Scientists have determined when the risk of infection with corona is apparently highest. The delta mutation would significantly accelerate this effect again.
Munich – For well over a year, doctors and scientists all over the world have been puzzling over the origin and nature of the Sars-CoV-2 coronavirus. While the origin of the pandemic is still not clearly understood, there is at least new knowledge about the risk of infection. A current evaluation reveals two theses worth knowing in this regard.
Whether you are infected with a corona patient at all depends heavily on the point in time at which the contact took place. Scientists whose study results were published in the journal “JAMA Internal Medicine” came to this conclusion. The information results from a collaboration between Chinese health authorities in Zhejiang Province and US scientists, which sounds at least surprising in view of the political tensions in both countries. The question of whether the time of infection is related to the course of Covid-19 was also examined.
For the study, the spread of chains of infection was examined, which was based on 730 positive patients from January to July 2020. Of these people, 46 percent were mildly and around 43 percent moderately ill. On the other hand, around eleven percent of the infected subjects had no symptoms at all.
Corona infection: 730 infected people and to whom they passed the virus on and in what way
At the core of the analysis was the question of the extent to which the infected people mentioned passed the coronavirus on. From this, the data of a total of 8852 contact persons of the subjects concerned were determined. This analysis showed that infection was most often caused by the following factors:
- Conversations: 29.9 percent
- Living together in the same household: 16.7 percent
- Staying together in a closed room without direct contact: 15.6 percent
Of the thousands of contact persons identified (median age 41 years), 327 (3.6 percent) were infected with the above-mentioned index persons in the study. Of these, 61 people developed no symptoms at all. It seems to be important how severely the virus-transmitting person falls ill: As the researchers found, those affected who have been in contact with an asymptomatic corona patient are more likely to experience an identical course.
In addition, the study shows that the risk of infection from people with corona symptoms is four times higher than when infected people have a mild appearance. You can get infected with the coronavirus without noticing it. The course of the disease from Covid-19 can not only be weak, sometimes it is completely absent.
Corona infection: when the risk of infection is highest
The scientists found out when the risk of infection for contact persons was particularly high: the risk was most evident in the period from two days before the onset of symptoms to three days afterwards. Sars-CoV-2 spread particularly often on the first day of the symptoms. According to the study, this applies regardless of age, gender or other parameters with regard to the physical condition.
“These results have important effects on understanding the transmission dynamics of Corona,” is the conclusion of the scientific evaluation. The realization that the risk of infection is apparently highest two days before the onset of symptoms is emphasized. In the further course of the disease, the threat would allegedly be noticeably reduced.
Corona infection: why Delta should be more perfidious than previous virus variants
Another study from China comes to a similar result – and apparently attributes the development to the rampant Corona Delta variant. The thesis is expressed that earlier manifestations had a shorter time span between the infectiousness and the onset of symptoms.
The authors of the study from the University of Hong Kong write that around three quarters of the transmissions of the delta variant take place earlier before the symptoms begin. What then causes the increased risk of infection? Infected people do not yet know and feel nothing of their positive state and therefore pass the virus on more quickly because appropriate measures have not yet been taken.
Meanwhile, the current, fourth corona wave mainly affects two groups of people, as the RKI describes. (PF)
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