United States. Department of Health and Human Services. "Joint Statement from HHS Public Health and Medical Experts on COVID-19 Booster Shots, August 18, 2021" in United States. Department of Health and Human Services : Press Releases Relating to the COVID-19 Pandemic (August 18, 2021). https://fraser.stlouisfed.org/title/6354/item/607495, accessed on December 11, 2024.