Omicron may hang around longer on surfaces than original virus, early findings suggest

In the early days of the COVID-19 pandemic, it felt like the virus was everywhere — and on everything.

Some people washed their mail or wore gloves to the grocery store, while policymakers cordoned off playgrounds and encouraged businesses to scrub every surface.

But as the months passed, scientific consensus began to crystallize, suggesting some of those precautions might be missing the bigger picture of how the SARS-CoV-2 virus transmits.

The main way people get infected, most leading public health officials and scientists now agree, is through exposure to this virus through the air, not through contaminated surfaces known scientifically as "fomites."

Yet Omicron, the highly-contagious variant known for slipping around some of our best defences, might be surviving longer on everyday objects than its early predecessor — raising questions about which basic precautions to prevent surface-based transmission might still be warranted. 

That's a key finding from a new pre-print paper from researchers at the University of Hong Kong's school of public health, which is published online but has not yet been peer-reviewed.

After conducting lab-based research, the team found Omicron "is more stable than the ancestral SARS-CoV-2 on different surfaces."

"Our findings imply that (Omicron) has an increased likelihood to be transmitted by the fomite route," the researchers concluded.

"Hand hygiene and frequent disinfection of common touch surfaces in public areas are highly recommended."

Building off other recent research which showed Omicron's heavily-mutated spike protein is more stable than the ancestral strain, and their own previous findings on SARS-CoV-2's level of infectiousness on various surfaces, the Hong Kong team explored what would happen if droplets containing Omicron — the BA.1 lineage, specifically — were applied to surfaces like stainless steel, paper, and glass.

In each instance, infectious amounts of Omicron were recovered for longer amounts of time than the samples of the original virus.

On several types of paper, infectious amounts of ancestral SARS-CoV-2 were only recoverable for five to 15 minutes — compared to more than 30 minutes for Omicron.

On smooth surfaces, Omicron lasted more than a week, while infectious amounts of the original virus were recovered up to just four days on polypropylene plastic and stainless and up to seven days on glass.

"More evidence is needed to account for the increased transmissibility of (Omicron) observed in various community studies," the researchers wrote.