Coronavirus: meeting supercontagators helps fight pandemic

The more we investigate about the new coronavirus, the more we know about its forms of contagion. That is basically a positive thing, because, in this way, you can fight the pandemic more effectively, but, at the same time, some of the measures taken at the beginning of the crisis seem to us, in retrospect, to be ineffective or unnecessary .

Who are superchargers?

Epidemiologists call a person who transmits the infection to many people a supercontainer. It is something that cannot be avoided: anyone who carries the virus can become a super-contagious if they have contact with many people at the wrong time. The point of infection you are at is also decisive, as some people can be very contagious before the first symptoms appear.

In fact, many infected have little or no symptoms at all, so they don't realize they carry the virus and are highly contagious. To all this we must add that some people can transmit more viruses for longer than others. It is possibly something to do with your immune system and the way the virus receptors are distributed in your body.

How does an infection cluster happen?

If a supercontainer matches many people, it can infect more individuals than the usual average in a very short time and in a very specific place. This type of cluster of infections has taken place worldwide. One recently took place in Germany during a large family celebration in Göttingen, as well as during a religious service in Frankfurt and at a carnival party in Heinsberg.

In Seoul, there was a cluster of infections in nightclubs and on a zumba dance course. At the well-known ski resort of Ischgl in Austrian Tyrol, there was also a focus of contagion, as well as on several cruises around the world and at slaughterhouses in the German region of North Rhine-Westphalia.

Transmission through aerosols?

Research into these types of supercontag events has shown that there are some factors that appear to favor the rapid spread of infections. Basically, it can be said that the risk of infection is clearly higher indoors than outdoors. And the more people who meet, the greater the risk of contagion.

But why? Signs appear to be accumulating that the virus is transmitted not only through fluids, but also through aerosols, which remain in the air longer than heavy drops, especially in small, poorly ventilated spaces.

Research into super-tag events also shows that aerosols spread the louder the louder or even the louder they are, for example in bars, nightclubs, or gyms. The same principle applies to singing, whether in choir or during religious services. In that activity, some people produce more sprays than others.

Risk calculation

How stringent pandemic measures must be depends largely on the number of new infections. In this sense, the so-called basic reproductive number is decisive, that is, how many people on average does someone infect with the virus. A basic reproductive number of 2 means that an infected person infects two other people.

The objective of social restriction measures is to lower the basic reproductive number as much as possible. If possible, keep it below 1. In addition to this indicator, we have the so-called dispersion factor k, which indicates how often the disease appears and where clusters of contagion can occur. Here, too, the ideal is to keep the value as low as possible, because that means that the spread is less and the spread of the infection can be attributed to a few people or even just one.

Akira Endo, Adam Kucharski and Sebastian Funk of the London School of Hygiene and Tropical Medicine conclude that the dispersion factor k could be as low as 0.1 percent in a recent study that has received a lot of attention. . According to the work, which is yet to pass the peer review, 10 percent of those infected could be responsible for 80 percent of the infections.

What are the implications of all this?

Research into the new coronavirus has been done under enormous time pressure and politicians have made decisions about how to protect the population based on it. The debate on the first rejected and now mandatory face masks clearly reflects that decisions must be adapted to new discoveries, although some people do not understand it or do not want to understand it.

Research so far shows that most infected people spread to very few people. That is, in principle, very good news, because that way more effective decisions can be made to contain the pandemic. For example, if large congregations of people are banned, especially indoors, and hygiene and separation rules are followed, it will be easier to contain the spread of the virus. The whole of society will not have to be paralyzed, with the well-known dramatic social and economic consequences.

Source: DW