characteristics of 1573 healthcare workers who underwent nasopharyngeal swab testing for sarscov2 in milan lombardy italy objectives the management of healthcare workers hcws exposed to confirmed cases of coronavirus disease 2019 covid19 is still a matter of debate we aimed to assess in this group the attack rate of asymptomatic carriers and the symptoms most frequently associated with infectionmethods occupational and clinical characteristics of hcws who underwent nasopharyngeal swab testing for the detection of severe acute respiratory syndrome coronavirus 2 sarscov2 in a university hospital from 24 february 2020 to 31 march 2020 were collected for those who tested positive and for those who tested positive but who were asymptomatic we checked the laboratory and clinical data as of 22 may to calculate the time necessary for hcws to then test negative and to verify whether symptoms developed thereafter frequencies of positive tests were compared according to selected variables using multivariable logistic regression modelsresults there were 139 positive tests 88 among 1573 hcws 95 confidence interval 75103 with a marked difference between symptomatic 122503 242 and asymptomatic 171070 16 workers p 0001 physicians were the group with the highest frequency of positive tests 61582 105 whereas clerical workers and technicians had the lowest frequency 5137 36 the likelihood of testing positive for covid19 increased with the number of reported symptoms the strongest predictors of test positivity were taste and smell alterations odds ratio 769 and fever odds ratio 912 the median time from first positive test to a negative test was 27 days 95 confidence interval 2430conclusions hcws can be infected with sarscov2 without displaying any symptoms among symptomatic hcws the key symptoms to guide diagnosis are taste and smell alterations and fever a median of almost 4 weeks is necessary before nasopharyngeal swab test results are negative