By Emilio Parodi
MILAN (Reuters) – A small study conducted by researchers in Italy found that COVID-19 patients who had been tested for the new coronavirus in a hospital there in May had fewer virus particles than those who had been tested a month earlier. .
The researchers offered some theories for lower “viral load”, including that blocking measures may have reduced patients’ exposure to the virus, but their study did not provide evidence to explain their discovery.
Another Italian doctor said last month that “the virus 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 San Raffaele Hospital in Milan, said at the time that his comments would be strengthened by published research conducted shortly by fellow scientist Massimo Clementi.
Instead, he looked for links between the severity of the disease and the amount of virus – the viral load – in patients.
The researchers analyzed 200 nasopharyngeal swabs taken from the San Raffaele hospital. Half came from patients treated in April – at the height of the pandemic – and half came from patients treated in May.
Based on the results, the researchers calculated that the viral loads of the patients were higher in April. They also found that patients who underwent tamponades in April had more severe symptoms and were more likely to need hospitalization and intensive care.
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 although 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 than in April, warmer temperatures, greater use of face and handwash masks and less pollution, they said.
(Reporting by Emilio Parodi; Editing by Kate Kelland and Alison Williams)