Last month, the government authorized a second COVID-19 booster shot for anyone 50 and older whose last shot was more than four months ago. But just because an extra shot is permitted doesn't mean everyone should get one, health experts say – at least not yet. For those with a healthy immune system, the first two doses dramatically reduce the risk of death from COVID-19. Studies show a third shot likely takes severe disease off the table, too, even with omicron, which swept across the world and infected roughly half of all Americans. But scientific research doesn't offer much guidance on a fourth shot, and the decision has to be highly personal, experts said. Click the link in our bio to read what some experts have told USA TODAY about the a second booster shot.