{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T18:06:22Z","timestamp":1791309982233,"version":"4.3.1"},"reference-count":32,"publisher":"BMJ","issue":"2","license":[{"start":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T00:00:00Z","timestamp":1613952000000},"content-version":"unspecified","delay-in-days":21,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2021,2,4]]},"published-print":{"date-parts":[[2021,2]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To assess the seroprevalence of anti-SARS-CoV-2 IgG among health careworkers (HCWs) in our university hospital and verify the risk of acquiring the infection according to work area.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Cross-sectional study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Monocentric, Italian, third-level university hospital.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>All the employees of the hospital on a voluntary base, for a total of 4055 participants among 4572 HCWs (88.7%).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Primary and secondary outcome measures<\/jats:title>\n                    <jats:p>Number of anti-SARS-CoV-2 positive serology according to working area. Association of anti-SARS-CoV-2 positive serology to selected variables (age, gender, country of origin, body mass index, smoking, symptoms and contact with confirmed cases).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>From 27 April 2020 to 12 June 2020, 4055 HCWs were tested and 309 (7.6%) had a serological positive test. No relevant difference was found between men and women (8.3% vs 7.3%, p=0.3), whereas a higher prevalence was observed among foreign-born workers (27\/186, 14.5%, p&lt;0.001), employees younger than 30 (64\/668, 9.6%, p=0.02) or older than 60 years (38\/383, 9.9%, p=0.02) and among healthcare assistants (40\/320, 12.5%, p=0.06). Working as frontline HCWs was not associated with an increased frequency of positive serology (p=0.42). A positive association was found with presence and number of symptoms (p&lt;0.001). The symptoms most frequently associated with a positive serology were taste and smell alterations (OR 4.62, 95%\u2009CI: 2.99 to 7.15) and fever (OR 4.37, 95%\u2009CI: 3.11 to 6.13). No symptoms were reported in 84\/309 (27.2%) HCWs with positive IgG levels. Declared exposure to a suspected\/confirmed case was more frequently associated (p&lt;0.001) with positive serology when the contact was a family member (19\/94, 20.2%) than a patient or colleague (78\/888, 8.8%).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>SARS-CoV-2 infection occurred undetected in a large fraction of HCWs and it was not associated with working in COVID-19 frontline areas. Beyond the hospital setting, exposure within the community represents an additional source of infection for HCWs.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2020-047216","type":"journal-article","created":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T11:42:37Z","timestamp":1613994157000},"page":"e047216","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":23,"title":["Seroprevalence of anti-SARS-CoV-2 IgG among healthcare workers of a large university hospital in Milan, Lombardy, Italy: a cross-sectional study"],"prefix":"10.1136","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0383-9579","authenticated-orcid":false,"given":"Andrea","family":"Lombardi","sequence":"first","affiliation":[{"name":"Infectious Diseases Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy"},{"name":"Department of Pathophysiology and Transplantation, University of Milan, Milano, 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Paola","family":"Cant\u00f9","sequence":"additional","affiliation":[{"name":"Medical Direction, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Basilio","family":"Tiso","sequence":"additional","affiliation":[{"name":"Medical Direction, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michele","family":"Carugno","sequence":"additional","affiliation":[{"name":"Epidemiology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy"},{"name":"Department of Clinical Sciences and Community Health, University of Milano, Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio","family":"Muscatello","sequence":"additional","affiliation":[{"name":"Infectious Diseases Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, 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