Johnson & Johnson is reporting those receiving a booster shot after 6 months show a 9 times increase in antibody levels. The data isn’t peer reviewed yet so it’s early days I guess.

J&J said researchers found antibody levels increased ninefold among people who received a second dose of its vaccine, compared with one month after they received a first dose. The company didn’t specify exactly when or how many subjects received the second dose, though information posted about the clinical trial in an online government database indicates it was administered six months after the first shot.

J&J said that it will submit data from two studies to a preprint server, meaning that the data haven’t been peer-reviewed or published in a scientific journal.

Wall Street Journal