https://www.siliconvalley.com/2021/09/21/two-dose-version-of-johnson-johnson-vaccine-94-effective-against-covid-19-study-finds/ > A two-dose version of Johnson & Johnson’s coronavirus vaccine provides 94% protection against symptomatic infection, the company said Tuesday — making a two-dose regimen of J&J’s Janssen vaccine comparable to a two-dose regimen of Moderna’s or Pfizer’s. > Plus, the company said, adding a booster dose to a single shot of the vaccine raised immunity even more, and should also protect people strongly against infection.