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Re-testing of blood samples suggests that COVID-19 may — the keyword being "may" — have been in Italy by October 2019, months before the viral disease was flagged up in China, according to a new preprint paper.
Bear in mind, however, this is far from conclusive. The paper is yet to be peer-reviewed and some experts have expressed doubts over its findings.
Back in November 2020, scientists from Italy's National Cancer Institute in Milan tested blood samples from 959 people who had been screened for lung cancer and found that 111 individuals (just over 11 percent of the sample) tested positive for antibodies against SARS-CoV-2, the coronavirus that causes COVID-19. The research sparked lively debate around the timeline of COVID-19, but questions remained over the study's validity.
To affirm the results, researchers have since had 29 samples retested at the VisMederi laboratory in the Italian city of Siena and at the Erasmus Medical Center, an external lab in the Netherlands affiliated with the World Health Organizations (WHO).
The findings, recently posted on the preprint server medRxiv, suggest that almost all of these samples were negative, but three of the samples were found to test positive for some SARS-CoV-2 antibodies by both VisMederi and Erasmus Medical Center. These three samples were collected on October 10, 2019, and November 11 from Lombardy — the first hotspot for COVID-19 in Europe — and February 5, 2020, from Lazio. By the standards of the Erasmus Medical Center, however, the samples did not contain enough evidence of SARS-CoV-2 antibodies to provide conclusive proof of prior COVID-19 infection.
As you may have gathered, this isn't exactly bulletproof evidence that COVID-19 was circulating in Italy as early as October 2019, although it certainly adds to the debate.
Tweeting about the study, Professor Tom Ellis, from the Synthetic Genomics and Synthetic Biology Research Group at Imperial College London, commented: “3 remain as 'possibles' if you look at the results table, and one of these is from Feb 2020 so probably a legit infection. The 11th November case looks interesting. Not so confident about the earlier 10th Oct case. Could it be contamination at a later date?”
“I'm sure this will be of some interest to the origins of covid crowd, but what I find more interesting is the level of disagreement between the testing centers,” he added. “Reproducibility crisis!”
The early timeline of COVID-19 still remains very hazy. The earliest reported case of COVID-19 was a man from Wuhan in the Chinese province of Hubei on December 1, 2019, according to a study published in The Lancet medical journal. However, many pieces of research have suggested that the virus likely emerged sometime before this. One study, for instance, looked at the genetic diversity and mutations found within SARS-CoV-2 during the initial stages of the known outbreak and found the virus was likely circulating in China as early as October 2019.
Beyond China, things aren't much clearer. Europe's first confirmed COVID-19 infection was officially identified in France on January 24, 2020, but researchers have since found evidence of older cases. A hospital in Paris retested a sample taken from a man with a flu-like illness just after Christmas and discovered he was potentially infected with COVID-19 as early as December 27, 2019.
This latest report from Italy is unlikely to settle the debate, but it's not the first bit of research to suggest that COVID-19 was silently lurking across the world weeks and months before it was formally recognized.
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