In Covid, oxygen levels in the body can crash without noticeable symptoms - it’s known as “silent hypoxia”. This week we’ll be discussing whether letting people monitor their oxygen levels at home with a pulse oximeter could save lives. James talks to Chris Harris, who’s been using one, and two pioneers of the project - Dr Matt Inada-Kim, Consultant in Acute Medicine at Hampshire Hospitals NHS Trust, and Dr Caroline O'Keeffe who runs oximetry@home in North Hampshire. And the hotly debated topic of rapid, or lateral flow, testing. Local councils are rolling them out for people who can't work from home, and the hope is that they could help us keep on top of the virus by picking out people with Covid. Could it be a way out of the pandemic or could it cause more harm than good? Prof Irene Petersen and our own Dr Margaret McCartney are on the case. Dr Navjoyt Ladher answers some of the most common questions about vaccines. PRESENTER: James Gallagher PRODUCER: Beth Eastwood