Study: Longer surface life for variant

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Russia reported a new daily high of cases on Sunday, breaking its national record for the third day running as the highly contagious Omicron variants spurs surging infections. AFP

The highly contagious Omicron variant can survive up to eight days on plastic and 21 hours on skin – a much longer period of time than other variants of concern like Alpha, Beta, Gamma and Delta, as well as the original strain, according to a study.

The pre-print study, which has not yet been peer-reviewed, analysed the differences in viral environmental stability between the Sars-CoV-2 strain first detected in Wuhan and all variants of concern (VOCs).

The findings showed that on plastic and skin surfaces, the Alpha, Beta, Delta and Omicron variants exhibited more than twofold longer survival times than those of the strain in Wuhan and maintained infectivity for more than 16 hours on the skin surfaces.

Omicron survived 21.1 hours on skin models from cadavers, followed by the original strain (8.6 hours) and the Gamma (11 hours) and Delta (16.8 hours) variants.

The survival of Alpha (19.6 hours) and Beta (19.1 hours) was found to be similar.

“The Omicron variant has the highest environmental stability among the 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.

Further, the team found that Omicron can survive 193.5 hours (about eight days) on a plastic (polystyrene) surface, more than three times that of the original strain (56 hours) and the Gamma variant (59.3 hours), and significantly more than Delta (114 hours) and Beta (156.6 hours). Only the Alpha variant, with 191.3 hours, showed similar resistance.

The researchers said that the high environmental stability of these VOCs could increase the risk of contact transmission and contribute to the spread of VOCs.

The study also showed that although the Alpha, Beta, Delta, and Omicron variants showed a slight increase in ethanol resistance, all VOCs on the skin surface were completely inactivated in 15 seconds of exposure to alcohol-based hand sanitiser.

The researchers highly recommended hand hygiene practices and the use of disinfectants with appropriate alcohol concentrations, as proposed by the World Health Organisation.

This study also acknowledged limitations, such as the relationship between the amount of virus remaining on the surface and the risk of transmission, which is still unclear at this stage.

Therefore, it might be reasonable to interpret the value of survival time in this study as a reference value, the researchers said.

THE STATESMAN (INDIA)/ASIA NEWS NETWORK