By Emilio Parodi
MILAN (Reuters) – A small study by researchers in Italy found that COVID-19 patients who underwent testing for the new coronavirus at a hospital there in May had fewer virus particles than those who tested for one month. before.
The researchers offered some theories for the lower “viral load”, including that blocking measures may have reduced patients’ exposure to the virus, but their study provided no evidence to explain their finding.
Another Italian doctor said last month that “the virus clinically no longer exists in Italy,” suggesting that the interaction between the virus and its human host had changed.
Alberto Zangrillo, head of intensive care at the Italian San Raffaele Hospital in Milan, said at the time that his comments would be reinforced by research that will soon be published and co-directed by scientist Massimo Clementi.
But Clementi’s study, published Monday in the journal Clinical Chemistry and Laboratory Medicine, did not look for mutations in the virus or changes in patients that could explain why the disease seemed less severe overall in May patients.
Instead, he looked for links between the severity of the disease and the amount of virus, the viral load, in the patients.
The researchers analyzed 200 nasopharyngeal swabs taken at the San Raffaele hospital. Half were from patients treated in April, at the peak of the pandemic, and the other half were from patients treated in May.
Based on the results, the researchers calculated that the viral loads of the patients were higher in April. Patients who took a swab in April also had more severe symptoms and were more likely to need hospitalization and intensive care, they found.
Viral loads were similar in men and women, but were higher in patients 60 years of age and older, and in those with severe COVID-19.
Clementi’s team said that while it was theoretically possible that the new coronavirus had mutated, they had no molecular data to prove it.
Other possible explanations include a wider use of social distancing in May versus April, warmer temperatures, increased use of face masks and handwashing, and less pollution, they said.
(Report by Emilio Parodi; Edition of Kate Kelland and Alison Williams)
