Editor's note: Scientists worldwide are tracing where the COVID-19 came from to understand more about the new virus. According to a new study published on Tumori Journal, Italian scientists found that COVID-19 may have circulated in Italy back in September 2019, months before the first patient was identified in the country as SARS-CoV-2 RBD-specific antibodies were detected in 111 of 959 (11.6%) individuals, starting from September 2019 (14%). CGTN talked to Gabriella Sozzi, corresponding author of the Tumori Journal paper.

CGTN: Could you tell us more about your study published by Tumori Journal? What are the main findings?

Gabriella Sozzi: In our paper, we analyzed the plasma samples collected by 959 asymptomatic individuals enrolled in a prospective lung cancer screening trial between September 2019 and March 2020.

The preliminary results, obtained using other commercial tests available in our institute on a small number of samples, indicated the presence of high frequencies of positive cases. Given the well-known issues related to the low specificity of these assays, we shared our observations with more expert colleagues of the Universities of Milan and Siena for an independent verification. In particular, the colleagues from Siena used a very specific test, already published and largely validated, that identified 111 positive subjects throughout the considered period. Two main peaks were observed: one in October 2019 and one in February 2020 just before the pandemic was declared. Moreover, to further confirm the specificity of the test, they also used the plasma of positives cases to verify if the antibodies were able to specifically neutralize the SARS-CoV-2 virus. Of note, the negative controls included 5 other "common" coronaviruses circulating in Italy in the recent years. Result: in 6 patients, these antibodies were able to neutralize only SARS-CoV-2 and not the other viruses.

CGTN: Does the result mean that the coronavirus was circulating in Italy in September 2019, months before the country's first patient was identified? 

Sozzi: This is probably the most plausible interpretation of the data and what we suggest in the discussion of the paper. There is also the hypothesis of cross-reactivity, but the assay adopted to look for SARS-CoV-2 RBD-specific antibodies, as well as the assay developed by the University of Siena, are very specific for this virus.

CGTN:  How do you think the new findings will reshape the history of the pandemic?

Sozzi: The information that the virus was already in Italy, and probably in the rest of Europe, months before it became pandemic is certainly relevant. In the first aspect, it would explain some suspicious cases of patients with atypical pneumonia hospitalized in Italian hospitals in those months. Secondly, and perhaps more importantly, understanding how the virus behaves during the seasons could allow us to establish earlier containment policies that may vary over the year depending on the virulence of the infection.

CGTN: What is the current situation in Italy? When do you think the COVID-19 pandemic will end?

Sozzi: In Italy, we are in the midst of the second wave. Unlike the first one, which was more limited to particular regions, this one spread throughout the country. We know that a second general lockdown would be unsustainable and we must rely on the common sense of individuals. Today the end seems still far away and the new vaccines will certainly help.

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