The Study of Women's Health Across the Nation (SWAN): The Impact of Midlife and the Menopause Transition on Health and Functioning in Early Old Age. Administrative Supplement ABSTRACT The Coronavirus Disease 2019 (COVID-19) pandemic, has dramatically changed the way we live and interact. In addition to claiming more than 220,000 lives and infecting more than 8 million people in the United States (US) to date, many more millions have suffered economically through job or business loss; suffered from social isolation, anxiety or depression; and have not received or delayed medical care. This administrative supplement to SWAN-Aging: The Impact of Midlife and the Menopause Transition on Health and Functioning in Early Old Age (1U19AG063720-01A1) is in response to the Notice of Special Interest NOT-AG-20-022: NIA Availability of Administrative Supplements and Revision Supplements on COVID-19. The pandemic is especially pertinent to SWAN-Aging participants as they are a high-risk, and potentially high-exposure, population given their age and residential locations. The Study of Women’s Health Across the Nation (SWAN) is a multi-racial/ethnic cohort of women, enrolled at age 42-52 and followed for over 25 years with longitudinal measures of economic strain and stress, health behaviors, cognitive and physical functioning, and mental and physical health. SWAN-Aging will prospectively link comprehensive longitudinal characterization of the menopause transition (MT) and midlife health indicators to functioning and multiple health domains in early old age (65-75 years), including cognitive impairment and cognitive decline, physical functioning, psychological well-being, sleep, and cardiovascular and bone health. A follow-up visit, planned to start July 2021, provides a unique opportunity to evaluate the longer-term impact of the pandemic on women’s economic security, access to health care, their cognitive and physical functioning, and physical and mental health in early old age. SWAN- Aging’s overall goal is to enhance understanding of successful aging in women. Without collecting time- sensitive data on COVID-19 infection and its consequences, SWAN-Aging will not be able to account for the impact of the pandemic on participants’ health and well-being. This administrative supplement is designed to evaluate the effect of infection and symptoms, social and economic disruption, and delayed medical care on multiple aspects of health and functioning in early old age. The wealth of previously collected longitudinal data will allow us to a) account for person-specific, pre-pandemic trajectories of biology, functioning, and health, when disentangling the causal impact of the COVID-19 pandemic from aging, and b) delineate risk and protective factors for pandemic-related effects on health and functioning. Its goals are 1) to characterize COVID-19 infection (seropositivity, symptoms, and hospitalizations) and determine longer-term effects of the pandemic on health and fu...