According to a study, the highly contagious Omicron variant of Covid-19 can survive up to eight days on plastic and 21 hours on skin – a much longer period of time than other variants of concern such as Alpha, Beta, Gamma, and Delta, as well as the original strain.
The study, which was published as a pre-print and has not yet been peer-reviewed, looked at the differences in viral environmental stability between the SARS-CoV-2 Wuhan strain and all variants of concern (VOCs).
The findings revealed that Alpha, Beta, Delta, and Omicron variants had more than two-fold longer survival times on plastic and skin surfaces than the Wuhan strain and maintained infectivity for more than 16 hours on skin surfaces.
Omicron virus survived 21.1 hours on cadaver skin models, followed by Wuhan virus (8.6 hours), Gamma virus (11 hours), and Delta virus (16.8 hours).
The survival times of Alpha (19.6 hours) and Beta (19.1 hours) were discovered to be comparable.
“The Omicron variant has the highest environmental stability among VOCs,” said researchers from the Kyoto Prefectural University of Medicine in Japan.
“This high stability might also be one of the factors that have allowed the Omicron variant to replace the Delta variant and spread rapidly,” they said.
Furthermore, the team discovered that Omicron can survive on a plastic (polystyrene) surface for 193.5 hours (about 8 days), which is three times longer than the original strain (56 hours) and the Gamma variant (59.3 hours), and significantly longer than Delta (114 hours) and Beta (114 hours) (156.6 hours). Only the Alpha variant, with 191.3 hours of resistance, demonstrated a comparable level of resistance.
According to the researchers, the high environmental stability of these VOCs may increase the risk of contact transmission and contribute to VOC spread.
Although the Alpha, Beta, Delta, and Omicron variants showed a slight increase in ethanol resistance, all VOCs on the skin surface were completely inactivated after 15 seconds of exposure to alcohol-based hand sanitizer.
The researchers strongly advised using hand hygiene practises and disinfectants with appropriate alcohol concentrations, as recommended by the World Health Organization.
This study also acknowledged limitations, such as the fact that the relationship between the amount of virus remaining on the surface and the risk of transmission remains unknown at this time. As a result, the researchers believe it is reasonable to interpret the value of survival time in this study as a reference value.