It is one of the most controversial questions of the pandemic: What role do children play in the transmission of Sars-CoV-2? A Canadian research team has now presented a new piece of work that contradicts some of the previous studies. The in Trade journal Jama Pediatrics published analysis suggests that young children are less likely to introduce the virus into their families. But if they do become infected, they pass the pathogen on more often than older children.
The scientists led by Lauren Paul from the Public Health Ontario health authority had evaluated all corona infections that occurred in the Canadian province of Ontario in the second half of 2020. They found a total of almost 6,300 households in which a child or adolescent brought the coronavirus home with them.
Analysis of this data suggests that the older they are, the more likely they are to introduce the virus into their families. 14 to 17-year-olds were responsible for 38 percent of the imported cases, whereas under four-year-olds were only responsible for twelve percent. It is plausible that older children get infected more often outside of the family, since they also have more contacts outside of the household.
However, when the researchers analyzed the consequences once the offspring were infected, the picture changed: Children between the ages of zero and three were 20 to 40 percent more likely to infect their relatives than older children.
An infected three-year-old cannot completely isolate himself
The authors do not give any reasons for this observation. In an accompanying comment, Susan Coffin and David Rubin, pediatricians at the University of Pennsylvania in Philadelphia, find it convincing nonetheless. They suspect that the behavior of the youngest plays a decisive role. It is difficult or even impossible to persuade small children to adhere to hygiene rules. Physical contact with parents and siblings is extremely important to them. If they are ill, they need more intensive care. A 17-year-old may be able to isolate herself reasonably well in her room. A three-year-old cannot do this.
Previous studies had suggested that younger children rarely transmit Sars-CoV-2. The two commentators explain the discrepancy primarily with the fact that the previous work comes from very early phases of the pandemic. At that time, families were largely in lockdown, and children were unable to show their potential as carriers. The current study, on the other hand, comes from a time when daycare centers, schools and other facilities were open and children led a less restricted life.
In the future, smaller children are likely to play a bigger role in the infection process, as they cannot currently be vaccinated. Lauren Paul and colleagues therefore urge you to take the new findings into account and to exercise as much caution as possible when caring for infected toddlers. Siblings should stay away from those who tested positive, masks should be worn and hands should be washed frequently.