Are certain people potentially more contagious than others? A study by virologist Christian Drosten examined this. The researchers have also been able to determine when the viral load and thus the possible risk of infection are at their highest.
A Charité research team led by Dr. Christian Drosten determined the amount of virus genetic material in the PCR sample in around 25,000 Covid 19 cases in order to estimate the contagiousness of the people who tested positive . The R value says how many people an infected person infects – on average around three to five other people. However, it has no significance whatsoever as to how high the probability of transmission is in an individual case or in certain population groups. Because people can be contagious to different degrees or shed corona viruses over a short or long period of time.
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Children have lower viral loads than adults
When analyzed by age group, no significant differences in viral load were found among those infected between the ages of 20 and 65. Lower viral loads were found in samples from children between the ages of 0 and 5 years; in older children and adolescents, the values approached those of adults with increasing age.
High viral load three days before symptom onset
Very high viral loads were also found in infected people who did not show any signs of corona disease. In people who had to be treated in the hospital, the viral load was higher over the entire course than in other people tested. The researchers estimate that people with Covid-19 have the highest viral load in their throats one to three days before the onset of symptoms . “The fact that there are so many people among them without relevant symptoms of illness makes it clear why measures such as distance rules and the obligation to wear masks are so important for controlling the pandemic,” said Christian Drosten. The British virus variant was also detected in the samples examinedfound with a tenfold higher viral load. “Even if laboratory tests have not yet been able to explain it conclusively: the B.1.1.7 virus is more infectious than other variants,” says Drosten.
