Pfizer appointments were all but gone by Monday morning, and many people were frustrated. So even those who managed to snag a Pfizer-specific second-dose appointment are not guaranteed they will get that vaccine. Instead, the appointments will simply be designated as mRNA vaccine clinics, which means you could get Pfizer or Moderna injected into your arm — the mix-and-match system. For example, only the Pfizer vaccine is approved for people age 12 to 18, so enough doses must be set aside at all clinics. —@PippyGolfProHaggie said the change is to ensure that people ultimately get a vaccine when they have an appointment.

Source: CBC News June 22, 2021 21:45 UTC