CHILDREN are less likely to get infected with COVID-19 and appear to suffer milder cases of coronavirus, studies have found — with some having no symptoms at all.

A paper, published in the journal Pediatrics, looking at the severity of symptoms in 2,134 children in China suspected to have COVID-19, found the effects of the infection were less serious than has been seen in adults.

Some 4 percent of children had no symptoms at all. Just over half, 51 percent had a mild illness, and the condition was moderate for 39 percent of the cases. The remaining 6 percent were in the severe or critical level for the condition. By comparison, for adults in China around 18.5 percent of cases were severe or critical.

Now scientists have suggested that children may be resistant because their immune systems are already well primed by the common cold.

The common cold is caused by four different types of coronavirus which circulate in the community and are largely harmless. But while adults pick up a cold around two to four times a year, school age children catch an average of 12 colds annually, studies have shown.

Professor John Bell, Regius Professor of Medicine, University of Oxford said that it may allow youngsters to build up some ongoing resistance that adults do not have.

“How you respond may be due to the state of your existing immunity to coronaviruses generally,” he said.

“There is an interesting speculation at the moment, that suggests that many people in young or middle-aged groups may have T-cells that can already see coronavirus. It may well be able to provide some protection against this pathogen when it arrives.

“A lot of kids get seasonal coronaviruses and it’s pretty common in our population and many will have quite a strong immunity to coronaviruses generally.

“That is unproven, but there is evidence now for cross-reactivity at T-cell level at least, and that well might help dampen the effects of the virus when we get it.”

Studies have shown that by the age of 4, some 70 percent of children already have antibodies against seasonal coronavirus, which could offer important protection.

Professor Adrian Hayday, Chair, Department of Immunobiology, King’s College London said the immune systems of young people may simply be better at reacting to new viruses.

“All adults past a certain age — 30 to 35 — eventually have no thymus so their T-cells work by looking at whether they have seen something before, whereas children are very good at seeing things that are completely unknown.

The scientists also said that older people may suffer from immune cell “senescence” where their immune cells start to shut down but are not cleared away and replaced with a working version.

Bell said for most people coronavirus was not a serious illness.

“The people who get severe disease and die, the vast majority are elderly people and when young people get this disease they tend not to suffer very much.

“That might be the state of people’s immune system at different ages. The vast majority of people who get this disease don’t even know they’ve had it.”(SD-Agencies)