Researchers have found that children were immune against Covid-19, without having been infected initially. Several scenarios could explain this fact. One of the studies on the issue, published in the journal Nature communications, reveals that specialized cells of the children’s immune system quickly target the novel coronavirus. And that their innate immune response is more robust against the virus than that of adults. “This shows that the innate immune system, our first line of defense against germs, is crucial in preventing severe COVID-19 in children, ”the researchers point out.
Another study, this one British, compared blood samples from children between 1 and 16 years old. Out of 302 people, some had the virus, others had never caught it. Corn on the sample of those who had never had it: 43.8% had the antibodies, underlines the review Science. Their conclusions are based on the fact that the children would have been exposed to their sick parents, to the point of seeing their immune system develop.
An immune response motivated by overexposure to the coronavirus
Each study has its conclusions, but the two converge nonetheless. The first explains this immunity by intense and chronic exposure to SARS-CoV-2, which would be enough to trigger the immune process to fend off the disease. The second estimates that the children would have been in contact with other coronaviruses, which would have activated their immune system. As a result, they had the defenses necessary to protect themselves from a SARS-CoV-2 infection. We are talking about cross immunity.
While this causal link is true in the children studied, it is not for everyone. Most often immunity develops after contracting and developing Covid-19. Some even catch it repeatedly because their immune system fails to fight off reinfection. In addition, if these studies could give hope to see the development of a collective immunity more quickly, remains that the samples of these studies are very limited.
Sources:
- Innate cell profiles during the acute and convalescent phase of SARS-CoV-2 infection in children, Nature communication, February 17, 2021
- Preexisting and de novo humoral immunity to SARS-CoV-2 in humans, Science, December 11, 2020
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