COVID-19 Vaccine Questions

Creekside Vaccination Clinic

Spring is in the air and COVID-19 vaccines are slowly rolling out across Canada. Pretty soon I’ll be eligible to get a shot. Depending on your age and which province you live in, you’re probably in a similar position. Which means it’s decision time. For some people it’s an easy choice. Others will have more questions. I love questions.

Let’s start with the basics and then move onto the really interesting ones (feel free to skip ahead if you want).

What is COVID-19?

COVID-19 is a virus, a novel and particularly nasty coronavirus (and that was before we started getting the recent variants of concern). Viruses are constantly trying to enter our bodies. Our skin does a pretty good job of rebuffing them, but when they do sneak in (usually through the eyes, nose or mouth) they infect our cells and replicate.

How does our immune system fight viruses?

It’s our immune system’s responsibility to fight viruses. When viruses enter our bodies, our immune system attacks them – starting with the innate immune system and then the more specialized adaptive immune system. This leads to an immune response, like a cough, sore throat, fever. That’s not a direct symptom of the virus but our immune system doing its job.

When our immune systems fight viruses they get better at it. So the next time they see that virus they can kill it off quickly without much challenge. This is where the term immunity comes from. Unlike in video games, immunity is not a guarantee that something won’t harm you. The virus still enters your body. But if you have a healthy immune system and your immune system has already been trained to fight the virus (via a previous infection or a vaccine) than there’s a good chance it can kill off the virus without you ever noticing it.

What is a vaccine?

A vaccine is a way to train your body to fight a virus it’s never seen before. You want to give it enough training that it will effectively fight the real thing but without having to go through a full infection. There are different ways vaccines achieve this – dead viruses, mutated weaker cousin viruses, or small pieces of the original virus (like the spike protein in the case of most COVID-19 vaccines). Check out the XKCD 2425 for a great analogy explaining how mRNA vaccines work.

Does the vaccine guarantee immunity?

As stated above, immunity is not a magic forcefield. The virus still enters your body and it’s up to your immune system to fight it off. But if you’re immune system has been trained, there’s a good chance it will fight off COVID-19 without you even noticing it (65%-95% depending on the vaccine). Every COVID-19 vaccine approved in Canada has a near 100% chance of it preventing hospitalizations and death, but you might still see minor symptoms like a fever as your body fights off the virus.

Is getting the vaccine risky?

There’s a risk to everything we do. Everytime we get in the car, climb a ladder, or eat an oyster we take a risk. Every medical procedure carries some risks. Drugs we think of as safe (like Tylenol) can cause adverse reactions in rare cases (like liver failure). In most cases the risks are small and vastly outweighed by the benefit.

All of the COVID vaccines are extremely safe. You can expect pain in the arm after the injection and mild immune responses like fatigue or fever. Compared to the risks of catching COVID-19, it’s pretty benign. I created a chart below to compare the relative risks of catching COVID-19 and getting the vaccine.

If I get vaccinated, can I still spread it to others?

Part of the confusion here is the vaccine trials didn’t test for transmission risks – they only tested if people who were vaccinated got sick or not. So public health officials can’t make claims about transmission risks.

But early data shows (and common sense does as well) that vaccinations will reduce the spread of COVID-19. Just think about it. If you’ve been vaccinated, your body fights off the virus more effectively, you will be sick for less days, and there will be less virus in your body to spread. You have a 70%-95% chance of not getting sick at all. A small chance of only having mild symptoms. If the people you come in contact with have also been vaccinated, the risk is exponentially less.

This is how we end the pandemic.

What don’t we know about the vaccines?

There is a lot we still don’t know.

The vaccine trials were rushed to get something out as quick as possible. The fact that Pfizer vaccine needs 2 doses spaced 4 weeks apart and Moderna needs 2 doses spaced 3 weeks apart is not because those combinations gave the best results. It’s because that’s what they tested during Phase 3 trials and it worked, so that’s what was approved. If we weren’t in a pandemic, they probably would have tested the effectiveness of 1 does (like Janssen did) or longer spacings between doses – 6 months is standard for other vaccines but nobody wanted to run a 6 month trial.

We don’t know how long the vaccines will last. No one wanted to wait years to test it.

But is COVID-19 really that bad?

Yes. Fuck. It’s real and it’s deadly. If the statistics aren’t compelling enough for you, how about a cautionary tale. Go ask the Vancouver Canucks right now how bad COVID-19 can be. This isn’t a flu.

Data sources:
COVID-19 Epidemiology Update – Public Health Agency of Canada
COVID-19 signs, symptoms and severity of disease – Public Health Agency of Canada
Canadian COVID-19 vaccination coverage report – Public Health Agency of Canada
Reported side effects following COVID-19 vaccination in Canada – Public Health Agency of Canada
Coronavirus (COVID-19) Cases – Our World in Data
Pfizer BioNTech COVID-19 Vaccine Fact Sheet – FDA
Moderna COVID-19 Vaccine Fact Sheet – FDA
Management of post-acute covid-19 in primary care – TheBMJ
Comparing vaccines: efficacy, safety and side effects – Healthy Debate

Disclaimer: I’m not a medical expert. I’m sure I got a few details wrong or overly simplified something. If you see anything particularly egregious, feel free to let me know.

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