COVID-19 mRNA vaccines

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About COVID-19 mRNA vaccines

Many vaccines are being studied to see if they will prevent COVID-19, and Health Canada is expediting reviews of all COVID-19 vaccine submissions. Some of the vaccine candidates that are most advanced in development are messenger RNA vaccines (called mRNA vaccines).

mRNA vaccines are a new type of vaccine. Many types of vaccines use a weakened or inactivated virus or part of a virus to trigger an immune response inside our body. However, instead of using the live virus that causes COVID-19, mRNA vaccines teach our cells how to make a protein that will trigger an immune response. Once triggered, our body then makes antibodies. These antibodies help us fight the infection if the real virus does enter our body in the future.

Researchers have been studying and working with these vaccines for quite some time. For example, they have been studied for flu, Zika, rabies and cytomegalovirus (CMV). Researchers have also used mRNA to trigger the immune system to target certain cancer cells.

mRNA vaccines can be developed faster than traditional methods because they're made in a lab using materials that are easily available. However, these technology advancements don't replace the large-scale clinical trials needed to show that the vaccine is safe and effective.

Like all vaccines, people who are vaccinated gain protection without ever having to risk the serious consequences of getting sick from being exposed to the virus. People also can't get COVID-19 from the vaccine itself.

How COVID-19 mRNA vaccines work

'RNA' stands for ribonucleic acid, which is a molecule that provides cells with instructions for making proteins. RNA vaccines contain the instructions for making the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19.

Thus, the mRNA molecule is essentially a recipe, telling the cells of the body how to make the spike protein.

COVID-19 mRNA vaccines are given by injection into the muscle of the upper arm.

After the protein piece is made, the cell breaks down the instructions and gets rid of them. The mRNA never enters the central part (nucleus) of the cell, which is where our DNA (genetic material) is found.

The cell then displays the protein piece on its surface. Our immune system recognizes that the protein doesn't belong there and begins building an immune response and making antibodies.

What we know about the safety of mRNA vaccines

Like all vaccines authorized for use in Canada, COVID-19 mRNA vaccines will be held to the same high safety, effectiveness and quality standards. Only mRNA vaccines that meet those standards will be approved.

Once a COVID-19 mRNA vaccine has been authorized for use in Canada, we will be monitoring its safety and effectiveness (how well it works) in people.

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 are required to 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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