The company’s Phase 1/2a study showed that a booster dose given six months after the first vaccination increased a person’s antibody levels by nine-fold a week after the booster. The antibody levels continued to increase to 12-fold four weeks after the booster.

Johnson & Jonhson said its COVID-19 vaccine when given as a primary or booster dose is “well-tolerated” by those who received it based on the data from the ENSEMBLE 2 trial. The company added that no new safety signal was observed.

“Today’s recommendation by the VRBPAC is another step toward ensuring that those who have received the single-shot Johnson & Johnson vaccine – or will receive it in the future – are provided the opportunity to increase their protection against COVID-19,” said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, Johnson & Johnson.

In the United States, 15.1 million people received the Johnson & Johnson COVID-19 vaccine as a primary vaccination. The company said it has a sufficient supply of booster shots for them.