The U.S. vaccine supply for next month just got bigger.
On Tuesday, Johnson & Johnson said it will be ready next month to ship 20 million doses of its one-shot vaccine. That adds to a coming surge in vaccine availability, according to a Bloomberg analysis of drugmaker promises.
Along with vaccines from Pfizer Inc. and Moderna Inc., which both require two doses, the delivery targets through next month will be enough to fully vaccinate 130 million Americans.
Bloomberg’s analysis is based on company statements, data on the number of shots already delivered and conversations with people familiar with the efforts who spoke on...