Research and manufacturing delays have dogged the arrival of a COVID-19 vaccine from Novavax Inc., one of only six selected by the U.S. government's Operation Warp Speed for a large order. At one point in May, the company’s shares were down 62% from a February high.

On Monday, though, Novavax took a step toward a comeback, announcing that its vaccine was 90.4% effective in preventing mild and moderate COVID-19 in a large trial in the U.S. and Mexico and prevented all severe disease.

Late or not, the promising data suggests that Novavax's effort could be crucial in a pandemic fight that won't end soon. Even for those jaded by dozens of data releases, this is an impressive result that should help pave the way for rapid approval and rollout in the third quarter. The vaccine won’t see much initial use in the U.S., where the vaccination rate is already high, but it will be instrumental in inoculating the world, which is vital in the effort to tame the virus, keep variants at bay and minimize the human and economic damage.