Business News Covid-19: Johnson & Johnson’s vaccine 66% effective in large global trial In the trial of nearly 44,000 volunteers, the level of protection against moderate and severe COVID-19 varied from 72 per cent in the United States Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Emirates, Etihad work out travel options for passengers as UK suspends flights Covid-19: J&J’s single-dose vaccine 66% effective