Characteristics of 1,573 Healthcare Workers Who Underwent Nasopharyngeal Swab for SARS-CoV-2 in Milano, Lombardy, Italy

Abstract

Background: The management of healthcare workers (HCWs) exposed to confirmed cases of COVID-19 is still a matter of debate. It is unclear whether these subjects should be tested in the absence of symptoms and if those can guide diagnosis. Methods: Demographic, epidemiologic and clinical characteristics of all the consecutive HCWs which performed a nasopharyngeal swab for the detection of SARS-CoV-2 in University Hospital from February 24, 2020, to March 31, 2020, were collected. Frequencies of positive tests were compared according to selected variables. Multivariable logistic regression analyses were then applied. Findings: Positive tests were 138 among 1,573 HCWs (8·8%, 95% confidence interval [CI]: 7.4-10.3), with a marked difference between symptomatic (20·2%, 95% CI: 16·7-24·1) and asymptomatic (3·7%, 95% CI: 2·7-5·1) subjects (p<0·0001). Physicians were the group with the highest frequency of positive tests (10·6%, 95% CI: 8·3-13·4) whereas clerical workers and technicians displayed the lowest frequency (2·9%, 95% CI: 0·8-7·3). The likelihood of being positive increased with the number of reported symptoms and the strongest predictors of a positive test were taste and smell alterations (odds ratio [OR]= 29·7) and fever (OR = 7·21). The median time from first positive test to a negative test was 23 days (95% CI: 19-24). Interpretation: In this Italian group of HCWs exposed to confirmed cases of COVID-19 the presence of symptoms, especially taste and smell alterations and fever, was associated with SARS-CoV-2 infection. The median time to clear the virus from nasopharynx was 23 days. Funding Statement: The authors stated that there was none related to the content of this manuscript. Declaration of Interests: The authors reported that there was none related to the content of this manuscript. Ethics Approval Statement: The study was approved by the Ethical Committee of our institution and was conducted in accordance with the Helsinki Declaration.