Study: US COVID infections may have been twice the number reportedRoughly 15.9 million asymptomatic US COVID-19 cases may have gone undetected as of Sep 30, 2020, which would double the cases reported to the Centers for Disease Control and Prevention (CDC) during that time, according to a research letter detailing a 6.6% nationwide SARS-CoV-2 seroprevalence rate.The letter, written by Clinical Reference Laboratory scientists in Kansas and published today in JAMA Network Open, describes a national convenience sample of 61,910 generally healthy adult life insurance applicants evaluated for the presence of SARS-CoV-2 antibodies in September.Of the 61,910 participants, 4,094 (6.6%) had coronavirus antibodies, or were seropositive, indicating