Ages are recommended
5+ years old
At 3 week (21 day) intervals 
2 weeks after the final dose in the primary series
Everyone aged 12+ should receive a booster dose at least 5 months after the last dose in their primary series.
- Teenagers 12-17 should only receive a Pfizer-BioNTech COVID-19 Vaccine booster
- All 18+ should receive a booster dose of either Pfizer-BioNTech or Moderna (mRNA COVID-19 vaccines)
A person is considered “boosted” and up to date just after receiving their booster dose.