Companies scramble to expand coronavirus vaccine supply

WASHINGTON - Production of the two coronavirus vaccines authorized in the United States is accelerating while companies with experimental vaccines nearing the end of trials struggle to meet ambitious manufacturing targets.

That means the United States should have 200 million doses each from the companies with authorized shots, Pfizer-BioNTech and Moderna - enough to guarantee that more than 70% of adults will be able to get the two-shot vaccination by the end of July. That is comparable to the share of adults some polls suggest will be willing to roll up their sleeves...