The ‘Swiss cheese model’ illustrating the most effective fight against the coronavirus: masks or social distance?

Masks, social distancing, hand hygiene, hydroalcoholic gel, surface cleaning … What is the most effective measure against the coronavirus? The answer to the question is all together. And this is illustrated by the so-called ‘Swiss cheese model of accident causation or cumulative effect model’. You may wonder, what do dairy products have to do with the pandemic that affects the whole world? Well, nothing really. But the famous holes that Gruyère cheese presents graphically illustrate how the most efficient fight against Covid must be.

Thus, if we propose each of the security measures against the coronavirus as a slice of Swiss cheese, with its characteristic holes, and we superimpose them, we will understand that each measure alone has flaws but all of them together act as an insurmountable network for the virus that causes Covid. Each measure is a slice of Swiss cheese and their respective holes are their faults. That is, in the case applied to the coronavirus, the viruses that creep through the security flaws of each measure are absorbed by the success in each of the subsequent layers. Thus, masks By themselves they will not make the coronavirus disappear because they are not 100% effective. In the same way, the hydroalcoholic gel It is effective if every part of the skin is impregnated with the liquid every time you clean your hands. Without forgetting any. Something that may not be fulfilled 100% of the times it is used. And following the same logic, the social distancing stricter if it could stop the contagion of coronavirus but the human being is gregarious by nature and we live in a society in which total isolation is not on the table. In short, each anti-Covid security measure by itself is not going to get the world out of the pandemic, but the integration of all of them in a system could.

The Gruyère cheese model is widely used in risk analysis and management, both in engineering and health. Applying the concept to the current pandemic, various virologists have talked about what the most effective combination of measures would have to be to end the coronavirus. They distinguish between those that respond to individual responsibility and those that respond to a collective and of the governments.

Among those that are in the hands of each citizen to comply are social distance, the use of regulated and effective masks, hand hygiene, avoid touching the face and staying as short as possible in crowded and closed spaces.

As for the measures that would respond to a collective conscience, there are tests and a complete and exhaustive search; ventilation and installation of air filters; economic support for the population by the Government and effective communication; isolates and quarantines and, finally, the vaccine that could immunize citizens against the coronavirus.