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A study conducted by a major hospital in Milan, Italy, has found that the viral load present in people who now test positive for the coronavirus is decreasing, suggesting the infection may be weakening, according to doctors, whose findings have been greeted with skepticism.
Alberto Zangrillo, head of Milan's San Raffaele Hospital, said the coronavirus might be becoming less lethal and that those who have been recently infected have weaker symptoms than two months ago. "The swabs performed over the last 10 days show a viral load in quantitative terms that was absolutely infinitesimal compared to the ones carried out a month or two months ago," Zangrillo, a physician to former Prime Minister Silvio Berlusconi, told Italy's public broadcaster, RAI.
The president of the scientific body advising the government on the pandemic says he is "baffled" by the claim. Italy has the third-highest coronavirus death toll in the world, with 33,475 people dying since the outbreak emerged it February, according to Italy's Civil Protection agency. After a strict national lockdown, which is now being eased, infections and fatalities have fallen steadily.
Italian government officials are urging caution about the claim of the virus turning less lethal, warning it could confuse Italians. "We should instead invite Italians to maintain the maximum caution, maintain physical distancing, avoid large groups, to frequently wash their hands and to wear masks," Sandra Zampa, an undersecretary at the health ministry, said in a statement.
Epidemiologists outside Italy are skeptical.
Oscar MacLean, of the MRC-University of Glasgow Center for Virus Research in Scotland, 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."
COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
MacLean added, "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."
Nonetheless, in the face of a media storm about the findings, doctors and researchers at San Raffaele Hospital are standing firm. Massimo Clementi, director of the Microbiology and Virology Laboratory at the hospital, says an analysis of 200 patients suggests the virus has "enormously weakened."
Skeptics question Zangrillo's motivation. He has clashed with critics for saying the fear of a second wave of coronavirus infections is misplaced, according to Italian newspapers.
"We've got to get back to being a normal country. Someone has to take responsibility for terrorizing the country," he said Sunday. He noted previous epidemics such as MERS and SARS "petered out by themselves." He also said, "We've got to be wary, yes, but not kill ourselves unnecessarily. Our wards are emptying out."
Currently, close to 6,400 people are hospitalized with 435 people in intensive care in Italy. More than 32,250 people are self-isolating at home with symptoms of the virus, according to the Civil Protection agency.
San Raffaele Hospital is also receiving support from some other experts. The head of the infectious diseases clinic at San Martino hospital in the city of Genoa, Matteo Bassetti, told Italy's ANSA news agency he is seeing the same trend. "The strength the virus had two months ago is not the same strength it has today," he said, adding, "It is clear that today the COVID-19 disease is different."
Franco Locatelli, the president of the National Health Council which advises the Italian government, said he could only express "great surprise and absolute bafflement" at the claims.
"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," he told ANSA.
Allan Cheng, an infectious diseases physician at The Alfred hospital in Melbourne, Australia, said, "We haven't noticed any difference in viral loads in people we've tested."
He told Australian media, "We'd be pretty surprised, if that was the case. This is not a virus that mutates all that quickly."
He said the difference in viral loads the Milan hospital is seeing could well be explained by an increase in their testing of people who have not fallen very sick from the coronavirus.