Children could be as contagious as adults: German virologist Christian Drosten had attracted a lot of attention in 2020 with this conclusion based on initial data from people infected with Corona. Based on a now broader database, does the virologist stick to his guns?
After the publication of his Corona study in the renowned journal “Science”, virologist Christian Drosten sees himself confirmed in his assessments of the infectiousness of children as well.
“My initial impression of an approximately equal infectivity of all age groups has been confirmed, not only here, but also in other studies,” said the expert on coronaviruses, according to a Charité release. He reiterated in the “Coronavirus Update” on NDR-Info: Based on initial data, one had seen as a clinical virologist that everyone had approximately the same amount of virus. This impression has held.
Drosten says viral load allows prediction of infectivity
For the study now published, scientists led by Drosten determined the so-called viral loads, i.e., the amount of viral hereditary material in the PCR sample, for more than 25,000 covid-19 cases. “The hereditary copies approximately represent the amount of virus in the throat of the patients and therefore allow predictions about their potential infectivity,” Charité explained. Multiple samples were available from more than 4,000 cases, allowing conclusions to be drawn about the course of the infection. The study included infected persons without signs of disease as well as patients with symptoms of varying severity, up to and including hospital cases.
Adults between 20 and 65 years of age showed “no significant differences” in viral load, according to the Charité release. The lowest viral loads were found in samples from the youngest children between 0 and 5 years of age, it said. And in older children and adolescents, the values had converged with those of adults with increasing age, it continues.
Drosten believes that the values for children are influenced by a different type of sample collection compared to adults: significantly smaller swabs are used, which bring in less than half as much sample material. In addition, instead of the painful deep nasopharyngeal swabs, simple throat swabs are often taken, in which even less virus is found. Therefore, lower readings are to be expected in children from the outset, he said.
Great debate about first Drosten study on viral load
Drosten had already presented the first evaluations on viral loads, which had not yet been examined by independent experts, more than a year ago. The conclusion that children could be as contagious as adults had received much attention in the debate about opening schools and kindergartens. The current publication is much more comprehensive. It is now probably the largest study ever on the subject, Drosten said. It will also be continued.
The study also supports the assumption that a relatively small proportion of those infected are responsible for a particularly large number of infections. As Drosten described, there are infected people in all age groups, including children, with exceptionally high viral loads. In the study, this affected about nine percent of the cases studied. According to the virologist, a “considerable number” of these are people who develop at most mild symptoms throughout the course of the disease. People without signs of disease were also among them, he said.
Considering the risk of infection from healthy-seeming infected individuals, the researchers emphasize the importance of measures such as social distancing and mask-wearing in their conclusion to the study. “The peak of virus shedding is one to three days before symptom onset,” Drosten said of another finding of the work. That’s why the virus is so difficult to control, he said. And another thing that was striking, he said, was that “the people who get severely sick later have a lot of virus consistently even at the beginning.”
Further, the study shows that people infected with the B.1.1.7 variant discovered in the United Kingdom appear to be more contagious than infected people with other variants. Their viral loads are increased by a factor of 10 in comparison, Drosten said. That is substantial, he said.
Sources: fitboot.com and dpa/picture: pixabay.com
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