Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study

Laboratory of Medical Statistics and Biometry, Giulio A. Maccacaro, Department of Clinical Sciences and Community Health, Campus Cascina Rosa, University of Milan, 20133 Milan, Italy

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UOC Direzione Professioni Sanitarie, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy

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Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Virology Unit, 20122 Milan, Italy

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Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Responsabile Infermieristico area Direzione Medica di Presidio, Coordinamento dipartimenti clinici, Servizio Prevenzione Igiene Ospedaliera, 20122 Milan, Italy

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Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Direzione Medica di Presidio, 20122 Milan, Italy

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Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Romeo ed Enrica Invernizzi Paediatric Research Centre, Department of Biosciences, University of Milan, 20122 Milan, Italy

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Fondazione IRCCS Ca’ Granda Ospedale Maggiore, Clinical Laboratory, 20122 Milan, Italy

Authors to whom correspondence should be addressed.

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Contributed equally as first authors.

Int. J. Environ. Res. Public Health 2020, 17(15), 5313; https://doi.org/10.3390/ijerph17155313

Received: 17 June 2020 / Revised: 17 July 2020 / Accepted: 20 July 2020 / Published: 23 July 2020

(This article belongs to the Special Issue Coronavirus and Influenza Epidemiology. Coronavirus Vaccine Studies and Influenza Vaccine Effectiveness. New Challenges in Analysis and Reporting)

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Abstract

Background: Coronavirus Disease 2019 (COVID-19) has rapidly spread worldwide, becoming an unprecedented public health emergency. Rapid detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) suspected cases is crucial to control the spread of infection. We aimed to evaluate the time length of negativization from the onset of symptoms in healthcare workers (HCWs) with COVID-19, and to evaluate significant variations in cycle threshold (CT) values and gene positivity (E, RdRP, and N genes) among positive individuals who returned to work. Methods: We retrospectively analyzed a consecutive cohort of 182 SARS-CoV-2-positive HCWs in Milan, from 16 March to 30 April 2020. Nasopharyngeal swabs were tested by RT-PCR. Results: Asymptomatic HCWs were 17.6% (32/182), and 58 healed at 30 April 2020. The median time length of negativization was 4 weeks (35% of symptomatic versus 40% of asymptomatic HCWs). Four HCWs, healed at 30 April, turned positive within three weeks during controls set up in the work unit. Three-gene positivity had the greatest variability, and increasing CT values from single- to three-gene positivity among all age groups were observed. Conclusions: Self-isolation longer than two weeks and prolonged follow-up periods for the staff returning to work after COVID-19 could be the most suitable choices to counter the SARS-CoV-2 spread. Further studies are needed to investigate infectiousness profiles among positive individuals. View Full-Text

Keywords: SARS-CoV-2; Coronavirus Disease 2019; Reverse Transcription PCR; Cycle Threshold values; health care workers

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MDPI and ACS Style

Cariani, L.; Orena, B.S.; Ambrogi, F.; Gambazza, S.; Maraschini, A.; Dodaro, A.; Oggioni, M.; Orlandi, A.; Pirrone, A.; Uceda Renteria, S.; Bernazzani, M.; Cantù, A.P.; Ceriotti, F.; Lunghi, G. Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study. Int. J. Environ. Res. Public Health 2020, 17, 5313. https://doi.org/10.3390/ijerph17155313

AMA Style

Cariani L, Orena BS, Ambrogi F, Gambazza S, Maraschini A, Dodaro A, Oggioni M, Orlandi A, Pirrone A, Uceda Renteria S, Bernazzani M, Cantù AP, Ceriotti F, Lunghi G. Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study. International Journal of Environmental Research and Public Health. 2020; 17(15):5313. https://doi.org/10.3390/ijerph17155313

Chicago/Turabian Style

Cariani, Lisa, Beatrice S. Orena, Federico Ambrogi, Simone Gambazza, Anna Maraschini, Antonella Dodaro, Massimo Oggioni, Annarosa Orlandi, Alessia Pirrone, Sara Uceda Renteria, Mara Bernazzani, Anna P. Cantù, Ferruccio Ceriotti, and Giovanna Lunghi. 2020. "Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study" International Journal of Environmental Research and Public Health 17, no. 15: 5313. https://doi.org/10.3390/ijerph17155313

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Time Length of Negativization and Cycle Threshold Values in 182 Healthcare Workers with Covid-19 in Milan, Italy: An Observational Cohort Study

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