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Guest Q&A on COVID-19 Vaccines

As many of us prepare for a safe return to campus, we are pleased to bring you a Q&A on COVID-19 vaccines with Dr. Maria Tokuyama from the Department of Microbiology & Immunology. Dr. Tokuyama is a viral immunologist who has extensively studied the interface between viruses and the immune system.

Note: For this Q&A, “SARS-CoV-2” is the name of the virus that causes “COVID-19”, the name of the resulting illness/disease. “COVID-19 vaccines” refer to mRNA vaccines - Pfizer-BioNTech and Moderna - which are most widely distributed in BC.

Q: How does the COVID-19 vaccine work to prevent you from contracting COVID-19?

Our cells contain DNA (the genome) that turn into mRNA that then make protein, the building blocks of life. This process happens continuously in every single cell of your body to keep you alive.

The mRNA vaccine bypasses the need for DNA to make proteins in this process, specifically the spike protein of the SARS-CoV-2 virus. Why are these spike proteins important? The outer layer of the SARS-CoV-2 virus is covered in these proteins, and the virus uses them to infect our cells. The mRNA vaccine trains our immune system to produce a large supply of antibodies that specifically bind to the spike proteins on the virus and blocks them from infecting our cells.

The immune response generated by the vaccine is not a full protective shield, it does not prevent you from contracting the virus. However, if you become infected with SARS-CoV-2, your memory immune response can rapidly clear the virus and prevent you from experiencing severe illness. Vaccinated individuals will also shed a lot less virus and for a shorter amount of time than unvaccinated individuals. This means that having vaccinated individuals will slow down the spread of the virus in the community, even if the virus is still around.   

The immune system can be similarly trained when you are infected with the virus, but this response varies a lot between individuals. The beauty of the mRNA vaccine is that most people will generate a strong memory immune response without an actual infection.

Q: Some people worry that the mRNA vaccines can somehow affect your DNA - is this possible?

No, definitely not. COVID-19 vaccines do not affect your DNA. No part of the mRNA vaccines gets incorporated into your DNA. The mRNA that contains the information to make the spike protein that trains your immune system to fight the virus. The mRNA by itself degrades very easily, which is why the mRNA is protected by a lipid nanoparticle to be synthesized, packaged, transported, and delivered into our arms. Once delivered, the lipid nanoparticles are broken up to release the mRNA into cells, so spike proteins can be made. All of these vaccine components are degraded when the cells die and the rest are cleared through the kidney.

Q: Why should I get the COVID-19 vaccine if vaccinated people can still contract the Delta variant and future variants?

You should still get the COVID-19 vaccine for these reasons:

  • The memory immune response you generate with the existing vaccines will reduce the impact of viral infection, even against the variants, compared to no immunity at all in unvaccinated individuals.   
  • We need to reduce opportunities for the virus to spread and mutate into new variants. If there are no susceptible individuals for the virus to replicate to high levels, the pandemic will eventually end.  

Q: Can immunized individuals still transmit COVID-19 to others?

Vaccinated individuals will transmit less virus if any, and for a much shorter amount of time. The overall risk and impact on the community from a vaccinated individual is much lower compared to transmission amongst unvaccinated individuals.

Q: If I had side effects to my first COVID-19 vaccine, should I receive my second dose and what can I expect?

If your side effects were mild and within what is expected for the vaccine, then it is highly recommended that you get your second dose. If you had a severe side effect after your first dose, you should consult your GP before getting a second dose.

Q: There are now antibody treatments available to those affected with COVID-19, why should I get a vaccine if I don't have the virus?

At the moment, the monoclonal antibody treatment is only available as an infusion treatment and is not an over-the-counter drug. To qualify for monoclonal infusion therapy, you must be admitted to the hospital for COVID-19 within the first week or so of disease, while the disease is relatively mild. It is not an effective treatment for severe disease. In addition, there is no guarantee that you will receive this treatment, eligibility is on a case-by-case basis and depends on timing, availability, and other criteria. On the other hand, vaccines are safe, highly effective and readily available to the general public.

Q: I have a child who is eligible for the COVID-19 vaccine. Is it true that younger people are at lower risk for serious complications from COVID-19 and, without data from long-term studies, could the risks and side effects from getting the vaccine outweigh the benefits?

Data from both the US and Canada show that hospitalization rates of children under the age of 19 have been lower than adults. However, children under the age of 19 make up roughly 20 to 25 percent of all cases in Canada, the second to the largest group of cases after the 20 to 39 age group. In BC, we are also seeing rising cases of COVID-19 in children under 19 years of age. Therefore, as the number of infections increases, we would expect the number of hospitalized children to also increase proportionally. Canadian Paediatric Society advocates for the vaccination of all children and adolescents aged 12 years and over. The long-term effects of COVID-19 (“long-COVID”) can affect a child’s quality of life for extended periods of time after infection. Given the safety and efficacy of the vaccines in children 12-17 years old and the increase in interaction with others with school back in session, there is an immediate benefit to children getting the vaccine.

Q: Will booster doses be required now or in the future? Why might we need additional boosters?

We may need boosters if our memory immune response to SARS-CoV-2 weakens or if the immune response generated by the current vaccine is no longer protective against a variant. Currently, two doses of the mRNA vaccine provide very high levels of protection against severe disease without boosters. This may change depending on how long the pandemic lasts and emerging variants.

Q: From your experience, what are the most important facts we can use in conversations with people who are hesitant about getting the COVID-19 vaccine?

We have highlighted some key points in our M&I #VaccineFacts.

  • The vaccine does not give you COVID-19 or infect you with SARS-CoV-2.
  • If you believe you have already had COVID-19, you may or may not have generated a strong immune response against the virus. What does that mean? That means you may not have sufficient levels of antibodies or T cells against SARS-CoV-2 to protect you from future exposures. This is why vaccines are still recommended for individuals who may have been previously exposed because unless you’re immune-compromised, vaccines will lead to the generation of a protective immune response. Also, recent studies show that vaccinated individuals with prior SARS-CoV-2 exposure have a superior immune response than those who were just vaccinated.
  • The lipid nanotechnology in mRNA vaccines is not new. Scientists have been developing and studying these molecules in animal models and human clinical trials for over a decade. They are very safe.
  • Even with emerging variants, there is no question that vaccine-induced immune memory is better than no immune memory at all without vaccination. 

Q: I'm excited but nervous about returning to campus and being around colleagues again. How does the COVID-19 vaccine better protect me and my colleagues against getting and transmitting the virus compared to just wearing a mask?

The protection you get from a vaccine is far superior to mask-wearing in protecting you from disease. Masks will reduce the chance of exposure to the virus and greatly reduce transmission, but they are not foolproof. If you get infected, vaccine-induced immunity is what will protect you from developing severe illness.

Q: Are there any workplace activities that should be avoided even if I’m fully vaccinated (e.g. in-person meetings, group lunches, social activities)?

Masks and vaccines are not interchangeable, their effects are additive. Masks alone will not protect you from severe disease. If you’re in a dense indoor environment and your mask is not properly worn, you can still be exposed. High-risk exposure scenarios include being physically close to an infected individual indoors without masks (e.g. eating together or talking without masks), indoor social activities that may lead to improper mask usage (e.g. lowering a mask to shout across a noisy room), and indoor gatherings of people who may not be vaccinated. While the community case rates are high, avoid these scenarios to lower your risk of being exposed to an unvaccinated individual who is infected and asymptomatic.

Q: Will the COVID-19 vaccine affect my ability to become pregnant and or be harmful to my pregnancy/baby?

Based on clinical trial data, there was no negative impact from the vaccine on pregnancy rates or pregnancy complications. However, it is well documented that viral infection during pregnancy can result in pregnancy complications, including cytomegalovirus, herpes simplex virus, and rubella, which can lead to congenital disorders. With increasing COVID-19 cases, there’s a benefit for pregnant individuals to get vaccinated to protect themselves from severe disease during pregnancy.

Another benefit of vaccination during pregnancy is that the mother transfers the antibodies generated from the vaccine to the fetus in utero. This can provide protection to the infant against the virus, even without the baby getting vaccinated. It’s a good idea to consult your OBGYN first if you have other health complications, but there is a benefit to pregnant individuals and those seeking to get pregnant to get vaccinated.

Additional resources on the vaccines:


About Dr. Maria Tokuyama, Ph.D.

Dr. Tokuyama is a new faculty in the Department of Microbiology & Immunology. She is a viral immunologist who has extensively studied the interface between viruses and the immune system. 

Dr. Tokuyama obtained her Ph.D. from the University of California, Berkeley and did her postdoc training in immunology at Yale University, where she studied the interaction between endogenous retroviruses and the immune system in the context of autoimmune disease and viral infections.  

When the pandemic hit, Dr. Tokuyama joined the Yale IMPACT Team and helped develop a rapid saliva-based PCR assay for SARS-CoV-2 called SalivaDirect, which now has FDA EUA. She has also contributed to a number of research projects on COVID-19 immune responses. At UBC, she recently gave a seminar on COVID-19 Vaccine 101 and helped with the M&I #VaccineFacts series on social media

Dr. Maria Tokuyama



  • Healthy UBC

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