As the world learns more about the Omicron coronavirus variant and Delta continues to cause Covid-19 cases to rise around much of the United States, the need for booster shots becomes clearer than ever -- even beyond the growing data about waning vaccine immunity.
원문출처 : https://www.cnn.com/2021/12/08/health/pfizer-booster-data-omicron-vaccinated-definition/index.html
원문출처 : https://www.cnn.com/2021/12/08/health/pfizer-booster-data-omicron-vaccinated-definition/index.html