Unexpected detection of SARS-CoV-2 antibodies in the prepandemic period in Italy

Tumori. 2021 Oct;107(5):446-451. doi: 10.1177/0300891620974755. Epub 2020 Nov 11.

Abstract

There are no robust data on the real onset of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and spread in the prepandemic period worldwide. We investigated the presence of SARS-CoV-2 receptor-binding domain (RBD)-specific antibodies in blood samples of 959 asymptomatic individuals 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 across the Italian regions. SARS-CoV-2 RBD-specific antibodies were detected in 111 of 959 (11.6%) individuals, starting from September 2019 (14%), with a cluster of positive cases (>30%) in the second week of February 2020 and the highest number (53.2%) in Lombardy. This study shows an unexpected very early circulation of SARS-CoV-2 among asymptomatic individuals in Italy several months before the first patient was identified, and clarifies the onset and spread of the coronavirus disease 2019 (COVID-19) pandemic. Finding SARS-CoV-2 antibodies in asymptomatic people before the COVID-19 outbreak in Italy may reshape the history of pandemic.

Keywords: COVID-19; SARS-CoV-2 antibodies; Screening.

MeSH terms

  • Aged
  • Antibodies, Viral / blood*
  • Asymptomatic Infections
  • COVID-19 / epidemiology*
  • Female
  • Humans
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Prospective Studies
  • SARS-CoV-2 / immunology*

Substances

  • Antibodies, Viral