What does it mean for the new coronavirus to survive on the surface for several days?

A major study published last week in The New England Journal of Medicine, published last week, found that the new coronavirus could survive for days on certain surfaces or even for hours in aerosols,media reported. The important study provides valuable insights into the life cycle of the new virus in vitro, but some experts say the study does not mean that the virus can last for several days on the surface or easily spread through the air.

What does it mean for the new coronavirus to survive on the surface for several days?

The new study was conducted by a team from the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), the University of California, Los Angeles (UCLA) and Princeton University. To test the stability of SARS-CoV-2, the researchers used a sprayer to simulate a person’s cough, pushing particles carrying the virus into the air. In addition to testing how long the virus remained stable in the form of aerosols, the researchers also studied the surface stability of the virus on four different media: plastic, stainless steel, copper and cardboard.

The general conclusion of the study is that the virus can survive for several days on different surfaces and for several more hours in the form of aerosols.

“Scientists have found that the virus can be detected in aerosols for up to three hours, copper for four hours, cardboard for 24 hours, and plastic and stainless steel for two to three days,” UCLA said in a press release. “

While the above statement is technically correct, the data do not provide evidence that the virus can continue to spread through the air during that time. The study focused on the rate of decay of viruses under various environmental conditions. This rate, known as half-life, records the time it takes for virus particles to die. Understanding the half-life of the virus is the basis for establishing effective public health measures, especially for hospitals.

In the case of stainless steel, the study points out that the median half-life of SARS-CoV-2 is about 13 hours. However, the virus did not fall below the detection threshold for nearly 3 days, so the final conclusion is that it can still be detected for up to two to three days.

“You can identify a virus on the surface, but that doesn’t mean it’s necessarily contagious,” explained Gregory Poland, a vaccine researcher at the Mayo Clinic, last week. “

As Ross McKinney, chief scientific officer of the American Association of Medical Colleges, said last week — “You have to be exposed to a certain level of virus to get infected.” This means that a sufficient amount of viral particles are required to fall on the surface at first so that the surface remains contagious for a considerable period of time.

All this suggests that the level of “detectable” conclusions mentioned in the new study may be scientifically accurate, but the data are not particularly helpful to a person trying to determine how contagious different surfaces may be in the real world.

While it is certainly possible for people to catch the virus from contaminated mail or boxed packages, the virus is unlikely to survive in large numbers throughout delivery. Infectious disease expert Elizabeth McGraw said in a recent media interview that if the number of viruses transmitted through these surfaces is high, people should have seen the large-scale international spread of the virus months ago.

Air propagation

The aerosol data mentioned in the study is another cause for concern, with some arguing that this means the virus is more likely to spread through the air than previously thought. This impression is partly caused by news releases from the media, “Research suggests that people may be infected with the new coronavirus through the air. “

NiH scientist Neeltje van Doremalen, who was involved in the study, made it clear that their study was not evidence of aerosol transmission. But the published study also notes that the study confirms the possibility of aerosol transmission — “Our results suggest that the spread of aerosols and contaminants in SARS-CoV-2 seems reasonable because the virus can survive in aerosols for hours and is contagious.” “

Otto Yang, an infectious disease specialist at UCLA Medical Center, points out that while some things are scientifically plausible, they are also highly unlikely. In response to many misconceptions about the new study, Yang said the data in the study may be technically correct, but it may also be misleading.

The new study provides valuable scientific insights into the stability of the new coronavirus on different surfaces. However, this study also provides a good illustration of how scientific processes can sometimes seem confusing and confusing. As Yang emphasizes, this is a perfect example of how science can even confuse scientists, and expert debate is crucial to understanding the current vast amount of information on the subject. “This explains why expert analysis and debate are important, and why it is important to find expert consensus rather than to believe in any single source. This explains why news published by the media is always contradictory; they seize them when the theory is published and present them as facts when they have not been confirmed or widely accepted,” says Yang.

The study was published in The New England Journal of Medicine.