Risk of nosocomial transmission of coronavirus disease 2019: an experience in a general ward setting in Hong Kong

Abstract

Background: Coronavirus disease 2019 (COVID-19) was first reported in Wuhan in December 2019 and has rapidly spread across different cities within and outside China. Hong Kong started to prepare for COVID-19 on 31^st December 2019 and infection control measures in public hospitals were tightened to limit nosocomial transmission within healthcare facilities. However, the recommendations on the transmission-based precautions required for COVID-19 in hospital settings vary from droplet and contact precautions, to contact and airborne precautions with placement of patients in airborne infection isolation rooms.

Aim: To describe an outbreak investigation of a patient with COVID-19 who was nursed in an open cubicle of a general ward before the diagnosis was made.

Method: Contacts were identified and risk categorized as 'close' or 'casual' for decisions on quarantine and/or medical surveillance. Respiratory specimens were collected from contacts who developed fever, and/or respiratory symptoms during the surveillance period and were tested for SARS-CoV-2.

Findings: A total of 71 staff and 49 patients were identified from contact tracing, seven staff and 10 patients fulfilled the criteria of 'close contact'. At the end of 28-day surveillance, 76 tests were performed on 52 contacts and all were negative, including all patient close contacts and six of the seven staff close contacts. The remaining contacts were asymptomatic throughout the surveillance period.

Conclusion: Our findings suggest that SARS-CoV-2 is not spread by an airborne route, and nosocomial transmissions can be prevented through vigilant basic infection control measures, including wearing of surgical masks, hand and environmental hygiene.

Keywords: COVID-19; Contact tracing; Coronavirus disease-2019; Infection control; Outbreak; SARS-CoV-2.

Figure 1

Floor plan of Ward A with index patient staying in bed 2 with 10 other patients.

Figure 2

(a) Chest-X-ray of index patient on admission showing bilateral pulmonary infiltrates. (b) Simple facemask (Hudson mask) used for high-flow oxygen therapy on the index patient during her stay in ward A.