NEW YORK - Johnson & Johnson announced that its one-dose vaccine provided strong protection against Covid-19. It was less effective against a new variant.
The Johnson & Johnson results came with a significant cautionary note: The vaccine’s efficacy rate dropped from 72 percent in the United States to 57 percent in South Africa, where a highly contagious variant is driving most cases.
Studies suggest that this variant also blunts the effectiveness of Covid-19 vaccines made by Pfizer-BioNTech, Moderna and Novavax. The variant has spread to at least 31 countries, including the United States, where two cases were documented this week.
Johnson & Johnson said that it planned to apply for emergency authorization of the vaccine from the Food and Drug Administration as soon as next week, putting it on track to receive clearance later in February.
“This is the pandemic vaccine that can make a difference with a single dose,” said Dr. Paul Stoffels, the chief scientific officer of Johnson & Johnson.
The company’s announcement comes as the Biden administration is pushing to immunize Americans faster even with a tight vaccine supply. White House officials have been counting on Johnson & Johnson’s vaccine to ease the shortfall. But the company may only have about seven million doses ready when the F.D.A. decides whether to authorize it, according to federal health officials familiar with its production, and about 30 million doses by early April.
