In the U.S., emergency-use authorization has been granted for convalescent plasma, the efficacy of which is yet to be robustly tested. For some, this echoes the situation with hydroxychloroquine and the government’s subsequent U-turn on its rollout.Meanwhile, America’s infection rate appears to be flattening out — but at tens of thousands of cases per day. This stands in stark contrast to China, where daily cases are under 40.Overseas, a Hong Kong resident has been reinfected with the virus, the first recorded instance of a second bout. And Russia and China have begun distributing vaccines, sidestepping Phase 3 safety trials to the incredulity of immunologists and vaccine executives.We check back in with Donald G. McNeil Jr. on the coronavirus and the impact of these developments.Guest: Donald G. McNeil Jr., a science and health reporter for The New York Times For more information on today’s episode, visit nytimes.com/thedaily Background reading: A 33-year-old man in Hong Kong was infected with the coronavirus for a second time. It is unclear how often people might become reinfected, and how soon after the first bout.Despite flattening, America’s infection rate remains one of the highest in the world.The F.D.A. has permitted the expansion of convalescent plasma treatment after pressure from President Trump.Russia has approved a coronavirus vaccine and is set to begin mass vaccinations in the fall. China has reportedly been giving experimental vaccines to high-risk groups since July.