How kids’ immune systems can evade COVID – Nature

Young children account for only a small percentage of COVID-19 infections — a trend that has puzzled scientists. Now, a growing body of evidence suggests why: kids’ immune systems seem better equipped to eliminate SARS-CoV-2 than are adults’.

“Children are very much adapted to respond — and very well equipped to respond — to new viruses,” says Donna Farber, an immunologist at Columbia University in New York City. Even when they are infected with SARS-CoV-2, children are most likely to experience mild or asymptomatic illness.

Another clue that children’s response to the virus differs from that of adults is that some children develop COVID-19 symptoms and antibodies specific to SARS-CoV-2 but never test positive for the virus on a standard RT-PCR test. In one study, three children under ten from the same family developed SARS-CoV-2 antibodies — and two of them even experienced mild symptoms — but none tested positive on RT-PCR, despite being tested 11 times over 28 days while in close contact with their parents, who had tested positive.