The Norwegian publication writes about the results of studies, thanks to which it was possible to find out how long the particles of the coronavirus remain viable, and therefore dangerous to humans, on different surfaces. The virus lives longest on plastic and stainless steel - up to three days.
A team of scientists sponsored by the US National Institutes of Health has studied how long the virus survives in the air, on stainless steel, plastic and cardboard.
One of the major discoveries is that a viable virus can remain in the air as a cloud of small particles for three hours. For comparison, some influenza viruses remain alive in the air for about an hour, and then only under certain circumstances. This is evidenced by a study from 2018.
Coronavirus lives on cardboard for up to 24 hours. But the longest it survives on plastic and stainless steel - up to three days.
This means that the virus can persist for quite a long time on various things, such as cardboard boxes, taps or countertops, but its concentration decreases over time.
Can infect
“This is very important information to better understand how the virus is transmitted and what measures it makes sense to take,” said Gunnveig Grødeland of the Department of Immunology at the University of Oslo.
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This data also confirms how important it is to wash your hands frequently. It is not known how long the virus lives on the skin of their hands, but most people touch their face dozens of times per hour, according to a 2015 study published in the American Journal of Infection Control.
This means people can get the virus by touching surfaces while they have viable particles on them, explains Gunnweig Grödelann.
"We don't know exactly how much virus is needed to get a person sick, but maybe not that much."
Grödeland said that it only takes three particles of the flu virus for a person to get sick. When sneezing, many millions of virus particles are thrown into the air, but, as already mentioned, it is not yet known how many of them are needed for infection in the case of coronavirus.
Temperature
The authors of the new study placed a realistic number of virus particles on various surfaces in the laboratory, and also sprayed the virus on them in the form of an aerosol.
All checks were carried out at temperatures from 21 to 23 degrees with an air humidity of 40%. This is important because the virus lives for different times at different temperatures.
"It's a good starting point, and if it's warmer, the virus will live a little shorter."
But in the Norwegian winter, when surface temperatures are lower, the virus is likely to live a little longer than scientists have established in their experiments, Grödelann adds.
Almost as expected
The authors of the new study compared the findings with the viability of the SARS virus, which resembles the current coronavirus that is raging in many countries around the world today. It turned out that the survival rates of these two viruses on different surfaces are quite similar.
Although the virus that causes Covid-19 is a new coronavirus that has recently begun to spread, its behavior is not very different from other viruses we are more familiar with.
“The flu virus also stays on surfaces for a couple of days, so it's common for this type of virus,” Grödelann says.
Since the virus behaves as expected, then the measures taken should be sufficient. But if the virus behaved completely differently than scientists thought, we would have every reason for concern.
Grödeland also believes that the urgent measures introduced this week to prevent people from infecting each other arrived just in time. "These measures were taken based on knowledge of previously known similar viruses."
“In recent days, the infection has started to spread uncontrollably, so the timing is right,” says the researcher. She considers the last measures necessary, although she admits that they are quite tough. "They can even be strengthened, but so far everything that the authorities are doing looks very correct."
In an attempt to slow the spread of the infection, all schools and kindergartens were closed in Norway. Many other measures have also been taken.
Lasse Biørnstad
