The U.S. EPA needs adults ages 18 and older to participate in a research study. The purpose of this research study is to develop a non-invasive assay for population surveillance of COVID-19, the illness caused by the new SARS-CoV-2 coronavirus. The study involves measuring antibodies in saliva samples collected from adults 18 and up. These antibodies are naturally produced by the human body in response to SARS-CoV-2 infection. You will provide saliva samples by mail and complete a short questionnaire. Compensation up to $100. For more information, please visit our website at www.epastudies.org or call MPF Federal EPA Recruiting at 1-888-279-9353.