“i got AstraZeneca for my first dose. Which vaccine is best for my second?”

Choose your vaccine based on this

  1. Getting AstraZeneca for your first dose was the right decision. It’s protecting you and others from severe Covid-19.
  2. Now, it’s most important to get a second dose of any vaccine. Any second dose helps you be fully immunized and protects you better against the variants.
  3. Deciding on either AstraZeneca or Moderna or Pfizer* for your second dose:
    *Moderns and Pfizer have similar benefits and side effects. It doesn’t matter which one you get.


  • A second dose of AstraZeneca may offer less protection against the variants than Moderna or Pfizer.
  • It might be best to get AstraZeneca now if you have to wait several weeks for Moderna or Pfizer.
  • The risk of a severe blood clotting disorder from the second dose of AstraZeneca is estimated to be 1 in 600,000.
    *This number may change as we learn more.

Moderna or Pfizer

  • A second dose of Moderna or Pfizer may offer more protection against the variants than AstraZeneca.
  • Canada has a large supply of Moderna and Pfizer. They may be easier to find than AstraZeneca.
  • There is no known risk of blood clots with Moderns or Pfizer.
  • With any vaccine you get for your second dose (AstraZeneca, Moderna, or Pfizer), you may feel more, the same, or fewer side effects than your first dose. Side effects can include a sore arm, fatigue, headache, body aches, and chills for 1-3 days.

Rest, fluids, and acetaminophen can help with common side effects from all vaccines. Some people may need to take 1-2 days off from usual activities.

This can be a tough choice. If you have questions about getting your second dose, ask your healthcare provider.