Johnson & Johnson says it has evidence that people who received its one-shot COVID-19 vaccine could benefit from a booster shot after six months.

The pharmaceutical giant said in a news releaseWednesday that when it gave participants in a study a second jab of its coronavirus vaccine after six months, their antibody levels were nine times higher than 28 days after their first dose.

The data suggest an additional shot might serve as a booster if the vaccine's effectiveness begins to wane.

"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," said Mathai Mammen, global head of Janssen Research & Development, Johnson & Johnson, 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," he added.

The data have not yet been published in a scientific journal or reviewed by other researchers.

Johnson & Johnson says it is planning to submit the results of the study to the Food and Drug Administration to help make a case for authorizing a booster for everyone who received the company's vaccine.

The Biden administration has already announced plans to begin rolling out boosters in September for people who received the Moderna and Pfizer vaccines.

U.S. Surgeon General Vivek Murthy previously said health officials were concerned about "waning immunity and the strength of the delta variant," the highly contagious strain driving a surge of new infections.

The World Health Organization has called on countries to delay their plans for booster shots until nations with lower vaccination rates can immunize more of their population.

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