Data on Transfer of Human Coronavirus SARS-CoV-2 from Foods and Packaging Materials to Gloves Indicate That Fomite Transmission Is of Minor Importance

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is mainly transmitted via droplets and aerosols. To evaluate the role of transmission by fomites, SARS-CoV-2-specific data on transfer rates from surfaces to hands and from hands to face are lacking. Here, we generated quantitatively controlled transfer rates for SARSCoV- 2 from food items (lettuce, ham, and vegetarian meat alternative [VMA]) and packaging materials (cardboard and plastic) to gloves using a wet, dry, and frozen viral inoculum and from glove to glove using a wet viral inoculum. For biosafety reasons, the transfer from surfaces to hands and hands to face was simulated by using gloves. The cumulative transfer rate was calculated by using the data from the first transfer experiment, food or packaging material to glove, and combined with the transfer rate obtained from the second transfer experiment from glove to glove. The cumulative transfer rates from lettuce (4.7%) and ham (3.4%) were not significantly different (P . 0.05) but were significantly higher (P , 0.05) than that from VMA ("wet"or "frozen"). The wet cumulative transfer rate from VMA (1.3%) was significantly higher than the cumulative transfer rate from frozen VMA (0.0011%). No transfer from plastic or cardboard was observed with a dry inoculum. The plastic packaging under wet conditions provided the highest cumulative transfer rate (3.0%), while the cumulative transfer from frozen cardboard was very small (0.035%). Overall, the transfer rates determined in this study suggest a minor role of foods or food packaging materials in infection transmission.