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Study of COVID-19 in Retirement Communities


  • Retirement communities have a greater risk for COVID-19 transmission and severe cases.
  • Abt will monitor asymptomatic and symptomatic older adults.
  • Results are ongoing.
The Challenge

Older adults are among those with the highest risk for medically attended COVID-19. CDC needs characterization of risk factors and clinical epidemiology of COVID-19 among older adults. The information will inform public health strategies to prevent infection and reduce the burden of severe disease in this population.

The Approach

The CITRUS project will enroll retirement community residents from independent living homes and assisted living facilities over a 12-month period. Active surveillance will capture symptomatic and asymptomatic COVID-19 cases among participants. The primary objectives of the study are to: 1) estimate the cumulative incidence of asymptomatic and symptomatic infection in community-dwelling older adults; and 2) establish kinetics of immunity over time. Secondary objectives include describing illness severity, infection risk factors, healthcare utilization, and immune response to and effectiveness of vaccination.

The Results

The CITRUS project is currently enrolling participants in Florida and Arizona.