A booster shot of the Johnson & Johnson coronavirus vaccine offers a significant increase in antibodies, the company announced on Wednesday.

Driving the news: People who received a booster shot six to eight months after their first J&J dose saw "a rapid and robust increase in spike-binding antibodies, nine-fold higher than 28 days after the primary single-dose vaccination," J&J said.

• The data comes from two Phase 2 studies in individuals previously vaccinated with the single-shot vaccine.
• "We have established that a single shot of our COVID-19 vaccine generates strong and robust immune responses that are durable and persistent through eight months," Mathai Mammen, global head of research and development for Janssen, said in a statement.
• "With these new data, we also see that a booster dose of the Johnson & Johnson COVID-19 vaccine further increases antibody responses among study participants who had previously received our vaccine."

The big picture: The announcement comes a week after the federal government announced that beginning the week of Sept. 20, those who received a Pfizer or Moderna vaccine should expect to be offered a booster shot eight months after their second dose.

• The J&J vaccine was not part of the Biden administration's initial booster plan due to lack of data, per the New York Times.
• Johnson & Johnson says it will submit the data to Food and Drug Administration, and it looks "forward to discussing with public health officials a potential strategy for our Johnson & Johnson COVID-19 vaccine."

Go deeper: What to know if you got the J&J vaccine