Environment contamination and intra-hospital spread of COVID-19 in a tertiary care Hospital in Taiwan

The role of environmental contamination in COVID-19 transmission within hospitals is still of interest due to the significant impact of outbreaks globally. However, there is a scarcity of data regarding the utilization of environmental sampling for informing infection control measures during SARS-CoV-2 outbreaks.

This retrospective study analyzed incident event investigations conducted at a single center from May 1, 2021, to August 31, 2021. Investigations were initiated following the identification of a COVID-19 confirmed case (referred to as the index case) who had stayed in a hospital area outside the dedicated COVID-19 ward/bed and without specific COVID-19 precautions. Measures to prevent intra-hospital spread included contact tracing, adjusted testing policies, isolation of confirmed cases, quarantine of close contacts, environmental disinfection, and PCR testing of environmental samples.

Among the 18 incident events investigated, the index case was a healthcare personnel in 8 events, a patient in 8 events, and a caregiver in 2 events. The median number of confirmed COVID-19 cases within 14 days was 13 (IQR, 7-31) for events with SARS-CoV-2 RNA detected on environmental surfaces, compared to only one (IQR, 1-1.5) for events without surface contamination (P = 0.04). Environmental contamination was independently associated with a higher number of COVID-19 cases (P < 0.001).

This study highlights environmental contamination as an indicator of the severity of incident events and provides a framework for incident event management, including a protocol for environmental sampling. Implementing these measures can help prevent the spread of COVID-19 within healthcare facilities.