For months we feared that the children were a "time bomb" in the COVID broadcast: we were wrong
From almost the beginning, one of the great unknowns of the virus was children. Even today they are. Wherever you look, regardless of the country or the continent, children are a striking minority of COVID-19 patients: between 0.3 and 5% of cases. And this is rare, especially if you look at other respiratory infections. The flu, to use the best-known example, annually hospitalizes more children under the age of 2 than people over the age of 65.
The researchers' response, of course, was that of mistrust. Wouldn't all this be the product of selective tests? I mean, aren't we looking bad? Were we really willing to believe that children were not contagious like adults? Despite all that went wrong? And the answer was no. The world prepared to close schools and send 1.5 billion children and youth home.
Now, with the certainty that the virus is here to stay and without being very clear on what to do with schools, we are beginning to have enough jobs to be able to give an answer to all these questions. Responses that are essential for the world to wake up from the state of cryogenization and regain activity. What happen with the kids?
Children get less contagion than adults
As is already commonplace in our knowledge of the coronavirus, these are all provisional conclusions. Until we have truly representative seroprevalence surveys of the world population, we cannot assure anything with complete certainty. However, that does not mean that we cannot dive into the available evidence and realize that there are very strong trends around all of these issues. We do not have a defined image, it is true, but the contours are beginning to be seen clearly enough to know which pitch we are on. Especially in the field of transmission.
To conclude that children are infected less than adults, we have two lines of work. The first has to do with studying household contacts to see how households behave once the virus enters them. Along these lines, we have two recent studies (I and II) that found that children are half as likely to be infected as adults. There is also a Swiss study that puts that probability at 32%.
They are very different populations (Israeli, North American and Swiss) and have had different exposures to the pandemic. However, most studies were done with PCR and some experts have suggested that one of the causes of underdiagnosis in children is that they did not 'store as much viral amount in the nose' and, therefore, swabs were not an effective method for pediatric studies. Fortunately, they also did a study in the Netherlands (although this time they were serologies) with very similar results: 50% less likely to be infected.
In summary, the studies show quite consistently that children become less easily infected than adults, and, as a logical consequence, sero-epidemiological surveys find few children with antibodies. This is also evident in one of the few meta-analyzes that have been done on the subject and that uses the second line of work: going beyond the domestic sphere. When choosing this approach, their results are more conservative, but they still find that the risk of infection in children is 44% lower than in adults.
Are they super-contagious? Are schools a danger?
Also due to the 'contagion' of influenza where they are very important vectors, another central issue in the field of transmission is the role that children play in the transmission of the virus. The reason is simple: although they are less contagious, if, as they said at the beginning of the pandemic, they are 'super-contagious', schools are still very problematic places. But it is not what we are finding.
Evidence on this topic is scarcer. Above all, because the massive closure of schools has prevented us from studying this phenomenon in detail (and because the few countries that did not close them have not studied it adequately). However, the data we have so far seems to suggest that they also spread significantly less than adults. For example, the same Dutch study we were talking about earlier tried to find the most likely origin of those infected and found that according to national records, the majority of cases appeared to be from adult to adult. The other two options (child to adult or adult to child) had minimal impact on broadcasts.
In other words, at the outset, it seems that we can advance in the de-escalation of the educational system without the risk being triggered. Of course, the uncertainty will not last us too long: we will have data very soon. Dozens of countries are reopening (and re-closing) their schools right now trying to find the perfect balance that will help them revive the education system. Summer in the northern hemisphere works in our favor, but if we don't prepare any conclusion, no matter how quickly it comes it may be late.
Image | National Cancer Institute