COVID-19 viral vector-based vaccines

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About COVID-19 viral vector-based vaccines

Viral vector vaccines use a harmless virus (in this case, the adenovirus) as a delivery system. This vector virus is not the virus that causes COVID-19. You can't get COVID-19 from the vaccine itself.

Adenoviruses are viruses that cause the common cold. There are many different types, including those that cause colds in humans and those that infect other species. Scientists have been using these viruses for decades to deliver the instructions for proteins.

The previously authorised Janssen Jcovden (Johnson & Johnson) COVID-19 vaccine and Astrazeneca Vaxzevria COVID-19 vaccine are viral vector-based vaccines.

How viral vector-based vaccines work

Once injected into your body, the adenovirus in the vaccine produces the SARS-CoV-2 spike protein. This protein doesn't make you sick. It does its job and then goes away.

Through this process, your body can mount a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.

Viral vector-based vaccine safety

Viral vector-based technology has been used to develop:

Like all vaccines authorized for use in Canada, COVID-19 viral vector-based vaccines are held to high safety, effectiveness and quality standards. Only vaccines that meet those standards can be approved.

After we approve a vaccine, we continue to monitor it for safety and effectiveness.

We have a strong monitoring system for drug safety in Canada. Anyone who witnesses or experiences a side effect to a vaccine is strongly encouraged to report it to their health care provider.

Health care providers must report adverse events following immunization to their local public health authority. The public health authority then reports them to the Public Health Agency of Canada.

For more information on drug safety, see safety after authorization for vaccines and treatments for COVID-19.

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