Covid 19 coronavirus: Children's immune systems better equipped to deal with virus

The immune systems of children react to the novel coronavirus more rapidly than the immune system of adults, meaning they are affected much less severely by the disease, new research has shown.

A new study published in Science Translational Medicine shows that the immune system of children is evolved to protect the body against unfamiliar pathogens by rapidly destroying them before they have the chance to harm the body. In the more developed immune system of adults, the response to new pathogens, such as SARS-CoV-2, is muted.

When the human body detects a foreign pathogen, an innate immune response is triggered, whereby the immune system begins to attack and overwhelm the invader. Children are more likely to encounter pathogens new to their immune system, meaning their innate defence system responds more quickly.

Children wearing face masks read the Quran at a religious school in a mosque, in Karachi, Pakistan. AP Photo / Fareed Khan, File

"The bottom line is, yes, children do respond differently immunologically to this virus, and it seems to be protecting the kids," said Dr Betsy Herold, a pediatric infectious disease expert at New York's Albert Einstein College of Medicine who led the study.

Over time, the body builds up a "memory" of known threats. This means that when adulthood is reached, the immune system is evolved to respond in a more targeted way. As we age, our innate immune response fades.

Speaking to the New York Times, Dr. Michael Mina, a pediatric immunologist at the Harvard T.H. Chan School of Epidemiology in Boston, said the adaptive system makes sense biologically, because adults rarely encounter a virus for the first time.

However, the virus that causes Covid-19 is new to humans, meaning an innate immune response is the most effective way to combat the threat it poses. By the time the adaptive immune response has begun, the damage caused by the virus has already occurred, according to Dr Herold's research.

The study involved examining the immune response of 60 adults and 65 youngsters under the age of 24 who had been hospitalised with Covid-19 in New York City.

It found that the younger cohort were much less likely to suffer severe symptoms. Only five children needed ventilation with two dying, compared to 22 adults needing medical ventilation, resulting in 17 deaths.