Is coronavirus becoming less potent? Doctors believe it is weakening

Italian doctors claim coronavirus has ‘enormously weakened’ compared to when it ripped across the globe earlier this year.

Head of Milan’s San Raffaele Hospital Dr Alberto Zangrillo says the disease is now much less lethal and ‘no longer clinically exists’ in Italy. The physician of former Prime Minister Silvio Berlusconi said newly infected patients are showing milder symptoms and that the number of viruses in their system decreased significantly between March and May.

Scientific theory suggests viruses may become weaker in order to survive, as killing or incapacitating too many human hosts will limit their capacity to spread. But not everyone in the scientific community is buying these latest claims.

The president of the government’s scientific advisory body said he was ‘baffled’ by Dr Zangrillo’s remarks, while an epidemiologist at Stanford University called the report ‘bulls**t’.

Viruses like HIV and the common cold have mutated in the same way the research claims. But critics point out these diseases have done so over the course of many years, but coronavirus has only been recorded in humans since December last year.

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Other scientists have said there is not enough evidence to conclude Covid-19 has adapted in this way. The San Raffaele study was based on the swab samples of 200 patients taken over the past 10 days, compared to ones carried out a month ago.

Director of San Raffaele’s Microbiology and Virology Laboratory Massimo Clementi said the viral loads present in these samples showed the virus had ‘enormously weakened’.

Head of the infectious diseases clinic at Genoa’s San Martino hospital Matteo Bassetti backed these claims. He said: ‘The strength the virus had two months ago is not the same strength it has today’.

Dr Zangrillo made his controversial claims on the RAI TV channel. Urging politicians to lift emergency measures faster, he said: ‘In reality, the virus clinically no longer exists in Italy. We’ve got to get back to being a normal country. Someone has to take responsibility for terrorising the country.’

‘I say this well aware of the tragedy for those patients who didn’t make it, but we cannot continue to give all the attention to self-proclaimed professors rather than actual virologists and hospital workers.

‘In a clinical sense, the virus no longer exists. I am prepared to put my name to that statement. We’ve got to get back to being a normal country because the statistics show we have every capability of doing that.’

Italy has suffered the third highest official death toll in the world, with 33,475 lives lost. There have been 233,197 confirmed cases and there are 6,387 patients in hospital, 435 in intensive care and 32,253 self-isolating at home with symptoms.

Dr Zangrillo said previous epidemics including SARS and MERS ‘petered out by themselves’. He added: ‘We’ve got to be wary, yes, but not kill ourselves unnecessarily. Our wards are emptying out,’

President of the National Health Council which advises the government Franco Locatelli said he could only express his ‘great surprise and bafflement’ at the remarks.

He added: ‘You just need to look at the number of new positive cases confirmed every day to see the persistent circulation of the virus in Italy.’

Columbia University’s Dr Angela Rasmussen said there is ‘no evidence that the virus is losing potency anywhere’. She said fewer cases, hospitalisations and deaths doesn’t mean the virus itself is any weaker then before.

Stanford University based epidemiologist Dr Seema Yasmin called for the report to be deleted, branding it ‘bulls**t’.

Professor Francois Balloux from University College London said: ‘There is no evidence for the SARS-CoV-2 (Covid-19) having become more or less virulent/transmissible.

‘The outbreak in Italy has been waning over recent weeks despite relaxation of the social distancing measures previously in place. This is line with what has been observed in most European countries.

‘The extent to which this is only due to residual social distancing measures in place, or whether seasonality or some other factors are playing a role remains debated. That said, we should definitely not rule out a second epidemic wave later this year.

‘The lockdowns were necessary to avoid hospital being overrun. Social distancing measures are being progressively relaxed in countries where the outbreak is under control. I do not believe these comments are helpful or reflect the current scientific evidence.

‘Viral load of swab tests will vary over the course of an infection. When compared on the same day post-infection, viral load can correlate with symptom severity.

‘Transmission outdoors is likely to be characterised by lower infectious dose and less severe symptoms, than transmission indoors.

‘There is no evidence the virus has lost ‘strength’ at this stage. We cannot rule out that some lineages will eventually evolve towards to lower symptom severity but this cannot be taken for granted.’

MRC-University of Glasgow Centre for Virus Research’s Dr Oscar MacLean said: ‘These claims are not supported by anything in the scientific literature, and also seem fairly implausible on genetic grounds.

‘The vast majority of SARS-CoV-2 mutations are extremely rare, and so whilst some infections may be attenuated by certain mutations, they are highly unlikely to be common enough to alter the nature of the virus at a national or global level.

‘We know that susceptibility to the virus significantly differs across age and risk groups, and so infection outcomes will also drastically differ across individuals.

‘As testing efforts are scaled up across the globe, asymptomatic and mild infections which previously would not have been detected, are now much more likely to be identified. It’s important not to confuse this with any weakening on the virus’s part.

‘Making these claims on the basis of anecdotal observations from swab tests is dangerous. Whilst weakening of the virus through mutations is theoretically possible, it is not something we should expect, and any claims of this nature would need to be verified in a more systematic way.

‘Without significantly stronger evidence, no one should unnecessarily downplay the danger this highly virulent virus poses, and risk the ongoing society-wide response.’

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