Frontiers in Medicine (Feb 2021)

Active Surveillance of Asymptomatic, Presymptomatic, and Oligosymptomatic SARS-CoV-2-Infected Individuals in Communities Inhabiting Closed or Semi-closed Institutions

  • Nicolás Ambrosis,
  • Pablo Martin Aispuro,
  • Keila Belhart,
  • Daniela Bottero,
  • Renée Leonor Crisp,
  • María Virginia Dansey,
  • María Virginia Dansey,
  • Magali Gabrielli,
  • Oscar Filevich,
  • Valeria Genoud,
  • Alejandra Giordano,
  • Min Chih Lin,
  • Min Chih Lin,
  • Anibal Lodeiro,
  • Anibal Lodeiro,
  • Felipe Marceca,
  • Felipe Marceca,
  • Nicolás Pregi,
  • Nicolás Pregi,
  • Federico Remes Lenicov,
  • Luciana Rocha-Viegas,
  • Luciana Rocha-Viegas,
  • Erika Rudi,
  • Guillermo Solovey,
  • Guillermo Solovey,
  • Eugenia Zurita,
  • Adali Pecci,
  • Adali Pecci,
  • Roberto Etchenique,
  • Roberto Etchenique,
  • Daniela Hozbor

DOI
https://doi.org/10.3389/fmed.2021.640688
Journal volume & issue
Vol. 8

Abstract

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Background: The high COVID-19 dissemination rate demands active surveillance to identify asymptomatic, presymptomatic, and oligosymptomatic (APO) SARS-CoV-2-infected individuals. This is of special importance in communities inhabiting closed or semi-closed institutions such as residential care homes, prisons, neuropsychiatric hospitals, etc., where risk people are in close contact. Thus, a pooling approach—where samples are mixed and tested as single pools—is an attractive strategy to rapidly detect APO-infected in these epidemiological scenarios.Materials and Methods: This study was done at different pandemic periods between May 28 and August 31 2020 in 153 closed or semi-closed institutions in the Province of Buenos Aires (Argentina). We setup pooling strategy in two stages: first a pool-testing followed by selective individual-testing according to pool results. Samples included in negative pools were presumed as negative, while samples from positive pools were re-tested individually for positives identification.Results: Sensitivity in 5-sample or 10-sample pools was adequate since only 2 Ct values were increased with regard to single tests on average. Concordance between 5-sample or 10-sample pools and individual-testing was 100% in the Ct ≤ 36. We tested 4,936 APO clinical samples in 822 pools, requiring 86–50% fewer tests in low-to-moderate prevalence settings compared to individual testing.Conclusions: By this strategy we detected three COVID-19 outbreaks at early stages in these institutions, helping to their containment and increasing the likelihood of saving lives in such places where risk groups are concentrated.

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