Last updated: November 22, 2021. CDC Guidance on COVID-19 Booster Shots. The Centers for Disease Control and Prevention (CDC) has released recommendations about who should and who may receive booster shots for the Pfizer-BioNTech, Moderna, and Johnson & Johnson COVID-19 vaccines.. A booster shot is given at least six months after the second dose of the Pfizer or Moderna vaccine, or two months ....