US regulators on Saturday authorized a third COVID-19 vaccine, a single-dose shot by Johnson & Johnson that could help speed vaccinations. The move by the Food and Drug Administration came after an expert panel debated the evidence to allow widespread use of J&J's vaccine. Dr. Francis Collins, the director att the National Institutes of Health says having a third vaccine option is really good news. "We had two emergency use authorize vaccines and now we have three. And the third one is a single dose from J and J, which makes it a little easier to organize. But I think the bottom line would be whatever vaccine you get offered, take it. They are all really good. And the most important thing we can do right now is to get as many shots in as many arms as we can," he said. U.S. officials expect to have only a few million doses to divide between states in initial shipments. J&J has said it can supply enough to vaccinate 20 million people by the end of March. So far, more than 46 million Americans have received at least one dose of vaccine made by Pfizer or Moderna, and about 22 million of them have received the second dose required for full protection. Two doses of the Pfizer and Moderna shots were found to be about 95% effective against symptomatic COVID-19. The numbers from J&J's study are not that high, but it's not an apples-to-apples comparison. One dose of the J&J vaccine was 85% protective against the most severe COVID-19. After adding in moderate cases, the total effectiveness dropped to about 66%. "But what people I think are mostly interested in is, is it going to keep me from getting really sick? Will this vaccine keep me out of the hospital, out of the ICU? And worse yet, will it keep me from dying from this terrible disease? The good news is all of these say yes to that," said Collins. The J&J shot was tested in the U.S., Latin America and South Africa at a time when more contagious mutated versions of the virus were spreading. Health experts have recommended that eligible people get whatever COVID-19 shot is available. "We are going to get through this by moving the vaccines forward as fast as we can and getting everybody in our country and eventually the world immunized against Covid-19," said Collins.