The Second COVID-19 Vaccine Dose: Why We All Need To Get It, and What To Expect



VaxCh​amp Steven Raphael (Nlaka'pamux) recieves a COVID-19 vaccine

A message from Dr. Helena Swinkels, Office of the Chief Medical Officer; and Marion Guenther, Clinical Nurse Specialist for Immunizations, Office of the Chief Nursing Officer.


As the FNHA prepares to start second-dose COVID-19 vaccine clinics in First Nations communities around BC, some people may be wondering why we need to get a second dose. After all, the first dose of the vaccine does provide a high level of protection.

Here's why we all need to get our second dose:

  • The two doses make up what's known as one “primary series" that will provide the strongest — and longest — possible protection, including against new, more vaccine-resistant variants that are circulating the globe.
  • Most of the COVID-19 vaccines in Canada require two doses as part of the primary series. These include Pfizer, Moderna and AstraZeneca. (The Janssen vaccine reaches maximum protection after just one dose.)

Scientists are still studying how long the primary series of COVID-19 vaccines remain effective in preventing COVID-19 and whether we will need “booster" doses later to keep this protection high. They are also studying whether additional shots will be needed to provide better protection against emerging variants, similar to getting an influenza shot each year.

We do know for certain that protection is higher after a second dose for the Pfizer, Moderna and AstraZeneca vaccines: A study from the Centers for Disease Control and Prevention (CDC) found that a single dose of Pfizer or Moderna vaccine was 80 per cent effective at preventing the spread of COVID-19. That protection rose to 90 per cent after the second dose. This is a significant increase in protection when dealing with a potentially deadly disease.

Side effects are similar to dose one, with possible short-term symptoms of a sore arm where you had the injection, fever, headache and fatigue. These mild to moderate side effects should disappear within a few days after vaccination.

These side effects are one sign your immune system is working. But don't worry if you feel no side effects at all — your immune system is still working hard to protect you from COVID-19!

Currently, the province of BC is making it a priority to get everyone their first dose of COVID-19 vaccine and ensuring that those who are due for their second dose get these as soon as supply is available. The FNHA continues to work hard with First Nations communities and provincial and regional partners to make vaccines accessible to everyone who wants one.

For information on getting your second dose, check here​.

Remember, no vaccines provide 100 per cent protection. While vaccines greatly reduce the chance of hospitalization and death from COVID-19, you can still pass on the infection and you can still get sick—even after receiving a vaccine.

As well, there are currently no COVID-19 vaccines available for children in Canada. These are some of the reasons we need to continue practising recommended public health measures—such as physical distancing, wearing face masks, and washing our hands frequently until more of us have had the chance to be vaccinated.

Do you have other questions about COVID-19 vaccines? Visit our COVID-19 vaccine FAQs page, which provides up-to-ate information and links to other resources.

Related resources:

COVID-19 Vaccine Anxieties and​ Apprehensions (video)
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