Questions in the contact investigation and the lockdown

An important part in the question of how we can ever get rid of Covid 19 is “Who is How, When and Where is infected”. When you know that, you can tailor your measures to that very directly. Source and contact research is a very important tool that, in addition to numbers, can provide an idea of the extent to which the results of scientific research correspond to daily practice. Finally, a study in a laboratory, however carefully carried out, sometimes in practice it remains to produce different values.

The source and contact research started quite late in the Netherlands, suffered from many teething diseases and is still not immaculate today. Anyway, numbers are being announced. Often in beautiful pie charts or a field with different colored large and small balls. Sometimes accompanied by an explanation, but it is usually very brief. When I look at this with my ordinary housewives logic and compare it with the same kind of statistics from Germany, for example, I notice a number of things.

Firstly, these statistics are based on the number of infections and not on percentages within the different groups. It seems perfectly logical to me that in the “home” category there are many more people than, for example, in the category of “church and choir”, and the number of infections in “home” will almost automatically be much higher if you only look at numbers.

Secondly, almost all studies show that the category “unknown” is the largest. Usually about 3/4 of the total. But that does not automatically mean that the source of the infection is not or could not be known. In the first place, far from all cases are thoroughly examined. There are also people who do not want to participate in the source research at all. This is also difficult to find out from people who enter infected the Netherlands. Another strange phenomenon in the category “unknown” is that it is looked at very differently and also completely different conclusions are drawn from it. For example, I read in a Dutch report that a scientist stated that the infected people in that category would almost certainly NOT be infected at home because “they would know that anyway”. In my opinion, a strange conclusion when you consider that a lot of people are infected but have no symptoms. So it may well be that you get infected by a roommate. The German scientists of the Koch Institute come to a completely different conclusion. It is to be believed that at least a large proportion of people in the category 'unknown' have become infected in exactly the same way as those of whom it is known.

Thirdly, the category 'home' is taken very widely in the Netherlands. Literally everything you're home. The Koch Institute divides this out and considers people who stay in a hospital, care facility or shelter as a separate category. And then all of a sudden, big differences come to light. For example, it appears that people staying in a hospital or healthcare institution show a percentage much larger group of infected people. Even greater is the risk for people who are in a shelter. According to one of these August studies, 1 person infected an average of 3.2 people in his immediate vicinity at home. In the centres for the elderly there are 19, and in the reception centres 21.