June 17, 2021

COVID-19 vaccination: You've got questions? We've got answers

UCalgary experts Jia Hu and Cora Constantinescu weigh in on your vaccine questions
Aerial view of the UCalgary campus
Riley Brandt, University of Calgary

With the UCalgary community returning to campus in just a few short months, we want to make sure our students, faculty and staff make this transition as safely as possible. With some people being hesitant about COVID-19 vaccines, addressing these concerns is crucial.

We asked two faculty members, Dr. Jia Hu, MD, and Dr. Cora Constantinescu, MD, both experts on vaccines and vaccine hesitancy, to answer some frequently asked questions.

Q: I’m active and in good health — is it really necessary for me to get one of the vaccines?

A: COVID-19 affects everyone differently and the effects of the disease on some individuals is more severe. It is difficult to predict how the disease will affect you — even if you are healthy — thus, vaccination is recommended for everyone who meets the eligibility requirements. Many previously healthy people get post-COVID syndrome, also known as long COVID. In addition to personal protection, vaccines also reduce the chances of spreading the virus. By getting the vaccine, you’re also protecting those around you.

Q: Of the available vaccines, which one is the safest?

A: All of the vaccines approved for use in Canada are highly effective at preventing disease, specifically severe disease and death, and are considered safe. In Canada, if you are under 30 years of age, messenger RNA (mRNA) vaccines such as Moderna and Pfizer are recommended as first choice for your first dose. Also, considering the availability of the mRNA vaccines, our province recommends you get a first-dose mRNA vaccine. What is most important is that everyone gets their first dose as soon as possible and receive the second dose when it becomes available to them.

Q: Were the vaccines rushed?

A: All the necessary steps to safely develop a vaccine have been taken in Canada. There have been no safety steps skipped or missed. There are multiple trials, phases and steps that determine vaccine safety and effectiveness. Major reasons we were able to get these vaccines developed more quickly than usual include:

  • Global effort with the world’s leading scientists focused on this task
  • Nearly unlimited resources (money, knowledge, manpower, technology)
  • A large pool of diverse adult volunteer trial participants (and the vaccines have now been tested in children ages 12 and older)
  • Large number of cases of COVID-19, therefore allowing trials to reach their endpoints quicker

Q: Do the vaccines have long-term side-effects?

A: There is currently data on the COVID-19 vaccine for 10 months post-administration and no effects occurring post-eight weeks (also known as long-term effects) have been noted. Longer-than-a-year surveillance is underway.

Q: Why are two doses of vaccine required?

A: Generally, a second dose increases the efficacy and durability (long-term protection) of the vaccine. Each time the memory cells in your immune system (generated by the first dose) encounter the same antigen (S-Protein in SARS-CoV-2, the virus that causes COVID-19), they will respond in a larger and more robust way. When those immune reactions are over, there will be a greater number of better-quality memory cells left over than there was the first time. They will be even more ready to respond fast and strong if the real virus is ever encountered. A second dose essentially “tells” your body that this was not a one-off threat, and that it is likely to encounter it again, so it better be ready.

Hu and Constantinescu are members of 19 to Zero, a coalition of academics, public health experts, behavioural economists and creative professionals working to understand, engage with and ultimately shift public perceptions around COVID-19 behaviours and vaccination.

They answered these questions and more at a recent webinar. Watch the webinar here.