Looks like the johnson and johnson one shot vaccine only offers "66% protection".
Moderna’s and Pfizer’s two-dose vaccines are 94% and 95% effective, respectively, at preventing new coronavirus infections, according to the Centers for Disease Control. And while it’s more convenient, the single shot Johnson & Johnson vaccine only provides 66% protection.
Brooklyn woman gets COVID 3 weeks after Johnson & Johnson vaccine
https://nypost.com/2021/04/10/brooklyn-woman-gets-covid-3-weeks-after-johnson-johnson-vaccine/amp/