Ask the expert: your COVID-19 vaccine questions answered
Ryerson expert Jordan Tustin helps community members cut through the noise by answering frequently asked questions about the COVID-19 vaccines. Photo by Alyssa K. Faoro.
Most of us probably never expected conversations about viruses and vaccines to become such a prominent part of our daily lives. But here we are, 18 months into a pandemic and still trying to make sense of this constantly evolving situation.
Amidst all the confusion, one thing that experts say for certain is that the only way out of this pandemic is together. Each of us has the power to help stop the spread of COVID-19 and through collective action, we can hope for a faster return to normalcy.
Although more than half of Canada’s population is now fully vaccinated, many people probably have unanswered questions or are feeling nervous about the new vaccines.
So, we reached out to the Ryerson community through social media to ask directly: what are your top vaccine-related concerns?
Below, Ryerson professor Jordan Tustin answers the most frequently asked questions we received.
A field epidemiologist with a focus on communicable diseases, Tustin has extensive experience working in public health and investigating outbreaks at the local, provincial, national and international levels. Her research interests include communicable disease epidemiology, field epidemiology, global health and vaccinology.
The short answer is yes, but you are less likely to become infected and the vaccine will protect you from serious illness.
Recent national data show that since the start of the vaccination campaign in December 2020, approximately 90 per cent of COVID-19 cases have been among those who are not vaccinated. Fully vaccinated Canadians were 69 per cent less likely to be hospitalized and 49 per cent less likely to die compared to unvaccinated Canadians.
Getting vaccinated will protect you from getting seriously ill and dying but no vaccine is 100 per cent effective. Although rare, ‘breakthrough infections’ can sometimes occur.
It’s important to remember that the vaccines themselves cannot cause COVID-19, because they do not contain the SARS-CoV-2 virus responsible for the disease.
We are also still learning about the variants of concern and whether the vaccines are as protective against these new strains. For this reason, and because some age groups remain unvaccinated (children under 12 years) and are at risk of infection and transmission, it is important to continue to follow your local public health recommendations and take precautions even if you’re fully vaccinated.
For two-dose vaccines, you need both doses to gain the highest level of immunity possible.
After the first dose, there is a good immune response that kicks in within two weeks and the second dose boosts this immune response for even stronger long-term protection, generally within two weeks after vaccination with the second dose. During this time, it is important to keep taking all precautions to avoid infection.
There is no evidence that people who get only one dose have adequate long-term protection against COVID-19 infection.
Here’s how the vaccines work and no, they do not change your DNA.
There are two categories of COVID-19 vaccines approved in Canada: mRNA and viral vector vaccines.
Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines that teach our cells to recognize the antigen proteins found in the coronavirus. They trigger our immune system to make antibodies and fight the antigens when exposed to the virus. The mRNA vaccines do not change your body’s DNA (genetic material) – it is not possible for mRNA to enter the nucleus, the part of a cell that contains our DNA.
The AstraZeneca and Janssen vaccines are viral-vector vaccines. They use a harmless virus, in this case the adenovirus, as a delivery system to instruct our body to produce spike proteins that can respond to the SARS-CoV-2 virus.
Spike proteins produced by either mRNA or viral-vectors do not contain the virus and you cannot get infected with COVID-19 from either vaccine type.
The main benefit of these vaccines is that you will get protection without putting yourself at risk of serious health consequences that result from getting infected with COVID-19.
We don't know yet, and maybe.
As with any new vaccine, the effectiveness of the vaccines in real-world settings will only be known after widespread use. The duration of protection will not be known immediately – this requires time – and will likely vary by vaccine, age and pre-existing medical conditions.
Studies are ongoing to determine the duration of vaccine efficacy and effectiveness on variant and non-variant strains. Thus, the degree to which these vaccines provide long-term immunity, and the need (or not) for additional booster vaccines will be studied and determined going into the future. Public health officials will decide if and when boosters will be needed based on scientific data.
Yes. If you had Pfizer or Moderna for your first dose, it is safe and effective to have either mRNA vaccine for your second dose.
In Canada, the National Advisory Committee on Immunization (NACI) that comprises various vaccine experts, advises health authorities on the use and safety of vaccines. Their direction is evidence-based and targeted to Canada’s situation and needs.
Based on principles of sound vaccinology, NACI has stated that mRNA vaccines are interchangeable as they function in the same way, and have very similar efficacy and side effects. They also stated there is no reason to believe that mixing and matching of the vaccines would produce any additional safety issues or reduce protection.
NACI has also recommended that those who received AstraZeneca for the first dose should receive an mRNA vaccine for the second dose as preliminary data indicate a stronger immune response from mixing the two vaccines than from two doses of AstraZeneca. However, those with two doses of AstraZeneca are considered fully immunized and do not need an additional dose.
NACI is currently monitoring the evidence on mixing COVID-19 vaccines and will update any recommendations as needed. It’s important to note that interchanging vaccines is not a new concept and vaccines from different manufacturers have been used in the past for other diseases, such as influenza and hepatitis A, when the vaccine supply and/or public health program or priorities have changed.
There can be side effects from vaccines but there is no strong evidence to suggest that side effects are worse from mixing doses.
Everyone’s immune system responds differently to vaccines, so this is why you might be hearing varying stories on side effects from your friends and family. I have friends and family who felt nothing and a small number who experienced mild flu-like symptoms for a few hours to a couple of days. Side effects could include symptoms such as pain at the site of injection, body chills, fatigue and mild fever that do not pose a major risk to health.
Side effects are normal signs that the vaccine is working and your body is building protection. But not having side effects is also completely normal as people react differently, so having no side effects does not mean that you are less protected.
Personally, I had AstraZeneca for my first vaccine and Moderna for my second. I typically do not have side effects from vaccines but I did experience mild side effects this time, and the same for both – pain at the site, chills, sweats, mild fever, headache – for a couple of days.
Taking care of yourself through rest and hydration, and medicines that relieve your symptoms will help, such as Acetaminophen and Ibuprofen. But remember, if you do get side effects (and you might not), they will be short-lived and you will have protection against the serious health consequences of COVID-19.
On a personal note, and what I always tell my students, I get vaccinated (whether it’s for routine immunizations, seasonal flu or COVID-19) not just for myself but also to protect others who might not be able to protect themselves.
There are people who may not be able to get vaccinated for medical reasons, have access issues, are currently not eligible (i.e. children) and/or are immunocompromised and at risk of more severe illness. Having said that, if you are personally having access issues, please contact your medical doctor or local public health authority to find a solution.
Good question and an important one that deserves more time than the answer below.
Vaccine hesitancy is a complex issue and the reasons for hesitancy can vary across populations, vaccines, contexts and time. Vaccine hesitancy has been a growing problem, long before COVID-19, and it is important that we address an individual’s specific concerns and questions in a transparent manner. Vaccine hesitancy can lead to lower vaccine uptake in a population, compromising our ability to achieve herd immunity, which can then cause outbreaks of the disease in an unvaccinated population – and serious consequences such as hospitalizations and deaths.
It is understandable to have questions, concerns and anxiety when it comes to vaccination, specifically for a new vaccine. Unfortunately, there is widespread transmission of misinformation and myths about vaccines, and this has become significantly more widespread and prominent for COVID-19 vaccines.
It is important that you are seeking out information from trustworthy sources – which can often be a challenge when misinformation, myths or fake news is circulating widely. Some trustworthy sources could be your doctor or another health care professional, your pharmacist, public health authorities, professionals and their associated websites and communications, or peer-reviewed scientific journals.
Learning to sort through the misinformation, myths and fake news on social media can also be a great challenge. I recommend visiting this fantastic resource (external link) developed by a Ryerson team from the Social Medial Lab (external link) and Ted Rogers School of Management, that puts a spotlight on COVID-19 misinformation, how to stop misinformation from spreading, and real-time factual COVID-19 information.
No. All vaccines approved for use in Canada are safe and effective.
Unfortunately, there has been confusing communication about the vaccines and their safety, but here is why we can feel safe.
Health Canada’s independent drug review process is recognized globally for its high standards and is based on solid scientific and medical evidence. The currently approved COVID-19 vaccines underwent this rigorous review and were approved as safe and effective.
It's true that developing a new vaccine and its subsequent approval can take years. However, the approval of COVID-19 vaccines progressed more quickly due to major advances in science and technology, extensive international collaboration among scientists, industry, researchers, health professionals and government, and increased dedicated funding in vaccine development and processes.
Large clinical trials are required to determine if vaccines are safe and effective, and there are strict evidence requirements that must be met. Typically, the vaccine development process involves a number of clinical trial phases. For potential COVID-19 vaccines, processes have been fast-tracked to decrease the time between trial phases, thus speeding up development and approvals without compromising vaccine safety and effectiveness.
Health Canada implemented a fast-track review process to assess COVID-19 vaccines, reviewing any new evidence as soon as it became available. They followed all the usual rigorous regulatory processes, and approval decisions were based on independent evaluation of the scientific data that show the vaccine is safe, effective and of good quality, and also demonstrates that its benefits outweigh the risks.
Health Canada has enhanced processes in place to monitor any real world adverse effects – for all approved vaccines and medications. It closely monitors the safety of COVID-19 vaccines and immediately responds to and assesses any safety issues. Canadians are informed of any risks that arise.
The Canadian government is also releasing weekly online public reports (external link) on any investigations of potential adverse events following immunization (AEFI) that Canadians may have experienced after receiving a COVID-19 vaccine. If a vaccine is suspected to cause a rare serious side effect, health authority experts conduct a thorough investigation and evaluation. This can lead to measures such as suspending the use of the vaccine or specific lots of the vaccine while the risk is investigated.
No, they are different viruses with different vaccines specific to that virus. One does not impact the other, nor does one vaccine provide you with any protection from the other disease (COVID-19 vaccine will not protect you from the flu and vice versa).
There is no issue with having both vaccines and I would strongly encourage you to receive the flu vaccine this fall/winter as we know there are similar symptoms to COVID-19 and the flu can also have serious complications such as hospitalization and death.
There is evidence that shows immunity levels differ among people who were infected with COVID-19 (acquired immunity) and so they have different levels of protection.
We don’t know how long immunity will last after someone was infected with COVID-19. Re-infections have been documented and there is no guarantee that a person who had COVID-19 cannot get it again. So, it is important to get vaccinated even if you know you were infected with COVID-19.
There have been anecdotal reports, mostly via social media, that the vaccine has caused irregularities in menstrual cycles. There is ongoing research but no conclusive link. It is important to note that other factors such as stress, nutrition and anxiety can affect menstruation cycles.
There is no scientific evidence that the COVID-19 vaccines impact fertility in women or men. This is a circulating myth. The COVID-19 vaccines do not contain anything or affect anything that would be capable of doing this.
Simply, to protect you.
Aluminum salts (e.g. aluminum hydroxide) have been used safely in vaccines such as diphtheria and tetanus for over 70 years. These are used as an adjuvant, which is an ingredient in some vaccines that will help produce a stronger immune response.
Aluminum is one of the most common metals and is found everywhere in the environment – in food, water and air. We eat aluminum every day and an infant will be exposed to more aluminum from breast milk and formulas than from vaccines. This consumption is at a safe amount.
The amount of aluminum salts found in some vaccines is low, regulated by Health Canada, and not readily absorbed by the body. The safety of aluminum salts in vaccines has been well established.
You can find more information about the use of Aluminum as an adjuvant in some vaccines here: https://immunizebc.ca/infographic-vaccine-safety/story_html5.html (external link)
No, there is no evidence to suggest that the vaccines are damaging or toxic to our organs.
The spike protein created by the vaccines is harmless – it remains attached to the cell surface, around the injection site, and does not travel to any other organ in our body. This is a myth propagated on social media with zero evidence to support the claim.
I think this question pertains to a video that has been shared thousands upon thousands of times on social media. No, this is a conspiracy theory. There is absolutely no truth to this. The vaccines go through a strict and transparent regulatory process and they wouldn’t even work if there were microchips.