NEW YORK — Johnson & Johnson announced on Tuesday it had submitted data to the U.S. Food and Drug Administration for emergency use authorization of a booster shot of its Covid-19 vaccine in people ages 18 years and older.

While scientists are divided over the need for booster shots when so many people in the United States and other countries remain unvaccinated, the Biden administration announced the push for an extra dose in August as part of an effort to shore up protection against the highly transmissible delta variant.

Over 15 million Americans have received Johnson & Johnson’s vaccine, which is administered as a single dose, according to the latest data from the Centers for Disease Control and Prevention.

“A booster of our COVID-19 vaccine increases levels of protection for those who have received our single-shot vaccine to 94 percent,” said Mathai Mammen, global head of research and development at J&J’s Janssen subsidiary. “At the same time, we continue to recognize that a single-shot COVID-19 vaccine that provides strong and long-lasting protection remains a crucial component to vaccinating the global population.”

The Food and Drug Administration’s independent vaccine advisory committee is scheduled to meet on Oct. 14 to consider the J&J booster shot, clearing the way for the agency to make a final decision about whether to authorize its use.