What You Should Know About COVID-19 Vaccines

| COVID-19

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Welcome to the second article in Bayshore’s “Be Our Guest” series. This month, we invited Dr. Michael Gardam, a specialist in infectious diseases, to answer commonly asked questions about COVID-19 vaccines. Dr. Gardam is the Chief Operating Officer at Health PEI, the health authority of Prince Edward Island. He is also the head of infection prevention and control at Women’s College Hospital in Toronto, and director of the tuberculosis clinic at Toronto Western Hospital.

Q: Dr. Gardam, how long have you specialized in infectious diseases?

A: Since 1998, when I got my medical license. I’ve seen patients my whole career, but my practice is more about public health and preventing the spread of infection. Working on things like pandemics is my specialty. I’d just started working at University Health Network in Toronto when SARS happened. It was my first year or two at my job


Q: So far, Canada has approved two vaccines for COVID-19. How do the Pfizer and Moderna vaccines work, and how are they different?

A: Both vaccines are messenger RNA (mRNA) vaccines. They instruct our cells to make a protein, or part of a protein, that triggers an immune response, which in turn produces antibodies against the virus. The Pfizer and Moderna vaccines are practically identical in how they work – they both instruct the body to produce a spike protein like the one on the surface of the COVID-19 virus. The difference is that they use different particles to suspend the mRNA. In the coming months, as more vaccines are developed, we’ll see four or five other technologies. Astra-Zeneca’s vaccine uses a modified cold virus. Others use manufactured spike proteins.


Q: Why do the Pfizer and Moderna vaccines each require two doses?

A: The easy answer is: that’s how they were studied. These companies have really smart people, and what they’re trying to create is long-lasting immunity. Over the years, with other vaccines, they’ve learned that multiple doses makes immunity last longer. So, for example, the vaccine for chickenpox is two shots. The vaccine for hepatitis B is three shots. The scientists reviewed the COVID-19 virus and what kind of immune response it causes, and that suggested to them that two shots will lock in the immunity. That being said, Novavax recently posted strong results from their vaccine trial, and it’s only one shot. So not every vaccine will have two shots. Some could theoretically have more than two – whatever the scientists believe will give them the biggest bang for their buck.


Q: What are the side effects of the Pfizer and Moderna vaccines?

A: The side effects are usually mild and similar to those of other vaccines: soreness around the injection site, and flu-like symptoms: feeling tired or feverish, body chills. Four million people have been vaccinated so far, and there are no serious side effects except very rare cases of anaphylaxis, which happens with all vaccines, and exceedingly rare cases of facial paralysis. However, the risk of serious illness from COVID-19 is far greater. I would still get vaccinated.


Q: Do the vaccines prevent us from catching COVID-19, or only from getting sick?

A: It’s not known yet. In studies, people received either the vaccine or a placebo, and people who got the vaccine didn’t get sick – but they weren’t tested to see if they got infected. That’s why it’s still important to practise other safety measures. Early data from Israel, which is using Pfizer’s vaccine, suggests that vaccination stops infection. We’ll know more over time.


Q: Will we have to get vaccinated for COVID-19 every year, like we do for the flu?

A: Nobody knows yet if the vaccine is one-time or will require doses every year, every two years or longer.


Q: Some people are worried that the vaccines were developed too quickly, without sufficient testing for safety and effectiveness. What are your thoughts?

A: It isn’t true, but it’s a bit nuanced. These are new vaccines, and they’ve only been tried in people over the past six months, so we have six months of safety data.


Q: Some people are worried about the effects of the genetic material in the vaccines. Can you comment on that?

A: The vaccines expose you to a snippet of genetic material from a virus, and your body provides the protein that triggers the immune response. What happens when you’re exposed to other viruses? Your body produces the whole virus – yet nobody worries about the long-term safety of catching a cold. There’s no reason to think that the COVID-19 vaccines will cause long-term side effects. People say, “Oh, it’s a foreign material,” but you’re exposed to foreign materials all day long. The mRNA technology has been in development for years, and many other vaccines also expose you to genetic material and viruses. Think of it like this: in the old days, computers had punch cards that went through the system. Your body is the computer, we’re giving you a punch card, and your body is doing what that punch card says – in this case, make a spike protein. The card doesn’t get incorporated into the computer.


Q: What other concerns or misinformation do you hear often?

A: One of the biggest ones is that the government rushed through approvals and didn’t properly study the vaccines. That simply isn’t true. All of the normal steps done to approve a vaccine were followed – it’s just that they’ve cut through the bureaucratic delays. It usually takes months for the federal government to approve a new product or device, but if you know something is of worldwide importance, it’s not going to sit on your desk – you’ll jump on it immediately. They still went through all the steps. There was no cutting of corners. They just cut all of the wasted time.


Q: If someone has already had COVID-19, do they need to get the vaccine?

A: The official answer is yes, get vaccinated. There’s no harm in getting vaccinated. The longer answer is that we don’t know how long the immune response lasts after you’ve had COVID. If you’re in a high-risk group, you should get vaccinated, because we’ve studied the body’s response to the vaccine, but we don’t yet understand its natural response to the virus.


Q: Is there anyone who shouldn’t get a COVID-19 vaccine?

A: There are not really a lot of contraindications to getting the vaccine. If you’re pregnant or breastfeeding, the vaccines weren’t studied in that population, so you need to talk it over with your health-care provider and make an informed choice. There’s nothing inherent in the Pfizer and Moderna vaccines that should cause problems in pregnancy. Over time, we’ll know more, as more pregnant women around the world get vaccinated. If you’re highly immunocompromised, the vaccine won’t harm you – it’s not a live virus – but it may not be as effective.


Q: Do the Pfizer and Moderna vaccines offer protection against the new variants of the coronavirus recently detected in Canada and elsewhere around the world?

A: Yes. There are multiple variants of concern, or VOCs. Hundreds have been identified so far, and the three everybody’s talking about are the U.K., Brazil and South Africa variants. The South Africa variant, the vaccines don’t work as well, but they’re still more effective than, say, the annual flu shot. Over time, as the virus continues to circulate, we’ll have to change the vaccines. That’s totally predictable and expected – it’s evolution at work. Right now, nobody needs to panic. Six months or a year from now, Pfizer and Moderna may start to retool the vaccines, if other variants are emerging and starting to become really important.


Q: Once someone has been vaccinated, can they stop wearing a mask and practising physical distancing?

A: No, they can’t, for two reasons: we haven’t yet proven that being vaccinated means you can’t get infected and can’t pass it on. It would be really dangerous to stop the other safety measures. If we vaccinated everyone working in long-term care, what if it turns out they can still get infected and spread it where they work? Until we know for sure that being vaccinated prevents infection, not just getting sick, we should err on the side of caution and continue to follow public health measures. Plus, nobody knows if you’ve been vaccinated or not. If you don’t wear a mask, they’ll think you’re walking around spreading the virus.


Q: How long will we all have to continue practising physical distancing and other safety measures?

A: Once 65% or 75% of the population has antibodies, it’s hard for the virus to make people ill. We’ll learn more in the next few weeks, when we know if the vaccine is a dead-end for the virus or if it can still be passed on. I’ve been predicting a somewhat normal summer. I think we’re halfway through the pandemic.


Q: Is there anything else that people should know?

A: I joke with the media that a lot of the stories are spreading faster than the virus itself – all the hype about the new variants and this and that. The media is more concerned than the scientific community. When you talk to people who are in the know, they’re watching these things, but they’re not panicking. We’re on track, we know how to control this, and we know that public health measures work. We know masking works, and the new vaccines work shockingly well. The new variants are of no public significance, but they are being watched. They may become significant over time, but people should not get caught up in all the hype we’re hearing and just know we have a plan and it’s being followed. Even the delays in Pfizer’s vaccine delivery – these are minor blips that were totally expected. We’ll have millions of doses by the spring, and the problem then will be that we can’t get it to people fast enough.


For the latest information about COVID-19 vaccines, please refer to the Government of Canada website