What uOttawa experts want you to know about the COVID-19 vaccine

Posted on Wednesday, June 30, 2021

A syringe inserted into a vial of vaccine.

By the end of June 2021, more than 65 per cent of Canadians had received their first vaccine against COVID-19. While the country ramps up its efforts to get more needles in arms, many people still have questions.

To help answer these questions, the University hosted two roundtables with some of our experts last month. 

Below you will find some information shared at these events by Professor Raywat Deonandan, from the Faculty of Health Sciences, along with Professor Colleen M. Flood, from the Faculty of Law, Common Law Section, and Professor Marc-André Langlois, of the Faculty of Medicine.


Marc-André Langlois, Colleen M. Flood and Raywat Deonandan.

From left to right: Marc-André Langlois, Colleen M. Flood and Raywat Deonandan

Is everyone equally protected by the vaccine?

With effectiveness hovering at around 95%, these vaccines promise to protect us against the most serious symptoms of COVID-19. However, as Professor Deonandan pointed out, their rate of effectiveness after mass vaccination campaigns tends to be lower than what is observed in clinical trials. Why? Because the immune response varies between different people, most notably due to age and underlying health conditions.

Professor Langlois went on to explain that while most people exhibit a very good immune response to the vaccine (i.e., their antibodies react optimally four weeks after they receive their second dose), some people do not react as well, and these people are only partially protected. Unfortunately, a lab test is the only way to tell for sure what your immune response might be.

So, the golden rule is to continue being careful while the virus is present in the community and herd immunity has not yet been reached, even if you have received both doses of a vaccine.

What is herd immunity?

Herd immunity is reached when enough individuals are immunized. At that point, the virus has a hard time finding new hosts to infect, which slows down its spread considerably. To reach herd immunity, a significant proportion of the population must be vaccinated.

The level of herd immunity required to protect against COVID-19 also depends on the effectiveness of the vaccination against new and emerging variants. Evidence suggests that a higher level of herd immunity will be required to protect against the Delta variant, for example.

People need to understand that a vaccinated person can still contract and transmit the virus, but in much lower incidences than a non-vaccinated person. Scientists now agree that someone who is vaccinated and has the virus has less of a chance of infecting someone whose immune response is insufficient or who has not yet received the vaccine. In other words, getting vaccinated allows us to protect ourselves as well as those around us.

Is it safe to get vaccinated?

Many rigorous processes are required before any vaccine is approved for distribution in Canada. Professor Flood explains that the COVID-19 vaccines are not exempt from these processes and that the speed at which they were made available does not reduce their safety.

The data being collected during this kind of mass vaccination is crucial and will allow researchers to learn more about side effects that may not have been observed during clinical trials.

While people may be nervous about side effects, it is important to put them in perspective. When we compare the potential side effects and risks associated with different vaccines to those of contracting COVID-19, vaccination is clearly the better option from a scientific perspective.

Will proof of vaccination now be required?

The idea of a vaccine passport, or being required to show proof of vaccination, continues to be controversial from an ethical standpoint, even though it is not a new concept. Professor Flood reminds us that proof of vaccination is required to attend school in Ontario, and that proof of yellow fever vaccination, for example, is required to enter certain countries. What is different in this case is the digital nature of the proof and the universal application of the measure, which raises concerns relating to access, privacy and discrimination, among other issues.

International travel is currently subject to many restrictions. Some countries have temporarily closed their borders, while others are asking for proof of vaccination and a negative COVID test to enter, sometimes imposing a quarantine upon arrival.

Requiring a vaccine passport instead of these harder requirements is an obvious policy imperative. Indeed, the Canadian government has recently announced it will eliminate quarantine requirements for returning Canadians who have been vaccinated.

More delicate questions emerge as to whether proof of vaccination should be required as a matter of employment or, for example, to return to schools or universities. Existing Charter laws and human rights laws protect those who can’t be vaccinated because of disability or age but likely will not protect those who merely object to having to show proof of vaccination.

One dose, two doses, booster shots?

The consensus on this topic is clear: if the vaccine requires two doses then two doses are key to ensuring an optimal immune response. But for how long?

Scientists do not yet know exactly how long the COVID-19 vaccines protect against the disease. According to current information on the benign coronaviruses that cause seasonal colds, antibody immunity is expected to last at least 12 to 18 months. An analysis of the decline in antibodies in individuals who have contracted the virus at the start of the pandemic seems to indicate that immunity from COVID-19 will be about that long.

However, Professor Langlois specified that the immune system is not an on/off switch. Although we may preserve a certain level of immunity for a long period, this immunity tends to diminish over time and may not efficiently protect against new variants. A booster vaccine renews your level of protection and can be customized for the circulating variants. According to preliminary analyses, we can expect to receive a booster vaccine every year, like it’s the case with the flu shot, if the virus continues to generate new variants.

If you find that your questions weren’t answer here, send us an email with your inquiries or visit uOttawa's coronavirus information website

You can also visit the Government of Ontario’s website and the Government of Quebec's website for more facts about vaccination. 


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