The first one-shot COVID-19 vaccine provides good protection against the illness, Johnson & Johnson reported in a key study released Friday, offering the world a potentially important new tool as it races to stay ahead of the rapidly mutating virus. The pharmaceutical giant’s preliminary findings suggest the single-dose option may not be as strong as Pfizer’s or Moderna’s two-dose formula, and was markedly weaker against a worrisome mutated version of the virus in South Africa. But amid a rocky start to vaccinations worldwide, that may be an acceptable trade-off to get more people inoculated faster with an easier-to-handle shot that, unlike rival vaccines that must be kept frozen, can last months in the refrigerator. “Frankly, simple is beautiful,” said Dr. Matt Hepburn, the U.S. government’s COVID-19 vaccine response leader. J&J plans to seek emergency use authorization in the U.S. within a week. It expects to supply 100 million doses […]