https://www.scientificamerican.com/article/new-johnson-johnson-shot-prevents-severe-covid-as-well-as-existing-vaccines-do-experts-say/ > When getting vaccinated against covid-19, there’s no sense being picky. You should take the first authorized vaccine that’s offered, experts say. > The newest covid vaccine on the horizon, from Johnson & Johnson, is probably a little less effective at preventing sickness than the two shots already being administered around the U.S., from Pfizer-BioNTech and Moderna. On Saturday, the Food and Drug Administration authorized the Johnson & Johnson vaccine after reporting it showed about 66% effectiveness at preventing covid illness in a 45,000-person trial. No one who received the vaccine was hospitalized with or died of the disease, according to the data released by the company and FDA. As many as 4 million doses could be shipped out of J&J’s warehouses beginning this week.