SARS-CoV-2 was already circulating in Italy, in early December 2019.

Area of Science:

• Virology
• Immunology
• Epidemiology

Background:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the COVID-19 pandemic starting in late 2019.
• The exact timeline of SARS-CoV-2 introduction and spread in Italy remains uncertain.
• Investigating early antibody presence can clarify the virus's initial dissemination.

Purpose of the Study:

• To detect anti-SARS-CoV-2 antibodies in Italian serum samples collected before March 2020.
• To assess the potential for SARS-CoV-2 circulation in Italy prior to the first recognized cases.
• To determine if the virus was present in Italy earlier than its official diagnosis.

Main Methods:

• Retrospective analysis of 234 liver disease patients' and 56 blood donors' serum samples.
• Utilized rapid serologic tests for antibody detection.
• Confirmed positive results with a validated chemiluminescence assay.

Main Results:

• Rapid tests indicated 4.3% IgG and 0.4% IgM positivity in Hep-patients, and 3.6% IgG and 3.6% IgM in blood donors.
• Chemiluminescence assay confirmed IgG positivity in 3 Hep-patients and 1 blood donor, and IgM positivity in 1 Hep-patient.
• No RNAemia was detected, suggesting a negligible risk of transfusion transmission.

Conclusions:

• Findings suggest early circulation of SARS-CoV-2 in Italy, predating documented cases.
• Rapid serologic tests are beneficial but require confirmatory assays to ensure accuracy.
• This study highlights the importance of retrospective serological studies for understanding viral spread.