SARS-CoV-2 was circulating in Italy before China recognized its existence

The coronavirus disease (COVID-19) pandemic first emerged in Wuhan City, China, in late December 2019. From there, it has spread to 191 countries and territories, infecting over 55.5 million people worldwide.

The emergence of the SARS-CoV-2 virus is thought to be tied to a wet market in Wuhan. But now, new evidence from Italy suggests that the virus may have been lingering around even before December 2019.

The Italian team of scientists found severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in people across several Italian regions as far back as September 2019.

This study, published in the Tumori Journal, sheds light on the possibility that the virus had been spreading in Italy well before the outbreak was officially reported in Wuhan, China.

Study: Unexpected detection of SARS-CoV-2 antibodies in the prepandemic period in Italy. Image Credit: columbo.photog / Shutterstock

Italy's first reported cases

Italy reported its first cases of COVID-19 when two tourists from China tested positive for SARS-CoV-2 in Rome. The first laboratory-confirmed Italian COVID-19 case was detected in Lombardy on February 20, 2020. The male patients had no history of possible contacts with positive cases in Italy or abroad.

Within a few days, more cases were recorded in the area. Soon, the government imposed a lockdown in the country to contain the virus spread.

It is widely believed that the virus had been circulating in Italy since January 2020. However, the rapid spread of the virus, the large number of people requiring hospitalization, and treatment in intensive care units suggest that the virus's arrival in a less symptomatic form could be several months prior.

So far, Italy has over 1.23 million cases and a staggering 46,464 deaths.

Serologic assays

Serologic tests or assays measure the antibody response in a person. Antibodies to COVID-19 are produced over days to weeks after infection.

The presence of antibodies shows that a person has been infected with SARS-CoV-2, irrespective of whether he had severe or mild disease. The test can also detect those who had an asymptomatic infection.

Anti-SARS-CoV-2 antibody response analyses in patients with COVID-19 showed that within 13 days after the onset of symptoms, seroconversion of antiviral immunoglobulin G (IgG) or immunoglobulin M (IgM) was present in almost 100 percent of patients.

The study

To arrive at the study findings, the research team investigated the frequency, timing, and geographic distribution of SARS-CoV-2 exposure in a series of 959 asymptomatic individuals, using SARS-CoV-2 binding and neutralizing antibodies on the plasma samples repository.

These individuals were originally enrolled in a prospective lung cancer screening trial between September 2019 and March 2020 to track the date of onset, frequency, and temporal and geographic variations in lung cancer across the Italian regions.

The study findings

The researchers performed receptor-binding domain (RBD)-specific enzyme-linked immunosorbent assay (ELISA) testing. Of the 959 plasma samples, 111 showed SARS-CoV-2 RBD-specific antibodies (IgM, IgG, or both). Specifically, they detected IgM antibodies in 97 samples and IgG antibodies in 16 samples. All of the patients had no symptoms at the time blood samples were collected.

In the first two months of the study, the researchers revealed that 14.2 percent of the patients in September and 16.3 percent in October exhibited SARS-CoV-2  IgG or IgM antibodies, or both. The team found the first positive case (IgM-positive) on September 3 in the Veneto Region, followed by one case in Emilia Romagna on September 4, Liguria on September 5, and one in Lazio on September 11.

By the end of September, 13 of the 23 positive samples were detected in Lombardy, Italy's hardest-hit region. The team also detected three cases in Veneto, two in Piedmont, and one in Liguria, Emilia Romagna, Campania, Lazio, and Fruili.

Further analysis showed two heights of positivity for anti-SARS-CoV-2 RBD antibodies. The first one began at the end of September, reaching 18 percent in the third week of October. The second one happened in February 2020, with a peak of more than 30 percent of IgM-positive cases in the second week.

"Our results indicate that SARS-CoV-2 circulated in Italy earlier than the first official COVID-19 cases were diagnosed in Lombardy, even long before the first official reports from the Chinese authorities, casting new light on the onset and spread of the COVID-19 pandemic," the researchers conclude.

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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  1. John Farmer John Farmer United States says:

    Was this the original virus?  There has been many reports about how traces of SarsCov2 have been found in frozen sewage samples going back as far as March 2019.  However where are all the deaths?  We have yet to find a sample pre November 2019 that has been fully sequenced.    I suspect that this pre November virus did not have the Polybasic furin Cleavage site in it.  Studies show this is what makes this Coronavirus so deadly and so contagious.  So where did these 12 nuclides come from?   One possibility is that WIV used Gain Of Function techniques to insert them into the virus.   Dr. Shi of The WIV successfully inserted these 12 nuclides into a rat coronavirus back in 2008.

  2. John Farmer John Farmer United States says:

    Why dont you post my comments

  3. Nadine Burnett Nadine Burnett United States says:

    There are pretty serious methodological concerns about the study. In low seroprevalence environments these assay need to be interpreted with caution. Not to mention that their assay mainly detected IgM which is known for having poor reliability and cross-reactivity with other infections, in addition to the issues with RF factor.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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