Officials are expected to present three sets of data at Wednesday's White House Covid-19 briefing that suggest waning vaccine protection against Covid-19 infection in the United States, a senior federal health official tells CNN.
원문출처 : https://www.cnn.com/2021/08/18/health/white-house-covid-boosters/index.html
원문출처 : https://www.cnn.com/2021/08/18/health/white-house-covid-boosters/index.html