Public-health officials and vaccine experts hope more than one vaccine will cross the finish line, to boost the total number of doses available.

“Ideally we’d want seven or eight billion doses the day after licensure, so we can vaccinate the whole world,” said Walter Orenstein, associate director of Emory University’s vaccine center in Atlanta. “The likelihood is we won’t have enough to vaccinate even the entire U.S. population” when a vaccine first becomes available, he said.

The prospect of limited initial supplies has triggered maneuvering over which countries get first dibs. Companies receiving U.S. federal grants, including J&J, Moderna and Sanofi, are expected to reserve some doses for Americans, according to industry officials…

Groups likely to be at the head of the line for access are front-line health-care workers and first responders, plus essential workers like grocery, pharmacy, food-supply and mass-transit employees, said Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, who serves on a committee with federal and drug-industry officials that is trying to accelerate coronavirus vaccine development.