Decay pattern of SARS-CoV-2 RNA surface contamination in real residences

Area of Science:

• Environmental Science
• Epidemiology
• Virology

Background:

• Understanding SARS-CoV-2 RNA decay on surfaces is crucial for pandemic preparedness.
• Limited data exists on fomite contamination patterns in residential settings during the COVID-19 pandemic.

Purpose of the Study:

• To investigate the decay patterns of SARS-CoV-2 RNA on surfaces in COVID-19 patient residences.
• To identify factors associated with surface contamination and determine the persistence of SARS-CoV-2 RNA.

Main Methods:

• Collected 2,233 surface samples from 21 object categories in 141 residences during Shanghai's Omicron wave (Spring 2022).
• Analyzed SARS-CoV-2 RNA presence, decay rates, and associations with patient/residence characteristics.
• Applied a first-order decay model to quantify contamination persistence.

Main Results:

• 8.7% of surface samples tested positive for SARS-CoV-2 RNA.
• Basins, water taps, and sewer inlets showed the highest contamination rates (>20%).
• SARS-CoV-2 RNA levels significantly decreased over time, fitting a first-order decay model (0.77±0.07 day⁻¹), indicating a 90% reduction in 3 days.
• Higher contamination in public corridors correlated with increased new COVID-19 cases in the building.

Conclusions:

• Fomite transmission likely played a limited role in COVID-19 spread, considering rapid RNA decay and potential lower viability.
• Surface contamination of SARS-CoV-2 RNA diminishes significantly within three days in residential environments.
• Findings offer insights into transmission dynamics and inform community-based prevention strategies for future infectious disease threats.