Should Johnson & Johnson’s (J&J) COVID-19 vaccine be a two-dose series? While not directly asked, that question almost lurks between the lines of the FDA’s briefing document for the Oct. 15 meeting of its Vaccines and Related Biological Products Advisory Committee. The document referred to J&J’s proposed second dose as a “booster,” but the FDA isn’t asking the committee the questions it posed for the Moderna Inc. and Pfizer Inc.-Biontech SE boosters. Instead, it is inviting VRBPAC to advise on whether the second J&J dose should be administered two months or six months following the first shot.