COVID-19 Infectious Diseases

Why bother with a booster?

British Columbians with two doses of vaccine are considered fully vaccinated. This means one can expect good protection against serious illness from COVID-19, compliance with workplace vaccine mandates, and access to restaurants, concerts, sporting events, gyms and movie theatres via the BC Vaccine Card.

And thanks to the Omicron variant and its ability to evade antibodies, we’ve also just come off a massive wave of new infections among fully vaccinated people. So is getting a booster worth it? Will it even make a difference?


Booster is key for deeper defence 

To date, much of vaccine research has focused on the body’s antibody response after receiving the vaccine – proteins in the blood that form an early line of defence in preventing the virus from infecting cells.

But new research suggests that a booster of vaccine is needed to prompt the body to build a deeper level defense through our immune cells. Four weeks after receiving a booster, your body’s B cells and T cells are able to mount a stronger, longer lasting immune response than what our body initially produces from the first two doses through antibody molecules. Perhaps most importantly, these immune cells have shown an ability to recognize and neutralize variants of the SARS Co-V2 virus, such as Omicron and Delta.

This is why booster doses appear to be particularly effective in maintaining one’s level of immunity over time.

The BC Ministry of Health says that those who have received their booster are 60 – 70% less likely to report COVID-19 symptoms than those who are unvaccinated, and are 80% less likely to require hospital care due to a COVID-19 infection.


But I’ve already had COVID, wouldn’t that count as my booster?

You should still get a booster dose even if you’ve already had COVID-19.

The immune response generated “naturally” (or from having recovered from a previous COVID-19 illness) can vary greatly from person to person and from infection to infection. Factors such as age, severity of illness and type of variant can all greatly impact the amount and longevity of natural immunity gained through a previous infection.

Research has shown that vaccination provides the most consistently strong immune response, which is why a booster dose is recommended for everyone, regardless of the number of previous infections they have had.


Does the brand of the booster matter?

Pfizer and Moderna are currently the two boosters available for British Columbians, and both are very effective mRNA vaccines. There is no need for your booster to be the same brand as your first and second doses. Getting an mRNA vaccine booster is highly effective and safe, even if you received AstraZeneca or Janssen vaccine for a previous dose.

The ingredients in the vaccines used for booster doses are the same as the ingredients in the vaccines for the first and second doses.


What is the difference between a booster dose and a three-dose series?

A booster dose is an additional does added onto your primary series of vaccine (a primary vaccine series is two doses for most people) It helps maintain and lengthen your protection against severe outcomes of COVID-19.

A three-dose series is for people aged 5 and up who are moderately to severely immunocompromised. In this case, complete vaccination series is a three dose series so the third dose is actually part of their primary vaccine series rather than a booster. These individuals may not develop a strong enough immune response with only two doses of vaccine, therefore they require three doses of vaccine to achieve the level of protection that most people get with two doses.


How do I get my booster after I have completed my primary vaccine series?

The first step is to make sure you’re registered in the Get Vaccinated system. Everyone aged 12 and older who already received dose 1 and 2 can get a booster dose, 6 months after their initial series. Those who received the Janssen vaccine can get a booster 2 months after their vaccine. Pregnant people can get a booster dose 2 months (8 weeks) after their second dose.

If you are sick or have symptoms of COVID-19, wait until you feel better to get your booster dose.

You must be invited to book a booster dose appointment. You can’t drop-in at a clinic or call a pharmacy to get a booster.

Get your booster dose!