• Exclusive: South Africa at breaking point with Delta variant
원문출처 : https://www.cnn.com/2021/07/09/health/pfizer-third-coronavirus-vaccine-dose-explainer-wellness/index.html
원문출처 : https://www.cnn.com/2021/07/09/health/pfizer-third-coronavirus-vaccine-dose-explainer-wellness/index.html