In the lungs, a final, non-specific defence mechanism against viruses is provided by scavenger cells in the immune system, which are found in the alveoli. These cells are responsible for keeping the lungs clean; in doing so, they don’t distinguish between pathogens and pollutants from the environment. But their capacity to gobble up particles is limited. The more time they spend removing fine dust and other particles from the alveoli, the less efficient they are at reducing the number of viruses.

Measures to reduce the number of viruses

It is important to realise that we do not necessarily become infected as soon as we inhale a virus. The probability of infection increases with the number of viruses, which means that the dose of viruses is critical. Breathing only through the nose already reduces the number of viruses that enter the mouth region. Once they have entered into our body, at least some of the viruses that get stuck on the lining of the throat might get removed when using antiviral mouthwashes, of which a wide variety is available. Common home remedies that we typically use to fight early symptoms of a flu infection, such as gargling and drinking hot ginger tea, are fully justified too. Regular inhalation of water vapour further helps to keep the mucus layer in our respiratory tract sufficiently fluid, which in turn helps the conveyor belt to clean out particles more efficiently. Finally, to allow the scavenger cells in the alveoli to fight off viruses as efficiently as possible, it helps to avoid exposure to other environmental pollutants such as particulate matter, and to give up on smoking.

Taking small, additional actions can help to further reduce the number of viruses that enter our lungs, and you can help at several levels: from the nose, throat and bronchial tubes all the way to the alveoli. And it is this number of viruses, again, that determines whether a severe lung infection might occur or not. We are not helpless against the coronavirus. Each and every one of us can do our bit to keep it in check.

Amendment dated 16.03.2020

Dear Readers,

I deeply appreciate the many reactions. Because of the large number of comments, I have decided not to answer each and every one of them, but to provide answers collectively.

I would like to emphasize that I am a scientist and not a physician. Therefore, I will not give specific therapeutic suggestions, but will rather try to explain mechanisms that we might be able to exploit.

Many details about the behaviour of the new coronavirus are not yet known. As soon as we gain new insights, these will continuously refine the methods of fighting the pathogen. However, we must be aware that this may take some time.

The effectiveness of social distancing and hand hygiene measures are well known. In my Zukunftsblog contribution I pointed out that respiratory hygiene could also be important. Many of you are now asking for specific recipes and products in this regard. Some have also suggested their own recipes. As the knowledge about the current pandemic pathogen is still limited, I would like to comment only about mechanisms in general, but not on specific recipes.

Coronaviruses – like the influenza (flu) virus – are surrounded by an outer layer (membrane) that contains a large proportion of lipid molecules. All substances that destroy lipid membranes destroy these viruses too. This means they have an antiviral effect.

Soap is one of these substances. This is why it is so important and effective to carefully wash our hands with soap. Toothpaste also contains surfactants which are able to destroy lipid membranes. It could therefore be effective if we gargle with the foam remaining in our mouth after brushing our teeth. However, I am not aware of any scientific literature on this.

As far as plant substances are concerned: many plants produce a range of natural substances to protect themselves against pathogens (including plant viruses). Ginger, for example, contains phenolic compounds which have been shown to have antiviral activities, whereby some of their ingredients might again perturb the lipid-rich envelope of certain viruses.

Because of the structural similarities between corona and influenza viruses, plant compounds used to alleviate the early symptoms of flu infections could possibly also help to alleviate the course of a COVID-19 infection. However, this is speculation.

Please stay healthy and take care by protecting yourself and others.

Viola Vogel