SARS-CoV-2 antibody dynamics and transmission from community-wide serological testing in the Italian municipality of Vo'

Nat Commun. 2021 Jul 19;12(1):4383. doi: 10.1038/s41467-021-24622-7.

Abstract

In February and March 2020, two mass swab testing campaigns were conducted in Vo', Italy. In May 2020, we tested 86% of the Vo' population with three immuno-assays detecting antibodies against the spike and nucleocapsid antigens, a neutralisation assay and Polymerase Chain Reaction (PCR). Subjects testing positive to PCR in February/March or a serological assay in May were tested again in November. Here we report on the results of the analysis of the May and November surveys. We estimate a seroprevalence of 3.5% (95% Credible Interval (CrI): 2.8-4.3%) in May. In November, 98.8% (95% Confidence Interval (CI): 93.7-100.0%) of sera which tested positive in May still reacted against at least one antigen; 18.6% (95% CI: 11.0-28.5%) showed an increase of antibody or neutralisation reactivity from May. Analysis of the serostatus of the members of 1,118 households indicates a 26.0% (95% CrI: 17.2-36.9%) Susceptible-Infectious Transmission Probability. Contact tracing had limited impact on epidemic suppression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / immunology*
  • COVID-19 / diagnosis
  • COVID-19 / epidemiology
  • COVID-19 / immunology*
  • COVID-19 / transmission*
  • COVID-19 Nucleic Acid Testing
  • COVID-19 Testing / methods*
  • Contact Tracing
  • Female
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin M / blood
  • Italy / epidemiology
  • Male
  • Nucleocapsid
  • SARS-CoV-2 / immunology*
  • Seroepidemiologic Studies
  • Serologic Tests / methods*
  • Spike Glycoprotein, Coronavirus / immunology

Substances

  • Antibodies, Viral
  • Immunoglobulin G
  • Immunoglobulin M
  • Spike Glycoprotein, Coronavirus