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COVID-19

What is it?

COVID-19 is a disease caused by SARS-CoV-2.

SARS stands for severe acute respiratory syndrome. CoV means coronavirus, which is a family of viruses. 

Common symptoms include fever, chills, cough, loss of taste or smell, fatigue (tiredness), difficulty breathing, and muscle aches.

What's the difference between them?

Pfizer and Moderna are mRNA vaccines, while Johnson and Johnson and Novavax are viral vector vaccines.

For information about these types of vaccines, click here.

Pfizer and Moderna are recommended for people as young as 6 months old. Novavax is approved for ages 12+. Johnson and Johnson is approved for people over 18. 

The schedule depends on the vaccine and whether you have already been vaccinated against COVID-19

Pfizer (Comirnaty) - Bivalent:

  • 6 months - 4 years:

    • If not previously vaccinated: Three doses (3 weeks between dose 1 and 2, 8 weeks between dose 2 and 3)​

    • One previous dose of monovalent vaccine: two additional doses (started at least 3 weeks after the original dose and 8 weeks between doses)

    • Two or three previous doses of monovalent vaccine: one additional dose (at least 8 weeks or 2 months after the last dose)

  • Ages 5+:

    • One dose (with an option for a booster for 65+ 4 months after dose 1)​

    • People who have previously received a monovalent vaccine can receive a bivalent vaccine two months after their last dose 

Moderna (Spikevax) - Bivalent:

  • 6 months - 5 years:

    • If not previously vaccinated: Two doses (1 month between doses)​

    • One previous dose of monovalent vaccine: one additional dose (1 month after the original dose)

    • Two previous doses of monovalent vaccine: one additional dose (at least 2 months after the last dose)

  • Ages 6+:

    • One dose (with an option for a booster for 65+ 4 months after dose 1)​

    • People who have previously received a monovalent vaccine can receive a bivalent vaccine two months after their last dose 

Novavax: 

  • Novavax requires two doses 3 weeks apart

  • Boosters are approved for ages 18+

Jannsen (J&J):

  • This vaccine only requires one dose and is approved for ages 18+

  • This vaccine is only recommended for people who cannot receive other COVID-19 vaccines or who otherwise would not get vaccinated

Relevant Terms

  • Bivalent: protects against two versions of a pathogen

  • Monovalent: protects against one version of a pathogen

  • mRNA: Messenger ribonucleic acid (mRNA) is a form of genetic material that acts as a template to make proteins.

  • Viral vector: a version of a virus that has been modified to contain genetic information from another source (in this case, the genetic information to make the spike protein). 

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