Detection of IgM, IgG and SARS-CoV-2 RNA among the personnel of the University of Milan, March through May 2020: the UNICORN study. Issue 3 (24th March 2021)

• Record Type: Journal Article
• Authors: Milani, Gregorio Paolo; Rota, Federica; Favero, Chiara; Dioni, Laura; Manenti, Alessandro; Hoxha, Mirjam; Pariani, Elena; Albetti, Benedetta; Pesatori, Angela Cecilia; Montomoli, Emanuele; Bollati, Valentina
• Other Names: author non-byline.; Bandi Claudio author non-byline.; Bellini Tommaso author non-byline.; Bonzini Matteo author non-byline.; Buscaglia Marco author non-byline.; Cantarella Carlo author non-byline.; Cantone Laura author non-byline.; Carugno Michele author non-byline.; Casartelli Sergio author non-byline.; D'Alessandro Sarah author non-byline.; Chiara Francesca De author non-byline.; Delbue Serena author non-byline.; Eberini Ivano author non-byline.; Ferrari Luca author non-byline.; Ferraroni Monica author non-byline.; Galastri Laura author non-byline.; Galli Cristina author non-byline.; Iodice Simona author non-byline.; Vecchia Carlo La author non-byline.; Macchi Chiara author non-byline.; Manini Ilaria author non-byline.; Marchi Serena author non-byline.; Mariani Jacopo author non-byline.; Ruscica Massimiliano author non-byline.; Schioppo Tommaso author non-byline.; Tarantini Letizia author non-byline.; Trombetta Claudia Maria author non-byline.; Vicenzi Marco author non-byline.; Zanchetta Giuliano author non-byline.
• Is Part Of: BMJ open. Volume 11:Issue 3(2021)
• Publication Date: 2021-03-24
• Subjects: public health -- epidemiology -- molecular diagnostics; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2020-046800
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objectives: In Italy, the pandemic of COVID-19 resulted in congestion of hospitals and laboratories and probably determined an underestimation of the number of infected subjects, as the molecular diagnosis of SARS-CoV-2 infection was mainly performed on hospitalised patients. Therefore, limited data are available about the number of asymptomatic/paucisymptomatic subjects in the general population across time. To understand SARS-CoV-2 infection in the general population, we have developed a cross-sectional study (the 'UNIversity against CORoNavirus study') to investigate infection trends in asymptomatic/paucisymptomatic subjects in Milan (Italy), between March and June 2020. Participants: The study population included 2023 subjects asymptomatic at the enrolment. Primary outcome measures: A nasal mid-turbinate swab for the detection of SARS-CoV-2 RNA and blood specimen for testing serum antibodies (immunoglobulin M (IgM) and IgG) were collected. Results: Subjects showing positivity for the SARS-CoV-2 RNA and/or for anti-SARS-CoV-2 Ig is 237 (11.7%). Only 1.2% (n=25) of the total population had a positive nasal swab for SARS-CoV-2 and the large majority (21/25) of them were observed in March. A total of 226 subjects (11%) had IgM (n=19; 0.9%), IgG (n=155; 7.7%) or both (n=52; 2.6%) against SARS-CoV-2. Subjects with a present or past SARS-CoV-2 infection did not differ from other subjects as regards the number of cohabiting family members, travels, fever and upper and lower respiratory infection episodes. Conclusions: Results from the present study support the hypothesis that the actual spread of the virus in Lombardy was underestimated in the official records. However, as it is not known how long Ig persist, numbers should be taken cautiously.