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(WJW) — Johnson & Johnson announced Wednesday that using its COVID-19 vaccine as a booster shot increased antibodies nine-fold higher than 28 days after the first shot.

That’s according to clinical trial studies in people previously vaccinated with the single-shot vaccine, the company said in a press release.

According to Johnson & Johnson, the booster dose of the vaccine “generated a rapid and robust increase in spike-binding antibodies” in participants between the ages of 18 and 55 and in those 65 years and older.

“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. 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,” said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, Johnson & Johnson. “We look forward to discussing with public health officials a potential strategy for our Johnson & Johnson COVID-19 vaccine, boosting eight months or longer after the primary single-dose vaccination.”

Johnson & Johnson said it is working with the FDA, CDC and other health authorities regarding booster shots, and ongoing trials are underway.