By\u00a0Erin Garcia de Jes\u00fas<\/a> June 11, 2021 @ SicenceNews<\/p>\n\n\n\n Roughly six months ago, on December 11, the Food and Drug Administration authorized the first COVID-19 vaccine for emergency use in the United States. What followed was a push to get that shot, developed by Pfizer and BioNTech, to those at high risk<\/a> (SN: 12\/1\/20<\/em>). Moderna\u2019s jab wasn\u2019t far behind<\/a>, securing emergency use authorization just a week after Pfizer\u2019s<\/a> (SN: 12\/17\/20; SN: 12\/11\/20<\/em>). And then in February 2021, there were three COVID-19 vaccines when the FDA authorized Johnson & Johnson\u2019s shot<\/a> (SN: 2\/27\/21<\/em>). <\/p>\n\n\n\n Now, around 40 percent of the U.S. population is fully vaccinated. Just over half of residents have gotten at least one dose. Meanwhile, U.S. cases of COVID-19 and deaths have plunged to their lowest levels since March 2020. <\/p>\n\n\n\n Amid the ongoing effort to vaccinate people, two big questions loom: Will immune protection against the coronavirus be long-lived? Or will people soon need booster shots?<\/p>\n\n\n\n