THE Omicron variant has a more than two-fold survival rate on plastic surfaces such as face shields and face masks when compared with other coronavirus (Covid-19) mutants, according to a study.
It lives on plastic surfaces for 193.5 hours – compared with the original Wuhan strain, which survived for 56 hours. The Alpha, Beta, Gamma and Delta variants of the virus lived for 191.3 hours, 156.6 hours, 59.3 hours, and 114.0 hours respectively.
The Japanese study, published yesterday prior to a peer-review, on bioRxiv – a free online lifescience portal run by Cold Spring Harbour Laboratory – also revealed that the variant survived for more than 20 hours on human skin.
A team of researchers from the Kyoto Prefectural University of Medicine concluded that Omicron’s high ‘environmental stability’ helped it replace Delta as the dominant variant and spread more quickly.
According to Bahrain experts, the study reinforces the importance of hand hygiene and disinfection.
American Mission Hospital (AMH) pulmonologist Dr Chellaraja Chellasamy explained fomite-borne transmission of the virus, which is spread through inanimate objects.
“There has been a lot of talk about fomite-borne transmission in Covid, especially in the newer variants like Omicron,” Dr Chellasamy told the GDN.
“Fomites are objects or materials that are likely to transmit infection, such as a face mask or shield, clothes, utensils, and furniture.
“However, the principal mode of transmission for all Covid-19 variants is still exposure to respiratory droplets.”
Meanwhile, Dr Chellasamy reassured that despite studies proving Covid-19 viral particles live on surfaces for as long as nine days, they are not infectious as such.
“According to a recent article in Nature, the risk of infection from touching a contaminated surface is less than five in 10,000, which is lower than estimates for SARS-CoV-2 infection via aerosols and lower than surface-transmission risk for influenza or norovirus, provided the contact is within one to three minutes.
“This is why hand hygiene and disinfectants are still important in preventing the spread of Covid-19,” he added.
For the pathogen to enter the host, fomite exposure generally involves a secondary route, such as oral or direct contact. Fomites include, among other things, contaminated vehicles, shovels, clothing, bowls/buckets, brushes, tack and clippers.
Dr Chellasamy’s colleague and AMH internal medicine specialist Dr Anup Abdulla expressed similar sentiments, emphasising Omicron’s rapid infectious rate and high environmental stability.
“Whereas the earlier Delta variant only lasted about five days on plastic surfaces, Omicron can survive for up to eight days, making it more virulent,” he explained.
“However, 20 seconds of proper hand washing and wearing face masks, along with up-to-date vaccination, will help us prevent the spread.”
The survival times of the Wuhan strain, Alpha, Beta, Gamma, Delta, and Omicron variants on the human skin surface were 8.6 hours, 19.6 hours, 19.1 hours, 11 hours, 16.8 hours, and 21.1 hours, respectively, according to the study.
“The research found that Omicron variant had the highest environmental stability among VOCs (variants of concern), suggesting that this high stability may be one of the factors that allowed it to replace Delta and spread rapidly,” the authors wrote.
Despite being more resistant to ethanol than the original Covid-19 strain, all of the variants were completely inactivated on skin after 15 seconds of exposure to alcohol-based hand sanitisers.
“Therefore,” the researchers concluded, “it is highly recommended that current infection control (hand hygiene) practices use disinfectants... as proposed by the World Health Organisation.”
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