As hundreds, even thousands, of Maryland residents are diagnosed each day with Covid-19, health workers around the state try to interview them and offer help, ask who they’ve spent stretches of time with recently, and contact those people to warn they may have been exposed. Contact tracing can be a powerful tool to control spread of the virus, but the system is stretched. We hear about it from Dr. Nilesh Kalyanaraman, Anne Arundel County’s health officer and Nurse Kristy Frashure describes the tracing calls. Plus, Stephen Babcock of Techical.ly Baltimore tells us how the MD Covid Alert phone app works.