As waves of new coronavirus variants circulate the globe, one thing has become clear: human immunity against the virus fades over time.
원문출처 : https://www.cnn.com/2022/05/20/health/mrna-vaccine-technology-covid-19-durability/index.html
원문출처 : https://www.cnn.com/2022/05/20/health/mrna-vaccine-technology-covid-19-durability/index.html