It is the product of the hour. Those who want to buy disinfectants these days may find empty shelves in drug stores, supermarkets or pharmacies. The spread of the new Sars-CoV-2 coronavirus even leads people to steal disinfectants from hospitals. Where they are absolutely needed now. The bacteria and virus killers have long been offered online at absurdly high prices. And in some regions of the world, particularly those affected by the outbreak, cleaning personnel are spraying the agents even on the streets. There are now a number of instructions for making such remedies yourself. The Texas liquor maker Tito’s was even forced to via Twitter from using his vodka As an alcohol additive in hand-made hand disinfectants, it is not advisable: the alcohol content “does not correspond to the current recommendations of the American Centers for Disease Control and Prevention (CDC)”.
From a medical point of view, there are actually good reasons for the popularity of the vials, sprays and gels. A research group from the universities in Greifswald and Bochum has shown that Corona viruses (of which there are many different ones besides the pandemic Sars-CoV-2) can adhere to surfaces for several days. So they can also be infectious – but can be easily removed from there with disinfectant (Journal of Hospital Infection: Kampf et al., 2020). Especially disinfectants with an alcohol content between 62 and 71 percent can rid hands and objects of Sars-CoV-2 viruses and thus prevent pathogens from dropping from the nose and mouth onto surfaces, then onto hands and from there to the next organism become. Provided you use the right one – and you know when it makes sense to use it.
At least “limited virucidal”
Depending on where and against what they should work, the different types of disinfectants differ. Some are intended for the hands, others only for dry surfaces. Still others only work against fungi or bacteria due to their composition. They have the names “fungicidal” or “bactericidal”. However, if you want to protect yourself against the new corona virus, you have to make sure that the disinfectant is at least advertised as “limited virucidal”. Because uncoated viruses require different means than enveloped ones like the new corona virus.
The tiny pathogens have a simple structure – they essentially consist of a protein shell, the so-called capsid, and the genome, which is used to produce virus replicas in the host cell that are later to affect other cells. In addition to a protein shell, Sars-CoV-2 also has a lipid shell that is susceptible, not only for disinfectants – but especially for commercially available soap. On the other hand, fully virucidal disinfectants are required against some non-enveloped viruses such as hepatitis A or E, noro and rotaviruses. Many of these agents contain alcohol in different forms and concentrations – for example ethanol, isopropanol or benzyl alcohol – which irreversibly damages the protein envelope and the genetic makeup of the viruses and thus makes them harmless.
However, it is not always absolutely necessary to use disinfectants. Where and to what extent depends, among other things, on how likely it is that someone will become infected and how long the new coronavirus can survive on different surfaces. A number quoted by the media comes from the study by the universities in Bochum and Greifswald (Journal of Hospital Infection: Kampf et al., 2020): Human viruses of the Corona family can survive on metal, plastic or glass for at least two hours and up to nine days. However, the researchers had not examined the new Sars-CoV-2 coronavirus, but relatives from the same virus family, such as the viruses that triggered the Sars and Mers epidemics. In a study from the USA, which has so far been published without a scientific opinion, this was again specifically for the novel virus Sars-CoV-2 examined. The researchers came to a significantly lower result: the virus could survive two to three days on plastic and steel, and a few hours in the air (medRxiv: van Doremalen et al., 2020). However, this data is only considered to be secured if the study has been thoroughly checked by experts in this field.
Disinfecting everything privately does not make sense
For this reason, the Federal Institute for Risk Assessment (BfR) considers it conceivable that the new corona viruses can be transmitted by smear infection if the viruses reach the mucous membranes of the mouth and nose via hands. According to the institute, however, it does not make sense to regularly disinfect private households. “In general, human corona viruses are not particularly stable on dry surfaces,” says the institute’s website. To date, there have been no reports of food infections or contact with dry surfaces that could have been prevented by disinfection. According to the BfR, the stability of corona viruses in the environment depends on many factors, such as temperature, air humidity and the nature of the surface, as well as on the specific virus strain and the amount of virus. For example, UV radiation in sunlight and heat make the virus unstable.
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