- Experts already know that Omicron is the most transmissible SARS-CoV-2 variant, but a new study has found that it survives longer than any previous variant on plastic surfaces and skin.
- Scientists do not know whether this persistence leads to more infections.
- According to the new study, Omicron lasts on plastic for nearly 200 hours and on skin for about 21 hours.
The two most recent major variants of the SARS-CoV-2 virus have proven to be more infectious than their predecessors.
Experts increasingly agree that the virus spreads primarily through the air. However, a new study reveals how the evolution of the Omicron SARS-CoV-2 variant may have helped it become dominant.
The Omicron variant survives longer on plastic surfaces and skin than other variants, increasing the likelihood of it spreading through touch.
“Our study showed that on plastic and skin surfaces, Alpha, Beta, Delta, and Omicron variants exhibited more than two-fold longer survival times than those of the Wuhan strain and maintained infectivity for more than 16 [hours] on the skin surfaces,” explain the authors. They continue:
“The high environmental stability of these VOCs [variants of concern] could increase the risk of contact transmission and contribute to the spread of VOCs.”
Prof. Lorna Harries of Exeter University in the United Kingdom, who was not involved in the research, told Medical News Today, “This looks like an interesting study and carefully carried out.”
The study, which has not yet undergone peer review, appears on the preprint bioRxiv server.
According to the study, when on plastic:
- The original version of SARS-CoV-2 survives for 56 hours.
- The Alpha variant survives for 191.3 hours.
- The Beta variant survives for 156.6 hours.
- The Gamma variant survives for 59.3 hours.
- The Delta variant survives for 114 hours.
- The Omicron variant outlasts the other variants, surviving for 193.5 hours.
The researchers also found that the different variants of the virus survive on the skin of cadavers for differing durations:
- The original version of SARS-CoV-2 survives for 8.6 hours.
- The Alpha variant survives for 19.6 hours.
- The Beta variant survives for 19.1 hours.
- The Gamma variant survives for 11 hours.
- The Delta variant survives for 16.8 hours.
- The Omicron variant again outlasts the other variants, surviving for 21.1 hours.
The authors caution that the external environment in which they collected the virus samples may have compromised them. Another possible influence may have been the fluid that the researchers used to prepare the skin samples on which they assessed Omicron’s presence.
In addition, they point out, the reasons for the prolonged Omicron survival time are currently unknown.
Finally, the authors note, “the relationship between the amount of virus remaining on the surface and the risk of transmission is still unclear at this stage.”
For now, they suggest that it is best to consider the survival time for a variant primarily as a reference value until scientists understand more.
The majority of Omicron infections are most likely to occur via airborne particles. Johns Hopkins’ Dr. Amesh Ashok Adalja, who was not involved in the research, told MNT:
“Even if the Omicron and Delta variants have more environmental stability than prior versions of SARS-CoV-2, surface transmission still plays a relatively minor role in the transmission of this virus.”
Dr. Harries agreed, explaining to MNT:
“The major point I would raise here is how common fomite transmission is, with evidence mounting that this is primarily an airborne virus. Nevertheless, any measures to prevent transmission are welcome, and it is reassuring that all variants were inactivated on skin provided people use a hand gel with an appropriate alcohol content.”
The study found that the application of alcohol-based hand sanitizer to the skin for 15 seconds renders all SARS-CoV-2 variants harmless.
“Hand-washing is always a good practice,” said Dr. Adajla.