Everyone age 16+ in Massachusetts is now eligible under Phase 3, which started on April 19, 2021. Some vaccination clinics may have more specific eligibility requirements, so be sure to check when signing up. Note that minors (16-17 years old) are only eligible to receive the Pfizer vaccine, not Moderna or Janssen. Most sites require appointments. Clinics that are open to walk-ins will be listed as such.