RT Journal Article
SR Electronic
T1 Seroprevalence of anti-SARS-CoV-2 IgG among healthcare workers of a large university hospital in Milan, Lombardy, Italy: a cross-sectional study
JF BMJ Open
JO BMJ Open
FD British Medical Journal Publishing Group
SP e047216
DO 10.1136/bmjopen-2020-047216
VO 11
IS 2
A1 Andrea Lombardi
A1 Davide Mangioni
A1 Dario Consonni
A1 Lisa Cariani
A1 Patrizia Bono
A1 Anna Paola Cantù
A1 Basilio Tiso
A1 Michele Carugno
A1 Antonio Muscatello
A1 Giovanna Lunghi
A1 Angela Cecilia Pesatori
A1 Luciano Riboldi
A1 Ferruccio Ceriotti
A1 Alessandra Bandera
A1 Andrea Gori
YR 2021
UL http://bmjopen.bmj.com/content/11/2/e047216.abstract
AB Objectives 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.Design Cross-sectional study.Setting Monocentric, Italian, third-level university hospital.Participants All the employees of the hospital on a voluntary base, for a total of 4055 participants among 4572 HCWs (88.7%).Primary and secondary outcome measures 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).Results 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<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<0.001). The symptoms most frequently associated with a positive serology were taste and smell alterations (OR 4.62, 95% CI: 2.99 to 7.15) and fever (OR 4.37, 95% CI: 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<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%).Conclusions 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.