NEW BRUNSWICK, N.J. - Johnson & Johnson said Wednesday that new data support a booster dose of its COVID-19 vaccine after studies showed antibodies levels were nine times higher than after the original dose of its vaccine.The company said in a release that interim data showed that a booster dose "generated a rapid and robust increase in spike-binding antibodies, nine-fold higher than 28 days after the primary single-dose vaccination." A prior study published in July also found that people vaccinated with the Johnson & Johnson vaccine still had "strong and stable" antibody responses eight months later."We have established that a single shot of our COVID-19 vaccine generates strong and robust immune responses that are durable and persistent.