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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Phi 6 recovery from inoculated fingerpads based on elution buffer and methodology

Phi 6 (Φ6) bacteriophage is a proposed surrogate to study pathogenic enveloped viruses including SARS-CoV-2-the causative agent of COVID-19-based on structural similarities, BSL-1 status, and ease of use. To determine the role of virus-contaminated hands in disease transmission, an enhanced understanding of buffer and method performance for Φ6 recovery needs to be determined. Four buffer types and three methodologies were investigated for the recovery of Φ6 from human fingerpads over a 30 min duration. Phosphate buffered saline (PBS), PBS + 0.1 % Tween, 0.1 M glycine + 3% beef extract, and viral transport medium were evaluated as buffers for recovery of Φ6 via a dish, modified glove juice, and vigorous swabbing method. Φ6 concentrations on fingerpads were determined at 0-, 5-, 10-, and 30-min post-inoculation. While there were observed differences in virus recovery across buffer and method types depending on the time point, log PFU recovery based on buffer type or methodology was not significantly different at any time point (P > 0.05). The results presented in this study will allow for future work on Φ6 persistence, transfer between hands and surfaces, and efficacy of hand hygiene methods to be performed using a well-characterized and validated recovery method.