Do we need booster shots?

Editor’s note: The U.S. will be making booster shots of the COVID-19 vaccine available for all adults starting next month. Will Canada follow suit? Healthy Debate Editor-in-Chief Seema Marwaha talks about how the shots could help protect the immunocompromised – especially during the fourth wave – and, perhaps later on, the general public. This Q&A is adapted from a CBC interview broadcast on multiple CBC radio stations.

What kinds of medical conditions cause you to be immunocompromised? 

Being “immunocompromised” means that your immune system does not respond as briskly to infections, making them more challenging to treat. It also means you might not mount a strong antibody response to vaccinations.

It’s a heterogenous term that encompasses many different medical conditions. Some people have congenital conditions that weaken their immune response. They could have an illness, like a blood cancer, that suppresses immunity. And many Canadians with auto-immune diseases like lupus or rheumatoid arthritis are on strong immunosuppressive drugs. They also might be on powerful immunosuppressants if they are transplant recipients.

The immune system is complex, with multiple components including antibodies and white blood cells, so each immunocompromised person might respond differently to the COVID vaccine.

If you have a weakened immune system but are also fully vaccinated, are you protected from COVID-19?

Unfortunately, there are a few studies that indicate vaccines might not work as well if you are immunocompromised or on immunosuppressive drugs. But they also suggest that additional booster shots can make the vaccine work better in some of these individuals.

Immunocompromised individuals were largely excluded from the first vaccine trials, so there was some degree of uncertainty as to how they would response. But in most cases, the benefits of the vaccine vastly outweigh any unknowns because immunocompromised individuals with COVID have the potential to develop a more severe illness.

A Toronto University Health Network study “shows a clear benefit” of a booster shot for organ transplant recipients. On August 17, Ontario announced that it was making booster shots available for vulnerable populations, including transplant recipients.

After a French transplant study showed similar results, France began offering boosters to immunocompromised individuals.

I will say that we don’t know what antibody response is needed for protection and the immune system has many other components than antibodies that is uses to fight infection, so this is just a piece of the puzzle.

There is an ongoing Canadian study looking at people with rheumatoid arthritis and lupus specifically.

What extra measures or precautions should those with weakened immune systems keep in mind?

There may be ways to make the vaccine more effective that are currently being trialed.

One is for patients to hold off their immunosuppressive medications for weeks or months to give the vaccine time to take effect. But there is a risk of transplant rejection and disease flare ups during these drug holidays. Another is a booster shot of the vaccine.

Immunocompromised patients – even in places where restrictions have been lifted – should adhere strictly to public health guidelines of masking indoors and in public places, practice social distancing and avoid mixing households and potential super-spreader events, especially if they are in an area with rising community case rates.

If you are immunocompromised and get COVID, you are at a much higher risk of hospitalization and severe illness. You also might shed the virus for longer, giving the virus a chance to mutate. This could be bad for everyone if new variants arise that can evade the vaccine.

If I have a friend or family member who is immunosuppressed, is there anything I should do differently when spending time with them?

First and foremost, the way to best protect any vulnerable or unvaccinated group is to get everyone who is eligible vaccinated. This gives the virus fewer potential hosts and will reduce community spread. It’s our major competitive advantage over the virus. The vaccine does more than prevent individual transmission. We can strive toward herd immunity to protect vulnerable people

I know we are all tired of the extra precautions, but in this group, they are necessary in some circumstances. If you share a household with someone who is immunosuppressed, be hypervigilant. Especially in areas with high case rates. Mask indoors and practice social distancing.

Each activity or gathering has a risk-benefit calculation you need to make for yourself. If someone is immunocompromised, know that they can get severely ill if they contract COVID. Opt for distanced and outdoor activities and limit mixing of households to reduce exposures.

Will Canada introduce COVID booster shots for other Canadians? Wouldn’t we all benefit from a third shot?

Canada is not pushing ahead with booster shots just yet, citing limited evidence. Theresa Tam, the chief public health officer of Canada, has said she is watching the situation carefully. Canada is not seeing many breakthrough infections yet, but plans are being made to implement a booster if necessary. Many experts feel that for most people, the vaccine is doing its job. Another dose and more antibodies in most people might make no practical difference.

In Quebec, however, the province has authorized a third dose for people who want to travel to countries that don’t recognize people as fully vaccinated unless they received two doses of the same vaccine.

In the U.S., the administration has announced that the first booster shots will be administered beginning in September and will go to nursing home residents, health-care workers and emergency workers, followed by other older people and then the general population.

Israel’s Health Ministry has recommended dropping the age of eligibility for a COVID-19 vaccine booster to 50 from 60.

Ethically, is it right to start giving third doses to Canadians when much of the world remains unvaccinated? Would this take away shots from vulnerable people?

The World Health Organization has called on countries to delay offering booster shots until the end of September and allow every country to vaccinate at least 10 per cent of its population.

Among the groups that might be prioritized for a booster are the immunocompromised, those who received less effective vaccines – like the J&J or the Sinovac abroad. And older individuals where there is a question of a waning immune response.

But as with everything over the past 18 months, I’m sure this will all evolve in time as we learn more. The debate is sure to arise during this federal election campaign.


Further reading:

The comments section is closed.

  • Ratrional Doctors says:

    As a physician, I have fought against professional support of mandates within my specialty. My original stance was “its experimental, medical ethics (Nuremberg)”. I watched in horror as my well-meaning colleagues quickly forgot about ethics once the propaganda campaign ramped up. They argued “the public good demands flexibility toward ethical stances”

    My next stance was “it is experimental as evidenced by the fact there are more documented risks and less documented benefit than there were 3 months ago, and you can’t tell me that 3 months from now that trend won’t continue.” Their response was “the fact that the vaccine is only partially effective means everybody has to take it – to prevent spread” I pointed out that the math behind that logic made a difference on the order of 1:10,000 to 1:100,000 deaths. Some were moved, but many were not.

    Now my stance is “the vaccinated are now catching spreading the disease at higher rates than the unvaccinated.” Now, I’m watching even the most ardent Mandaters retreat back to “yeah, but hospitalization and deaths are fewer, so we need to keep promoting it”….the calls for mandates are weakening as the spread argument dies and what we are left with is only a matter of personal freedom and risk assessment.

    At this stage, the official stance is one that “supports mandates” but makes it clear that medical, religious and matters of conscience must be honored ethically and without consequence. So, it’s basically a matter of face-saving semantics but the final result is “you get it if you want, we think you should want to, but it’s up to you”.

    I’ll be very curious to see what deaths and hospitalizations do in the coming months. If they jump to anything approaching the unvaccinated rate….this authoritarian nightmare will necessarily have to end – because even the most pro-vaccine folks within the medical establishment will have nothing left to stand on.

  • Rights Matter says:

    l am puzzled why we’re now hearing the term “vaccine waning over time” to justify booster shots. Is it really “vaccine waning” or is the immune system weakening over time? When one is vaccinated, their immune system already produced antibodies to fight the spike protein, and also memorizing it to recognise the real virus when infected. Hence it may not be the vaccine that is waning. It could be one’s immune system.

  • Don Taylor says:

    An informative and very timely article. Thank you.


Seema Marwaha


Seema Marwaha is a general internal medicine physician, educator, researcher and journalist in Toronto.

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