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

• Autores: Ambrosis, Nicolás Martín; Aispuro, Pablo Martín; Belhart, Keila; Bottero, Daniela; Crisp, Renée Leonor; Dansey, María Virginia; Gabrielli, Magalí; Filevich, Oscar; Genoud, Valeria; Giordano, Alejandra; Lin, Min Chih; Lodeiro, Aníbal Roberto; Marceca, Felipe; Pregi, Nicolás; Remes Lenicov, Federico; Rocha Viegas, Luciana; Rudi, Erika; Solovey, Guillermo; Zurita, María Eugenia; Pecci, Adali; Etchenique, Roberto; Hozbor, Daniela Flavia
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Medicina; Ciencias Exactas; SARS-CoV-2; COVID-19; Coronavirus; pooling; RT-qPCR; asymptomatic
• Institución: Universidad Nacional de La Plata

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.
Facultad de Ciencias Exactas
Instituto de Biotecnologia y Biologia Molecular
Facultad de Ciencias Agrarias y Forestales