Coronavirus disease 2019 (COVID-19) among healthcare workers: A call for a low-threshold in-hospital screening

To the Editor—A recent large study have shown that only 3% of healthcare workers (HCWs) infected with the novel severe acute respiratory coronavirus virus 2 (SARS-CoV-2) have been exposed to an inpatient with coronavirus disease 2019 (COVID-19) prior to the onset of symptoms, suggesting that most HCWs acquire infection in the community, perhaps due to contact with presymptomatic or asymptomatic carriers, rather than in hospital settings.¹ The high prevalence of infection (11%–20%) among HCWs supports this assertion,^2,3 despite the reportedly low risk of nosocomial infection associated with SARS-CoV-2.^1,4,5

Wee et al⁶ recently reported their experience with syndromic surveillance of HCWs for COVID-19. The surveillance was based on symptoms of acute respiratory illness (ARI) and fever. Pointing to community as well as in-hospital secondary transmission, these researchers detected 14 cases of COVID-19 among HCWs with 4 clusters; most were linked via transmission outside of hospital.⁶ However, although syndromic surveillance, based on fever and ARI symptoms, was shown to be effective during the outbreak of severe acute respiratory syndrome (SARS),⁷ it may not be as effective in containment of COVID-19 infection because of different patterns of clinical presentations. Indeed, in the study by Wee et al,⁶ heat maps did not pick up the cluster with suspected intrahospital spread. Moreover, in a study by Tostmann et al² employing a low-threshold screening for SARS-CoV-2, most HCWs with SARS-CoV-2 infection had mild clinical presentations, frequently not including fever or respiratory symptoms. Using the same clinical data, these researchers developed a model, excluding fever and cough, to predict COVID-19 among HCWs with a fair discriminative ability.²

Early identification and control of COVID-19 among HCWs is of paramount importance particularly in the postoutbreak period to prevent in-hospital secondary transmission to other HCWs and inpatients. The concern of transmitting infection into the healthcare system has been highlighted in a recent study in which HCWs were linked to transmission of COVID-19 into long-term healthcare facilities.⁸ Considering that as many as 50% of all SARS-CoV-2 infections are asymptomatic,⁹ it would seem appropriate, when resources are available, to perform routine SARS-CoV-2 nasopharyngeal screening for all HCWs. The prediction model described by Tostmann et al,² rather than fever and ARI symptoms, can be used to guide a targeted screening strategy in settings with limited availability of testing materials.