Vaccine makers are preparing for a next possible phase of the Covid-19 vaccine rollout: booster doses.
원문출처 : https://www.cnn.com/2021/06/23/health/covid-19-vaccine-boosters-questions-update-wellness/index.html
원문출처 : https://www.cnn.com/2021/06/23/health/covid-19-vaccine-boosters-questions-update-wellness/index.html