Pfizer said Thursday it is seeing waning immunity from its coronavirus vaccine and says it is picking up its efforts to develop a booster dose that will protect people from variants.
원문출처 : https://www.cnn.com/2021/07/08/health/pfizer-waning-immunity-bn/index.html
원문출처 : https://www.cnn.com/2021/07/08/health/pfizer-waning-immunity-bn/index.html