The Federal Institute for Risk Assessment (BfR) explains that there is currently no reliable evidence of transmission of the novel coronavirus SARS-CoV-2 through contact with contaminated objects or via contaminated surfaces, which would have led to subsequent human infections. However, according to the experts, smear infections via surfaces that were previously contaminated with viruses cannot be ruled out.
It is known that transmission or infection with the coronavirus SARS-CoV-2 occurs via the air (aerosols) and especially via droplets. However, a further spread of the pathogen via surfaces cannot be excluded. On some surfaces the virus can be detected for up to almost a month.
As the BfR explains, the stability of coronaviruses in the environment depends on many factors such as temperature, humidity and the condition of the surface as well as on the specific virus strain and the amount of virus. Human corona viruses are generally not particularly stable on dry surfaces. Inactivation in the dried state usually takes place within hours to several days.
Not very stable on dry surfaces
For the novel coronavirus SARS-CoV-2, laboratory studies by a U.S. research group show that after heavy contamination it can remain infectious for up to three hours as an aerosol, up to four hours on copper surfaces, up to 24 hours on cardboard and up to two to three days on stainless steel and plastic. The results of the researchers were published in “The New England Journal of Medicine”.
And data from another study published in the “Journal of Infection” indicate that SARS-CoV-2 can remain infectious on a metal surface for several days even at elevated temperatures (30 degrees Celsius). However, according to the BfR, drying of the surface within one hour led to a significant reduction in infectivity (100-fold reduction).
Another study by Australian scientists concluded under different laboratory conditions that SARS-CoV-2 could be detected for up to 28 days on various surfaces such as glass, stainless steel and paper at 20 degrees Celsius. The results of this study were published in the Virology Journal.
As known from other viruses, the coronavirus SARS-CoV-2 can remain infectious at low temperatures on moist surfaces for much longer. In a preprint article (a publication that has not yet been reviewed by a peer review process common in science), a research team describes that in laboratory tests SARS-CoV-2 was still infectious on fish, chicken and pork after three weeks of storage at 4°C, -20°C and -80°C, with only a slight reduction in the amount of virus. However, very high virus concentrations were used for the study.
Thus, the stability of the coronavirus SARS-CoV-2 determined in the laboratory is in most cases lower than that of many other pathogens, such as various non-enveloped viruses or bacterial spores. According to the information provided, the stability of these viruses mentioned in the studies was determined in the laboratory under optimal conditions and with high virus concentrations. In practice, however, the stability of the coronavirus SARS-CoV-2 is expected to be lower than determined in the laboratory studies due to additional factors such as daylight, fluctuating temperature and humidity, and lower levels of contamination.
The BfR points out that consumers can protect themselves from virus transmission via surfaces and food by observing general hygiene rules. These include regular hand washing and keeping hands away from the face, thorough washing of hands after contact with food and its packaging, and sufficient washing and heating of food. (ad)
Coronavirus long detectable on surfaces
WashingtonNewsday Health and Wellness.