Low Risk of HCW to Patient Transmission of SARS-CoV-2 in a Tertiary Care Cancer Center June 1, 2020-November 20, 2021

BACKGROUND: Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, several outbreaks have been reported among patients or staff in acute care settings. The highly contagious B.1.617.2 (Delta) variant became the dominant strain in the United States around July 2021, heightening concern for transmission within healthcare facilities. This report outlines the risk of secondary transmission of SARS-CoV-2 from an infected healthcare worker (HCW) to patient, stratified by profession and care setting. METHODS: This study was conducted at a tertiary care cancer center in New York City from June 1, 2020, until December 4, 2021. On March 17, 2020, the study institution offered testing for all staff. Contact tracing was done for patients exposed to a confirmed HCW case of SARS-CoV-2. The exposure period was defined as two days before symptom onset or two days before positive polymerase chain reaction specimen from asymptomatic HCW. RESULTS: From June 1, 2020, to November 20, 2021, 434 HCWs with direct patient contact tested positive for COVID-19. 57% were registered nurses (RN), 11% patient care technicians (PCT), 8% advanced practice providers, 9% physicians, 11% therapists, and 4% in other fields. Most exposures occurred in outpatient clinics (58%). A total of 3,634 patients were contact traced. Among these, 16 (0.44%) tested positive for COVID-19 within two weeks, 7 (0.66%) occurring in patients exposed during admission. 144 (33%) index cases occurred after July 1, 2021, when Delta became the dominant variant, resulting 1,313 patient exposures. 4 transmission events occurred (0.30%) from 4 separate HCWs, 3 of whom were fully vaccinated. CONCLUSIONS: The overall risk of COVID-19 transmission from HCW to patient is low, though increased among RNs and PCTs providing bedside care. Vaccination and implementation of control measures, such as symptom screening and universal masking, mitigates the risk of COVID-19 infection even among immunocompromised patients.