immunity without being ill for nearly one in two children

Does immunity progress faster than you think? Two studies recently published in leading scientific journals suggest that many children have developed immunity to the virus without becoming infected with it. The first, published on November 6 in the magazine Science, estimates that 44% of children have developed effective antibodies against Covid-19 without even being infected. British researchers say exposure to other coronaviruses has led their bodies to develop an effective immune response against the novel SARS-CoV-2 coronavirus. The second study, presented on November 11 in the journal Nature Communications, says some children have developed an immune response as a result of their parents’ chronic exposure to the SARS-CoV-2 virus.

Children are better protected than adults

Exposure to other coronaviruses would protect nearly one in two children from infection with the novel SARS-CoV-2 coronavirus. The British researchers conducted a study on 302 minors, comparing the results of the blood of patients with the virus with those of volunteers who did not take it. They found that 43.8% of children and adolescents between the ages of 1 and 16 who did not contract the virus carry IgG antibodies that protect against Covid-19 infection.

Researchers believe these findings are important in the fight against the pandemic. “Our results show that children are much more likely to develop cross-reacting antibodies than adultscontinues Kevin Ng, author of the study. More research is needed to understand why, but it could be because children are more regularly exposed to other coronaviruses. ”

This additional research needs to show, in particular, why adults who have been exposed to other coronaviruses during their lifetime have not retained the antibodies that could protect them against Covid-19. Dr. Stephen J. Elledge, professor of genetics at Harvard Medical School, esteemed a New York Times that these antibodies and the memory cells that accompany them disappear over time.

No infections but antibodies

The family is believed to play an important role in the formation of effective antibodies against Covid-19 in children. Australian researchers from the Murdoch Children’s Research Institute (MCRI) have shown that continuous contact with parents infected with the virus led to their bodies developing these antibodies despite negative screening results in these children. The study authors looked at the immune profile of a Melbourne family of two parents with Covid-19 with symptoms and their three school-aged children. Samples of blood, saliva, nose and throat, feces and urine from the family were taken every 2-3 days. The researchers found specific antibodies against SARS-CoV-2 in the saliva of all family members and in detailed serological tests against healthy controls.

“The youngest child, who showed no symptoms, had the strongest antibody responseMCRI’s Dr. Melanie Neeland asked. Despite the active response of immune cells in all children, levels of cytokines, molecular messengers in the blood that can trigger an inflammatory response, remained low. This was consistent with their mild or no symptoms. “

The researchers suggest that this study shows that chronic exposure to the virus causes children’s immune systems to develop protective systems, in this case antibodies, to protect themselves from infection. “Studying immune responses to SARS-CoV-2 in all age groups is essential for understanding disease susceptibility, differences in severity, and candidate vaccines“Concluded Nigel Craworf, professor at MCRI.