In the Homeless Rehab COVID demo we consider the challenges of Sarah Thomson, who as a result of an auto accident while under the influence of opioids has lost her license, her car is totaled, she lost her job delivering groceries, was evicted from her apartment, and her two children have been put in foster care with her mother. The court refers her to a homeless rehabilitation program to enable her to start rebuilding her life. A requirement of entering the facility is she must take a COVID survey, which stores a condition in her patient record that she is suspected of having COVID. But she has elected to exercise her 42 CFR part 2 rights to not have her substance use disorder shared with anyone. So, there is no way for the rehab center to retrieve the status of her COVID survey without revealing that Sarah has a substance use disorder. This COVID alerting demo involves a COVID survey app, an Electronic Health Records System (EHR), a Community Infectious Disease Alerts Service (CIDAS), a Homeless Management Information System, and a Rehab Shelter Management app. The COVID app uses the FHIR Questionnaire/QuestionnaireResponse Resources standard to create a clinical record Condition of Suspected COVID in Sarah’s medical record in the EHR. The CIDAS uses the FHIR Subscription API to learn of Sarah’s infectious disease condition from the EHR. The HMIS uses a FHIR Subscription API to subscribe to COVID alerts from the CIDAS on behalf of the Rehab Shelter Management app.