Children have a highly effective immune response that protects them from being infected by the novel coronavirus or suffering from severe symptoms, according to a study conducted by the Murdoch Children's Research Institute (MCRI). Experts discovered that specialized cells in children's innate immune systems attack the coronavirus and prevent it from spreading rapidly once a child is infected.
Dr. Melanie Niland stated that before this study, the underlying reason for children's immunity or their experience of mild symptoms upon infection with the coronavirus, compared to adults, was not known. This study identified for the first time the immune mechanisms that provide protection to children against the disease. She added, "Children are less likely to get infected with the virus, and up to a third of them show no symptoms at all, which is notably different from the high prevalence and severity of symptoms observed in most respiratory viruses in adults. Understanding the fundamental age-related differences will provide important insights and opportunities for prevention and treatment for both coronavirus and potential future pandemics."
During the study, researchers analyzed blood samples taken from 48 children and 70 adults from 28 families in Melbourne, all of whom were infected with the coronavirus. The immune responses of family members were monitored during the acute phase of infection and up to two months after recovery. In one specific case, four family members tested positive for the coronavirus. While the parents exhibited severe symptoms of extreme fatigue, headache, muscle pain, and loss of appetite, their children only experienced mild nasal congestion.
Dr. Niland further added that this study showed that children infected with the coronavirus have a stronger innate immune response to the virus compared to adults. The COVID-19 infection in children was characterized by the activation of neutrophils, which are specialized white blood cells that help heal damaged tissues and eliminate infections, alongside a reduction in the first-responder immune cells such as monocytes, dendritic cells, and natural killer cells in the blood. This indicates that these infection-fighting immune cells move quickly to the sites of infection and eliminate the virus before it has the chance to replicate or spread within the body.
