A vaccine jointly developed by Pfizer and BioNTech was 90 percent effective in preventing Covid-19 infections in ongoing Phase 3 trials, the companies announced Monday.
Protection in patients was achieved seven days after the second of two doses, and 28 days after the first, according to preliminary findings.
"The first set of results from our Phase 3 Covid-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent Covid-19," Pfizer chairman and CEO Albert Bourla said in a statement.
"We are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis.
"We are reaching this critical milestone in our vaccine development program at a time when the world needs it most," Bourla added.
Across much of the globe, Covid-19 infections rates are soaring to record highs, with hospital intensive care units filling up and death tolls mounting as well.
Based on supply projections, the companies said they expect to supply up to 50 million vaccine doses globally in 2020, and up to 1.3 billion doses in 2021.