The Johnson & Johnson coronavirus vaccine prevented 100% of hospitalizations and deaths in clinical trials, the company said today.

Why it matters: The single-dose vaccine could speed up the vaccinations of America’s vulnerable populations, as new variants spread.

By the numbers:

• Overall: 66% effective in preventing moderate to severe COVID in nearly 44,000 participants in Phase 3 trials across eight countries.
• In the U.S.: 72% effective.
• In South Africa, home of a more aggressive variant: 57% effective.

What they’re saying:

• Former CDC director Tom Frieden on the Axios Re:Cap podcast: “It has a lot of advantages, easier to store, easier to make.”
• Former FDA commissioner Scott Gottlieb: “The J&J vaccine turns in a fantastic result. We now have three highly effective vaccines. This vaccine showed sustained (and increasing!) immune protection over time, perhaps from a robust early induction of memory immune cells (CD4 and CD8).”

What’s next: J&J is expected to apply for an emergency use authorization next week, the N.Y. Times reports.

• “Federal regulators are also still waiting on data from Johnson & Johnson’s new manufacturing facility in Baltimore that prove it can mass-produce the vaccine. The company is counting on that factory to help reach its contractual pledge to the federal government of 100 million doses by the end of June.”