Skip Navigation

Get the facts about vaccines

COVID-19 vaccines are safe, effective and can protect you from severe illness or complications from the COVID-19 virus. When a large percentage of the population becomes immune, the spread of the virus will slow down and may stop.

About COVID-19 vaccines

Many potential vaccines are being investigated in Canada and worldwide for use against COVID-19. Vaccines that have been authorized by Health Canada are safe, reliable and can help protect you, your family and our community from COVID-19. It is important that we all continue to follow public health measures and take everyday actions to stop the spread of the virus.

COVID-19 vaccination:

  • will work with your immune system to help protect you from COVID-19;
  • is a safe way to help build protection against the virus;
  • will help build community protection, stopping the spread of the virus in our community; and
  • is voluntary, but strongly encouraged.

Authorized COVID-19 vaccines: Moderna, Pfizer-BioNTech and AstraZeneca

COVID-19 vaccine safety

The Pfizer-BioNTech, Moderna, and AstraZeneca COVID-19 vaccines were authorized by Health Canada after thorough and independent reviews determined that they meet stringent safety, efficacy and quality requirements. Watch this short video for an overview of the vaccine development process (YouTube video). Learn more about how vaccines are developed and approved in Canada (external link).

Pfizer-BioNTech vaccine information

The Pfizer-BioNTech COVID-19 vaccine uses a method called messenger RNA (mRNA) technology. The mRNA in the vaccine tells the body’s cells to make "spike proteins," similar to what is found on the COVID-19 virus. The immune system responds to the spike proteins by making antibodies. These new antibodies will break down the spike proteins and get rid of them. The new antibodies will protect against COVID-19 infection in the future. The mRNA is broken down by the body shortly after injection and cannot affect the body’s DNA. mRNA vaccines are not live vaccines and cannot cause infection.

Two doses of the vaccine are required for full protection, given 21 to 28 days apart. It can be given to people 16 years of age and older, including seniors. After completing the two-doses, it may take another seven days to achieve maximum protection against COVID-19. At this time, there is no information on the long-term protection with this vaccine. In trials, the vaccine was 95% effective.

There is a small chance that you may still get COVID-19 after being vaccinated. It is important to continue to follow public health measures such as physical distancing, wearing a mask, and staying home if you are sick. Health care workers and other staff must still wear personal protective equipment (PPE) even after they have been vaccinated.

Some people may experience side effects from the vaccine, but they will likely be moderate and resolve after a few days. Some of the symptoms are part of the body’s response to developing immunity to a virus.

Common side effects that have been reported in clinical trials for this vaccine include:

very common ≥10%
(more than 1 in 10 doses)

  • pain at the injection site
  • headache
  • feeling tired
  • muscle or joint pain
  • fever or chills

common 1%-10%
(1 in 100 to 1 in 10 doses)

  • redness & swelling at the injection site

uncommon 1%
(1 in 100 doses)

  • enlarged lymph nodes

In rare cases, serious allergic reactions (anaphylaxis) can occur. Allergic reactions can be treated and are usually temporary. Seek medical attention if you have trouble breathing, have hives or swelling of the mouth and throat or a high fever (over 40 degrees C or 104 degrees F). Vaccine side effects will continue to be monitored as people receive the vaccine. If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects to make sure the vaccine continues to be safe.

  • Delay getting vaccinated if you have a fever or are sick with COVID-19 symptoms.
  • Avoid trying to get pregnant for at least two months after getting both doses of the vaccine.
  • People with a bleeding disorder or who are on blood thinner medications should consult their health care provider before getting vaccinated.

Do not get this vaccine, if you:

  • are under 16 years of age;
  • are pregnant or breastfeeding;
  • have an autoimmune disorder or a weakened immune system due to illness or treatment; or
  • have an allergy to an ingredient in the vaccine or had a previous severe reaction to this vaccine.
  • have received another vaccine in the past 14 days (not a COVID-19 vaccine)

Moderna vaccine information

The Moderna COVID-19 vaccine uses a method called messenger RNA (mRNA) technology. The mRNA in the vaccine tells the body’s cells to make "spike proteins," similar to what is found on the COVID-19 virus. The immune system responds to the spike proteins by making antibodies. These new antibodies will break down the spike proteins and get rid of them. The new antibodies will protect against COVID-19 infection in the future. The mRNA is broken down by the body shortly after injection and cannot affect the body’s DNA. mRNA vaccines are not live vaccines and cannot cause infection.

Two doses of the vaccine are required for full protection, given one month apart. It can be given to people 18 years of age and older. After completing the two-doses, it may take another fourteen days to achieve maximum protection against COVID-19. In trials, the vaccine was 94% effective.

Health Canada (external link) reported that side effects that followed administration of the Moderna vaccine were mild or moderate and are common of many vaccines, including:

  • pain at the site of injection
  • body chills
  • feeling tired
  • feeling feverish

Speak with your health care professional about any serious allergies or health conditions before receiving the Moderna COVID-19 vaccine.

Vaccine side effects will continue to be monitored as people receive the vaccine. If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects to make sure the vaccine continues to be safe.

The Moderna COVID-19 vaccine is approved for use in people 18 years of age and over. Additional information will be posted as it is released from Health Canada.

AstraZeneca vaccine information

The AstraZeneca vaccine is a viral vector vaccine (external link). Unlike the Pfizer-BioNTech and Moderna vaccines which store the instructions to build spike proteins in RNA, the AstraZeneca vaccine uses DNA. The vaccine uses a harmless virus (called an adenovirus) as a delivery system. This is called a viral vector. Once the vaccine containing the viral vector enters the body, the vector virus produces the SARS-CoV-2 spike protein. Just like with the mRNA vaccines, the immune system responds to the spike proteins by making antibodies. These new antibodies will break down the spike proteins and get rid of them. The new antibodies will protect against COVID-19 infection in the future.

DNA is not as fragile as RNA. The viral vector (adenovirus) has a tough protein coat which protects the DNA inside. Therefore, the AstraZeneca vaccine does not need to be kept frozen.

Viral vector technology has been used for over ten years to produce many of the vaccines approved in Canada.

None of the COVID-19 vaccines currently approved by Health Canada use the live virus that causes COVID-19. You cannot get COVID-19 from a vaccine.

Two doses of the vaccine are required, given 4 to 12 weeks apart. It can be given to people aged 18-64. After completing the two-doses, it may take another 14 days to achieve maximum protection against COVID-19. In trials, the vaccine was 62% effective.

Health Canada reported that side effects that followed administration of the AstraZeneca vaccine were mild or moderate and are common of many vaccines (external link), including:

  • pain at the site of injection
  • body chills
  • feeling tired
  • feeling feverish

Speak with your health care professional about any serious allergies or health conditions before receiving the AstraZeneca COVID-19 vaccine.

Vaccine side effects will continue to be monitored as people receive the vaccine. If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects to make sure the vaccine continues to be safe.

The AstraZeneca COVID-19 vaccine is approved for use in people 18 years of age and over. The vaccine is not currently recommended for adults aged 65 or over due to limited information on the efficacy of this vaccine in this age group at this time.

Additional information will be posted as it is released from Health Canada.

What can I do right now?

The approval and availability of COVID-19 vaccines is an important milestone, however must not replace the public health measures that remain in place. This includes:

  • Staying home, except for essential purposes such as going to work or school, buying essential items like groceries or medicine or attending medical appointments.
  • Limiting close contact to those that live with you, and maintaining a two metre (six foot) distance from anyone outside of your household (including family and close friends) and wearing a mask.
  • Avoiding all social gatherings such as play dates, birthday parties, and dinner parties with friends or family.
COVID-19 Core Information
TOP