What can toddlers do better than adults

Coronavirus: What We Know About Childhood Transmission

Analyzes of the viral load in the throat show that children seem to have about as much virus in their throat as adults. In an American study, young children who developed symptoms actually had more viral RNA in their throats than adults. Experts believe that symptomatic children can transmit the virus just as effectively as adults. However, it is unclear whether children without symptoms are just as involved in the spread.

A big problem is that specific infection rates cannot really be researched in controlled experiments because you would have to consciously infect people. That is not ethically justifiable. That is why researchers only have the option of looking at outbreak events retrospectively and using them to determine infection rates.

Initial analyzes of outbreaks among children

There are a few studies that look at outbreaks in which children were also involved. One study comes from Australia and looks at multiple outbreaks in schools and childcare facilities in New South Wales. It was clear here that the incidence rates were highest among adults (4.4 percent) and lowest among children (0.3 percent). The incidence rate when adults infected children was 1.5 percent. If a child brought the virus with them, the disease rate for adults was one percent.

Two other studies from France looked at outbreaks in six elementary schools and one high school and also included the contact persons in the households. Here, too, children had rather low infection rates compared to adults. But: Among adolescents aged 12 to 15 years and older, the researchers observed significantly higher infection rates than among adults.

In these studies, however, one must bear in mind that the results do not come about under controlled conditions and can only be transferred to other situations to a limited extent.

Larger outbreaks in holiday camps than in schools

How infectious children are or how easily they can catch the coronavirus also seems to depend on the setting. Researchers from the United States took a closer look at an outbreak at a vacation camp in the state of Georgia. A supervisor there had developed symptoms, left the holiday camp the next day and had himself tested for SARS-CoV-2 another day later. The test was positive. It then took another three days until the holiday camp was closed and all the children and carers were sent home. Enough time for the virus.

Then 44 percent of all participants in the holiday camp - 260 out of 597 people - tested positive. The infection rate was almost always the same: Among the 6 to 10 year olds it was 51 percent, among the 11 to 17 year olds it was 44 percent. Only among 18 to 21 year olds was it 33 percent.

The results from the schools and the holiday camp are quite different, but they show that even among children, infection rates can skyrocket, depending on the environment. It generally looks like the virus is more easily transmitted between adults. But it also becomes clear: the closer the contact between the children - for example in a holiday camp with overnight stays in shared rooms, singing and a relaxed atmosphere - the more likely the virus will spread just as unchecked as among adults.

The risk of infection varies

"The risk of infection from children depends on the contact and the hygiene measures," says Ulrike Protzer. She suspects, which studies also confirm: that an infected child is also very likely to infect his parents and siblings. What is surprising in children is that viral RNA was even able to be detected in stool samples - even well beyond the quarantine period. "It is not yet possible to say whether this is contagious."

In addition to the infectious viral load in the throat, there are other influencing factors that must be weighed up against each other: If children often only have very mild symptoms or no symptoms at all, the risk is lower that they will spread many droplets with viruses by coughing or sneezing - and thus infect others. On the other hand, children often have closer physical contact and touch each other's faces more often.