Children may have greater protection against coronavirus because they pick up so many colds, research suggests.
The study found children are eight times more likely than adults to naturally have antibodies that help fight off Covid-19 despite never having had it.
Research by the Francis Crick Institute found that 44 per cent of under-16s but only five per cent of adults have “cross-reactive” antibodies which offer some protection from Covid.
The antibodies come from exposure to common colds, which come from the same family of coronaviruses, but adults are less likely to develop them despite coming into contact with the same bugs.
The study of 300 blood samples, collected before the pandemic, helps explain why children are significantly less likely to catch or fall ill with Covid.
Lead researcher Kevin Ng, of the Crick Institute, said: “Our results show that children are much more likely to have these cross-reactive antibodies than adults. More research is needed to understand why this is, but it could be down to children being more regularly exposed to other coronaviruses.
“These higher levels we observed in children could also help explain why they are less likely to become severely ill with Covid-19. There is no evidence yet, however, that these antibodies prevent SARS-CoV-2 infection or spread.”
The findings, published in the journal Science, show the cross-reactive cold antibodies help neutralise Covid-19.
Just 22 people under the age of 20 have died of Covid in England out of 34,091 hospital fatalities.
Researcher George Kassiotis, also from the Crick Institute, said the protection from antibodies caused by colds could help in the search for a successful vaccine.
He added: “This is exciting, as understanding the basis for this activity could lead to vaccines that work against a range of coronaviruses, including the common cold strains, as well as SARS-CoV-2 and any future pandemic strains.
“But it is important to stress that there are still many unknowns which require further research. For example, exactly how is immunity to one coronavirus modified by exposure to another? Or why does this activity decline with age?
“It is not the case that people who have recently had a cold should think they are immune to Covid-19.”
A large study is now under way, in partnership with researchers at Imperial College London and University College London, to uncover the role different antibodies and other immune defences play in protection against coronavirus.