Story at a glance
- The omicron variant of the SARS-CoV-2 coronavirus was responsible for a wave of cases in the U.S. and many countries around the world.
- Although health experts are mainly concerned about transmission through the air, understanding how long the virus can stay intact on surfaces can be helpful.
- Recent studies have found that the omicron variant lasts longer on surfaces and human skin than any previous variant.
Health experts have agreed that the SARS-CoV-2 coronavirus causing COVID-19 is mostly transmitted through the air. However, there were concerns, especially early in the pandemic, about it getting transferred by touching surfaces containing the virus. Researchers have continued to investigate this line of inquiry to get a more complete understanding of how the virus spreads and exists in the environment. In two recent studies, teams of researchers found that the omicron variant lasted longer on surfaces and on human skin compared to other variants.
The studies test omicron and previous variants on surfaces people would find in their daily lives, and one of the studies tests it on human skin samples. Both are available as pre-prints, meaning that they have yet to go through the peer-review process to be published in an academic journal.
In the first study, researchers obtained human skin samples from autopsy specimens for the experiment. They also used plastic as another test surface. Virus survival time was calculated as time when they were no longer able to detect virus in the samples placed on the surfaces. The original SARS-CoV-2 strain found in Wuhan lasted 56 hours on the plastic surface. Later variants alpha, beta, gamma and delta lasted for about 191, 157, 59 and 114 hours, respectively. The omicron variant lasted 193.5 hours.
On human skin, the original coronavirus lasted 8.6 hours. The later variants ranged from 11 to 19.6 hours, and omicron lasted for 21.1 hours on human skin.
In the second study, researchers compared how long original SARS-CoV-2 and the omicron variant survived on smooth versus porous surfaces like stainless steel, polypropylene sheet, glass, facial tissue paper and printing paper. This study did not include other variants like delta in the experiments.
They found that omicron was overall more stable than the original strain on all surfaces. After two days, most of the original strain was gone from the stainless steel, polypropylene sheet and glass. After four days, virus was found only on the glass surface. For the omicron variant, the researchers could recover virus from the surfaces seven days later.
On the porous surfaces, the original coronavirus could not be recovered from facial tissue after 30 minutes. On printing paper, the amount of virus detected after 5 minutes was reduced by 99.68 percent and no virus could be retrieved after 15 minutes. The omicron variant could be detected on facial tissue paper and on printer paper after 30 minutes.
The results from these two studies are in line with previous studies. A paper published in Nature in Jan. 2021 found the coronavirus after 21 days on plastic, 14 days on stainless steel, 7 days on nitrile gloves and 4 days on chemical resistant gloves, although at much lower quantities. More than 95 percent of the virus was gone from the stainless steel surface after 24 hours. It was greatly reduced by the four hour mark on cotton and undetectable after 24 hours.
Although it is inappropriate to directly compare the studies because of differences in how the experiments were set up, the new studies on omicron may shed light on how it compares to past variants of the coronavirus. Because it can stay intact in the soil, on various materials like plastic and steel, it’s important to consider how it factors into risk of infection. A better understanding of the survival of SARS-CoV-2 and any new variants in the environment and on surfaces may help in limiting its spread.
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