By February 2022, after the wave of the omicron version of the coronavirus had swept through the United States, about three-quarters of the children under the age of 18 had already developed antibodies to the vaccine, indicating they had been exposed to the virus, NBC News reports.
Because the vast majority of that population was not yet eligible for one of the vaccines available, the acquisition of antibodies came through natural infection for most of them.
Children under 18 typically had slight or no symptoms themselves if they became infected with the virus, but they could infect others with the virus during the virus’s early days. While the infections rarely led to hospitalizations, studies now show even a mild infection can have long term impacts for children.