Has the coronavirus really “weakened” in Italy?

There was a provocative report today that suggested that a fundamental change had occurred in the SARS-COv2 coronavirus in Italy. 

Dr. Alberto Zangrillo

A senior Italian health official suggested in a Reuters article that the coronavirus had become “much less pathogenic (able to cause illness) in people in Italy. “In reality, the virus clinically no longer exists in Italy,” said Dr. Alberto Zangrillo, the head of the San Raffaele Hospital in Milan in the northern region of Lombardy, which has seen the majority of Italy’s coronavirus cases. Dr. Zangrillo also said some experts were “too alarmist” about the prospect of a second wave of infections and politicians needed to take into account the new reality. 

A second doctor from northern Italy told the national ANSA news agency that he was also seeing the coronavirus weaken. “The strength the virus had two months ago is not the same strength it has today,” said Matteo Bassetti, head of the infectious diseases’ clinic at the San Martino hospital in the city of Genoa. The article was picked up by many major news services.

Dr. Mike Ryan, WHO

The WHO was quick to counter these claims in a response to the statement. “We need to be exceptionally careful that we are not creating a sense that all of a sudden the virus has decided to be less pathogenic. That is not the case at all,” said Dr. Mike Ryan, executive director of the WHO’s emergencies program.

It was noteworthy that the Italian physicians provided no actual evidence that the virus had changed or weakened, but based their conclusions on their perceptions that patients who were infected in Italy at this time (as compared to late April and early May) have milder disease and seem to be shedding less virus. This makes it impossible to accept their claim as presently stated. Further studies examining the virus, looking for changes in the genetic code or its ability to infect human cells in culture are needed before considering this statement as fact.

So why might these physicians perceive a change in COVID infections in Italy if the virus has not changed? The most likely reason is that they are looking at a different infected population that displays a different clinical presentation of COVID infection. 

Italy has the third highest death toll in the world from COVID-19, with 33,415 people dying since the outbreak came to prominence in late February. It still has the sixth highest global tally of cases at 233,019, and importantly, the average age of COVID dead in Italy was over 80 years, which reflects the advanced age of the Italian population. 

Italy’s new COVID infections and fatalities have fallen steadily in May, and the country is releasing lockdown restrictions that are as stringent as anywhere on the world. Testing is being carried out in much younger people with minimal symptoms, not just those who are deathly ill, as was the case in late February and early March. These younger people likely shed less virus due to effective immunity, especially compared to the sick, elderly population the doctors were treating in early March

So while the illness in Italy may appear different today versus two months ago, there is no reason to assume it is because the virus has changed and has become less virulent. The population and dynamics of the infection can give that perception. Proof of specific virus changes will be necessary to believe there is a fundamental alteration in the coronavirus.

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

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