Booster shot offers nine-fold increase in COVID-19 antibodies: Johnson & Johnson

"New interim data from these studies demonstrate that a booster dose of the Johnson & Johnson COVID-19 vaccine generated a rapid and robust increase in spike-binding antibodies, nine-fold higher than 28 days after the primary single-dose vaccination," the company said in a statement.

The company conducted a two-phase study in individuals in the US and Europe who were vaccinated with its single-shot vaccine months earlier, it added. The full study is yet to be released.

“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,” Global Head of R&D, Mathai Mammen, said.

The company plans to discuss with public health officials its potential strategy for COVID-19 vaccine, boosting eight months or longer after the primary single-dose vaccination, he added.

The announcement comes days after the US Centers for Disease Control and Prevention said it would greenlight booster shots for Pfizer and Moderna COVID-19 vaccines in September as studies have shown decreased efficacy against the Delta variant.