• Analysis: Why it matters that the Trump White House lied about his Covid case
원문출처 : https://www.cnn.com/2021/12/07/health/omicron-variant-pfizer-vaccine-south-africa-study/index.html
원문출처 : https://www.cnn.com/2021/12/07/health/omicron-variant-pfizer-vaccine-south-africa-study/index.html