SciCheck Digest The mRNA COVID-19 vaccines teach the immune system to recognize and fight the coronavirus, greatly reducing the likelihood of severe disease if a person is infected. There is no evidence the vaccines impair immunity, as some, including Fox News' Tucker Carlson, have baselessly claimed. How safe are the vaccines? More than half a billion doses of COVID-19 vaccines have now been administered in the U.S. and only a few, very rare, safety concerns have emerged. The vast majority of people experience only minor, temporary side effects such as pain at the injection site, fatigue, headache, or muscle pain — or no side effects at all. As the Centers for Disease Control and Prevention has said...