A recent study by the School of Public Health, LKS Faculty of Medicine of The University of Hong Kong (HKUMed) found that the Omicron BA.1 SARS-CoV-2 variant is more stable than its ancestral strain on smooth and porous surfaces. It can be recovered from smooth surfaces up to seven days after incubation. The findings are now published in BioRxiv [link to the publication].

The stability of the ancestral strain of SARS-CoV-2 and Omicron BA.1 SARS-CoV-2 variant was examined on five different surfaces, i.e. stainless steel, polypropylene, glass, tissue paper and printing paper. It was found that the Omicron BA.1 SARS-CoV-2 variant could still be recovered from smooth surfaces on day 7 after incubation. By contrast, no infectious ancestral SARS-CoV-2 strain, except in one of the three treated glass samples, was recoverable on day 4 post-incubation. Similarly, the Omicron BA.1 SARS-CoV-2 variant could be recovered on the surface of tissue paper and printing paper after 30 minutes post-incubation, while the ancestral strain would be irrecoverable after 5-15 minutes. 

One of the corresponding authors of the study, Professor Leo Poon Lit-man, Professor and Head of Division of Public Health Laboratory Sciences, School of Public Health, HKUMed, called on members of the public to pay close attention to personal and household hygiene. ‘Washing hands frequently and thoroughly, cleaning surfaces with 1:99 diluted household bleach, especially for families with infected patients, is effective in minimising the chance of being infected by contaminated surfaces,’ said Professor Poon.