PROJECT SUMMARY/ABSTRACT This revision to Years 29-34 of the Health and Retirement Study (HRS) cooperative agreement seeks to collect and analyze saliva samples from up to 17,639 HRS participants for the presence of antibodies to SARS-CoV-2. The effect of the virus on cognitive function and the development of Alzheimer’s Disease and Alzheimer’s Related Dementias (AD/ADRD) is a major concern for the future public health of the older population. While severe cases of COVID-19 requiring hospitalization will be well-documented for future study, many less severe cases go completely undiagnosed, making it difficult to accurately study outcomes of all types of exposure. To be useful, antibody testing must be done before vaccines are available, which means the risk of infection from the collection of samples in person is a serious concern. We therefore propose to use a self-administered saliva test, with innovative shipping technology to maintain samples at 4 degrees Celsius during return shipping to the analytic lab. The University of Minnesota’s Advanced Research Diagnostics Lab, a CLIA-certified facility and one of 4 national reference laboratories selected by the National Cancer Institute for SARS-CoV-2 antibody testing, will conduct the assays. Participants will receive a report of positive or negative antibody status, while more detailed continuous measures of antibody titers will be available for research from the positive cases. Data will be made available to the research community for use with the wealth of HRS data on genetics, immune function, and social interactions.