Nation Pfizer, J&J report strong antibody response from booster shots; heart swelling more likely from COVID than vaccine: Latest COVID-19 updates August 25, 2021August 25, 2021Christal Hayes, Jeanine Santucci and Ryan W. Miller, USA TODAYComments Off on Pfizer, J&J report strong antibody response from booster shots; heart swelling more likely from COVID than vaccine: Latest COVID-19 updates Johnson & Johnson said studies show a booster dose of its vaccine offered a ninefold increase in antibodies. The latest COVID-19 updates.