In a new study, researchers found that children are protected from severe COVID-19 because their innate immune system is quick to attack the virus.
They found that specialized cells in a child’s immune system rapidly target the new coronavirus (SARS-CoV-2).
The research was conducted by a team the Murdoch Children’s Research Institute (MCRI).
Children are less likely to become infected with the virus and up to a third are asymptomatic, which is strikingly different to the higher prevalence and severity observed in children for most other respiratory viruses.
In the study, the team did an analysis of blood samples from 48 children and 70 adults across 28 Melbourne households infected with or exposed to, the new coronavirus.
Immune responses were monitored during the acute phase of infection and up to two months afterward.
Francesca Orsini and Alessandro Bartesaghi took part in the study along with their two daughters, Beatrice and Camilla, after all tested positive to COVID-19.
Both daughters, aged six and two, only had a mild runny nose but Francesca and Alessandro had extreme fatigue, headaches, muscle pain and loss of appetite and sense of taste.
It took Francesca and Alessandro at least a fortnight to fully recover.
The study showed that children with COVID-19 have a more robust innate immune response to the virus compared to adults.
Coronavirus infection in children was characterized by activation of neutrophils, the specialized white blood cell that helps heal damaged tissues and resolves infections, and a reduction in first-responder immune cells such as monocytes, dendritic cells and natural killer cells from the blood.
This suggests these infection-fighting immune cells are migrating to infection sites, quickly clearing the virus before it has a chance to really take hold.
The find shows that the innate immune system, our first line of defense against germs, is crucial to prevent severe COVID-19 in children.
Importantly, this immune reaction was not replicated among adults in the study.
The research stated although the children had been infected with the coronavirus, they were able to mount an immune response which was highly effective in stopping the virus from replicating, meaning they never returned a positive test.
One author of the study is MCRI’s Dr. Melanie Neeland.
The study is published in Nature Communications.