of clinical behaviour the virus is the same. We are seeing more severe cases because we are seeing five times the number of cases seen earlier. The severity has nothing to do with mutants. There is absolutely no evidence,” he said.

“The pattern remains the same – 80 to 85 per cent of people have mild or asymptomatic infection, 10 to 15 have moderate infection and five percent have severe infection. It is more in younger people now because they have been moving around and they are a larger proportion in the population. Average age was 50 in the first wave and it is 49 now,” he said.

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