Most Americans have been infected with the coronavirus at least once, the C.D.C. says.

Blood tests showed a sharp increase in the proportion of people — especially children and adolescents — in the United States who had antibodies indicating past exposure to the virus, the agency said.Blood tests showed a sharp increase in the proportion of people — especially children and adolescents — in the United States who had antibodies indicating past exposure to the virus, the agency said.Coronavirus (2019-nCoV), United States, Centers for Disease Control and Prevention, Disease RatesRead More