23-10-2020 by Mirai
Tracking people at the source of contaminations, in addition to the contact cases of people who tested positive for Covid-19, would be effective in combating the epidemic. This is called backtracking or "Japanese tracking." But what is the goal of this strategy?
To contain the Covid-19 epidemic, it is the "trace, test, isolate" strategy that is applied in several countries. When a person tests positive for Covid-19, they trace their contacts and these identified contact cases are also tested and isolated, allowing the chains of contamination to be broken. This is called forward tracking.
What if we also looked for the people who infected the source case that tested positive for Covid-19? This strategy, called backtrace or "Japanese trace" and applied in Asian countries such as Japan, appears to have proven effective. "Looking up is more important than looking down," says German virologist Christian Drosten.
Identify the super spreaders of the virus and the places of contamination.
What is the purpose of this system? According to several studies, it would identify the "super spreaders" of the virus, but also the places of contamination. And for good reason: most people affected by Covid-19 infect almost no one, but 10% of positive cases are responsible for 80% of transmissions. These are called "super propagators". Therefore, it is more likely that a person affected by the virus has been infected with one of them.
Tracing the chains of contamination would therefore allow them to be identified, to prevent them from transmitting the virus to other people, but also to go in search of people with whom they have already been in contact. "If a person transmitted the virus to me, the probability that they will transmit it to many other people is very high. That is what interests me," sums up Antoine Flahault, epidemiologist and director of the Institute for Global Health at the University of Geneva.
This strategy would also make it possible to identify places of contamination. "By mapping patient interactions before they become infected and matching them with those of other infected patients, screeners can identify common sources of infection: the people and places in the home of the cluster," said Yasutoshi Nishimura, Minister of Economic Revitalization in charge of fighting the virus, in the Wall Street Journal.
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