Reopening, first dose protection and more: Some of your vaccine questions answered

As more people get their first dose of the vaccine to protect against COVID-19, more questions are coming up. 

People 35 and up can be vaccinated beginning Thursday morning but many people are still waiting for their second dose. For some answers, CBC reached out to Alyson Kelvin, a virologist at the Vaccine and Infectious Disease Organization-International Vaccine Centre in Saskatoon. 

The following conversation has been edited for length and clarity. 

How protected are you after one dose?

Kelvin: We want to know if we can open things up after the first dose, but really, you are fully protected after the second dose. Some data is coming in showing that there are high levels of protection after the first dose. The estimate is between 70 and 92 per cent effective after one dose.

We don't know how long that protection lasts after the first dose, which is why you're seen as fully protected after you have those two doses.

For people waiting patiently for the second dose, how long does that protective immune response last?

We don't really know. Some studies have been done and it seems that you do have high levels of antibodies after two months, but it's going to take time for us to figure that out."

Canada has put their interval at up to four months between shots. Are we seeing any issues because of this recommendation?

Well, it's quite interesting as a vaccinologist and virologist, we've known for a long time that the longer you wait between your first dose and your second dose of a vaccine, actually you have better protection in the long run. You just have this gap in the middle.

So I don't think delaying your second dose is really going to affect your overall protection when you receive your second dose.

Is there a threshold where we could safely ease restrictions and consider ourselves, as a community, reasonably protected by vaccines?

I think what we need to be looking for is the number of cases that we're seeing per day and our averages per week. When we see that start to drop, then we can determine if that's associated with the number of people vaccinated.

Are we having that decreased transmission? Are people ultimately being protected? I think that's what we need to be looking for when we start forming public policy. 

Is a person's reaction to the shot at all correlated to how they would have reacted to actually getting COVID-19?

I think the way you respond to a vaccine and the way you respond to a viral infection are two totally different things. A vaccine is supposed to help your body learn what a virus looks like without you having to be infected.

But, of course, the virus infects you and kind of utilizes your body for its own means. So there's two different purposes for a viral infection and a vaccination. And really how you respond to each of them probably aren't associated at all.