Fully Covid-19 vaccinated people are relatively safe from severe illness and death from COVID-19. Even highly efficient vaccines, however, might lose their effectiveness with time. A “booster shot,” which is an additional dose of the vaccination given several months after the last dose, can help improve the vaccine’s effectiveness.

However, different vaccines may require boosters at other times. According to CDC data, the Pfizer vaccine is still 91 percent effective after four months but reduced to 77 percent. On the other hand, the Moderna vaccine looks to be 92 percent effective almost five months after vaccination. 

The CDC recommends booster shots for fully vaccinated people. The time is determined by the vaccine you receive first.

  • Pfizer-BioNTech: After the two shots required for the primary series of the Covid-19 vaccine, people 12 or older are eligible for a booster shot five months after the last dose. People 12-17 years old may only get a Pfizer booster. Everyone else can get booster shots from either Pfizer or Moderna.
  • Moderna: After the first series, anyone 18 or older can get a booster shot five months after the last dose.
  • Johnson & Johnson’s Janssen: People 18 and over are eligible for a booster shot, preferably from Pfizer or Moderna, two months after the first dose.


Additional Boosters

Some people may need an extra booster dose to boost their immune system against COVID-19 variations. You’re eligible for a second Covid-19 booster shot four months after your first booster if you have a weakened immune system or are 50 or older. The CDC advises a second booster using an mRNA COVID-19 vaccine if you had the J&J Janssen vaccine as your first vaccine and the first booster dose. You should wait at least four months after your previous dose to get this.


Looking for a booster dose appointment in Toronto? Click here to book an appointment: Book Your Covid-19 Vaccine & Booster Dose at 1000 Bay St. (sanomedpharmacy.ca)