According to a new German study carried out in one of the centers of the pandemic, one in five Covid patients would not show any symptoms.
- The fact that some people infected with the coronavirus show no symptoms is one of the characteristics of the Covid-19 epidemic
- According to a new German study, one in five patients with Covid-19 would be asymptomatic
It has already been known for a long time that some people infected with the coronavirus do not feel any symptom, hence the difficulty of stopping the spread of the virus. According to the US Centers for Disease Control and Prevention (CDC), a quarter of those infected are asymptomatic. According to a new study carried out in Germany, in one of the main centers of the pandemic, the ratio would be precisely one in five people.
Here, a team of researchers from the University of Bonn (Germany) studied the cases of the 919 patients identified in Ganglet, a locality of approximately 11,000 inhabitants located in the district of Heinsberg. In Gangelt, about 15% of the population has been infected. Among these patients, the death rate reached 0.37%.
“If we extrapolate this figure to 6,700 deaths associated with Covid-19 in Germany, the total number of infected people would be estimated at around 1.8 million.”, note the researchers, a number “ten times the total number of officially reported cases”. In conclusion, “in Gangelt, 22% of those infected showed no symptoms”.
Anyone who is supposedly healthy can carry the virus.
On the other hand, the researchers noticed that the infections within the same family were quite low. Generally, the infection rate appears “very similar in children, adults and the elderly and apparently not dependent on agenor sex, they note.
“The fact that apparently one in five infections proceed without visible disease symptoms suggests that infected people who shed the virus and can therefore infect others cannot be reliably identified on the basis of recognizable symptoms of disease.”, explains Professor Martin Exner, co-author of the study, to AFP.
According to him, these results confirm the importance of the rules of social distancing and hygiene. “Any supposedly healthy person we meet can carry the virus and not know it. We need to be aware of this and act accordingly.”, explains the researcher, while Germany has begun a progressive deconfinement.
Further investigations still need to be carried out on the subject. “To determine whether physical proximity to other participants and increased droplet formation through loud talking and singing contributed to a stronger disease course, we are planning further cooperative investigations.”, conclude the researchers.
Symptomatic contagious patients before the appearance of clinical signs
It should also be remembered that even people who develop symptoms of Covid-19 (fever, dry cough, respiratory problems, body aches, loss of smell or taste, etc.) are contagious without their knowledge since they are so well before the appearance clinical signs of the disease.
According to a study conducted on Chinese patients, infectiousness begins on average 2.3 days before symptoms appear, with the peak of contagion 0.7 days before the onset of symptoms and decreases rapidly during the first seven days. Among the secondary cases observed during the study in the chain of transmission, 44% were infected during the period preceding the onset of symptoms.
This information thus calls into question population control measures, in particular applications for tracing people in contact with a positive case. “More inclusive criteria must be taken into consideration in contact tracing in order to identify potential modes of transmission two or three days before the onset of symptoms and thus be able to control the epidemic more effectively”noted the authors of this study.
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