THURSDAY, February 18, 2021 (HealthDay News) – Children have largely been spared a serious infection with COVID-19, and new research shows why.
In the study, the immune system of children attacked the novel coronavirus faster and more aggressively than the immune system of adults, the results showed.
The researchers analyzed blood samples from 48 children and 70 adults who lived in 28 households in Melbourne, Australia, and who were infected or exposed to the coronavirus. The participants’ immune responses were assessed during the acute phase of infection and up to two months afterwards.
Children had a stronger immune response to the virus than adults, according to the report published online Feb. 17 in the journal Nature’s communications.
“Coronavirus infection in children was characterized by activation of neutrophils, the specialized white blood cell that helps heal damaged tissue and resolve infections, and a reduction in first responder immune cells such as monocytes, dendritic cells and natural killer cells in the blood, ”said study author Melanie Neeland of the Murdoch Children’s Research Institute.
“This suggests that these anti-infective immune cells migrate to the sites of infection, quickly clearing the virus before it has a chance to really take hold,” she said in a press release from the institute.
The results showed that “the innate immune system, our first line of defense against germs, is crucial in preventing severe COVID-19 in children. Importantly, this immune response has not been replicated in adults in the study, ”Neeland said.
The researchers also found that children and adults exposed to the coronavirus, but tested negative, also had altered immune responses.
“Children and adults had increased neutrophil counts, up to seven weeks after exposure to the virus, which could have provided a level of protection against the disease,” Neeland said.
So far, it has not been clear why children tend to have milder COVID-19 than adults, researchers say.
“Children are less likely to be infected with the virus and up to a third are asymptomatic, which is remarkably different from the higher prevalence and severity seen in children for most other respiratory viruses,” said declared Neeland.
“Understanding the underlying age-related differences in the severity of COVID-19 will provide important information and opportunities for prevention and treatment, both for COVID-19 and possible future pandemics,” said she added.
The American Academy of Pediatrics has more on COVID-19.
SOURCE: Murdoch Children’s Research Institute, press release, February 17, 2021