Next Hurdles For COVID-19 Vaccine Development: Selecting Endpoints, Getting Enough Subjects

US FDA's Peter Marks and industry execs discuss challenges in moving candidate vaccines to Phase II/III trials, including international regulatory alignment on clinical endpoints and other issues. J&J's Paul Stoffels says it is going to be a 'Herculean task' to conduct placebo-controlled studies in 30,000 to 100,000 people.