About Coronaviruses, Surfaces and PREVOSAN
How long can SARS-CoV-2 viruses survive on surfaces?
Bacteria and viruses can survive on metal, glass or plastic surfaces for a very long time. In the case of the SARS-CoV-2 virus, the viruses can survive several days on such surfaces [G. Kampf et al. / Journal of Hospital Infection 104 (2020) 246-251].
How does PREVOSAN work?
PREVOSAN works in two ways:
PREVOSAN contains silver chloride. This releases very small amounts of silver ions on moist surfaces, which attack and destroy the germs’ membranes. This antibiotic effect has long been known in the case of silver cutlery.
PREVOSAN is also photo-oxidative. Daylight or artificial daylight from fluorescent tubes or LED spotlights trigger charge shifts and photocatalytic processes. Viruses or bacteria that are on PREVOSAN surfaces are physically destroyed. Such effects are used, for example, with self-cleaning wall paints.
How has the effectiveness of PREVOSAN been proven?
The renowned English testing institute IMSL (Industrial Microbiological Service Limited) has tested PREVOSAN in a practical droplet test. Phi6 bacteriopharges, which are very similar to coronaviruses, were dissolved in liquid and applied to PREVOSAN in tiny droplets. At room temperature, 50% humidity and artificial daylight, these dry up quickly. After 1 hour and after 2 hours, the effectiveness of the dried virus substance was determined by means of bacteria that serve as host.
After 1 hour, 95% of the viruses are deactivated.
After 2 hours, 99.9% of the viruses are deactivated.
How is the validity of the droplet test?
The usual test method for virucidal surfaces is specified in the ISO 21702 standard. Here the test is carried out in a permanently moist environment. Water-soluble substances such as silver or copper ions are very mobile under such conditions and have a very good effect on the pathogens. This often makes them seem much more effective than they really are.
The droplet test simulates the practical conditions in which the surfaces dry quickly and only a minimal film of moisture remains, much better. Because of this, we only rely on this test.
The testing institute IMSL is leading the development of improved test methods for this area.
Does PREVOSAN also affect bacteria?
The effect of PREVOSAN on the intestinal bacterium E. Coli, which can cause various diseases and multiplies well on many surfaces, was examined by the Federal Institute for Materials Research and Development (BAM) in accordance with ISO 22196:
After one hour, the bacteria count has decreased by 99.999%.
How does the smear infection work in the case of Covid-19?
Covid 19 is transmitted via the so-called droplet infection: infected people excrete the viruses via droplets of saliva with the air they breathe.
These can get to surfaces and from there are transferred via the hands to the mucous membranes (nose, mouth, eyes) of healthy people. There are cells that can be attacked by the virus, causing Covid 19 to be triggered.
Therefore, the recommendation is to wash your hands very often and not to touch your face.
Is PREVOSAN a biocidal product?
According to the biocidal product regulation EU 528/2012, PREVOSAN is a treated product. Due to its primary biocidal use, has to be registered as a biocidal product. It is registered in Germany under BAuA No.-96251. The active ingredient is silver chloride. The silver chloride content is 22 mg / m². Silver chloride is also approved for direct food contact.
How relevant is the smear infection for the transmission of Covid-19?
Infectious droplets can infect healthy people in a number of ways.
The droplets can be absorbed directly with the air you breathe. This is where distance and wearing masks help.
Very small droplets of so-called aerosols (diameter <5 µm) can remain in the air for a long time. However, the volume of the aerosols and thus the number of viruses contained is very small compared to the total volume of the excreted liquid. Around 99% of the infectious material has a diameter> 100 µm [J.P. Duguid, J. Hyg. 44, (1949) 471-479]. If these droplets get past the mask, they sink to the ground within a very short time due to their weight. From there they can be resumed and lead to infection.
A final assessment of which route of infection has which part in the infection process is still very difficult.
What changes with the appearance of the mutated viruses?
In the B. 1.1.7 variant of the virus, which is increasingly widespread in Germany, the structure of the spike protein is changed so that it can better interact with the receptors of the host cells. The key-lock principle works better, the virus can more easily penetrate the cells and convert them to virus production.
This also increases the likelihood of the smear infection, as fewer viruses now have to be transmitted for a successful infection.
This does not affect the effectiveness of PREVOSAN, as it attacks the unchanged envelope of the virus.