Featuring articles on early transmission dynamics of Covid-19, PCI in patients at high bleeding risk, luspatercept in patients with β-thalassemia, fostemsavir in multidrug-resistant HIV-1 infection, activating immunity to fight a foe, and from Ariadne’s thread to the labyrinth itself; a review article on endometriosis; a case report of a man with pancytopenia and acute renal failure; and Perspective articles on stalled federal efforts to end surprise billing, on misguided changes to SNAP, on defining the epidemiology of Covid-19, and on suicide.