General info on COVID-19 vaccines

LAST UPDATED: Friday, March 5, 2021

What is a vaccine?

Unlike other medications that treat or cure a disease, vaccines prevent you from getting sick in the first place. Vaccines produce immunity to a specific disease, so that you are protected against it.

In general, how do vaccines work?

Vaccines are made using killed or weakened versions of disease-causing germs. When you are vaccinated, your immune system responds as if it were exposed to the real germ and creates antibodies. Your immune system thereby learns how to react if you are exposed to the actual disease. It’s much safer to get the vaccine than the disease! 

What about the vaccines for COVID-19?

The BC Centre for Disease Control lists the vaccines approved for use in British Columbia: http://www.bccdc.ca/health-info/diseases-conditions/covid-19/covid-19-vaccine/vaccines-for-covid-19.

Two types of vaccines have been approved: mRNA, and viral vector-based vaccines. The Pfizer and Moderna COVID-19 vaccines are both examples of the mRNA variety. Messenger RNA (mRNA) teaches cells how to make a protein that will trigger an immune response without using live COVID-19 virus. As RNA is relatively fragile, these vaccines must be frozen to preserve the integrity of the material:

The AstraZeneca COVID-19 vaccine and Verity-Serum Institute of India vaccine are examples of viral vector-based vaccines. This type uses a harmless virus — in this case an adenovirus — as a delivery system. This harmless virus alerts your body to the danger of COVID-19 and trains your immune system to recognize and fight it.

How are vaccines approved for use in Canada?

Vaccines are first tested on animals, and then human testing is done in three phases. Phase one tests the vaccine on up to 100 healthy adults. Phase two usually involves up to 500 healthy adults. Phase three involves from thousands to tens of thousands of people. Safety is analyzed in each phase. If a vaccine successfully passes all three phases, and proves effective to prevent the disease, the testing data is submitted to Health Canada — who checks the evidence of safety, as well as manufacturing standards.

Will the vaccine make me sick?

You cannot get COVID-19 from the vaccines. Common reactions to vaccine injections include soreness, redness or swelling. Other reactions could include tiredness, headache, fever, chills, muscle or joint soreness, nausea and vomiting. Such reactions are mild and generally last one to two days. No serious side effects of the vaccines were found in the clinical trials

About one in one million people can have an allergic reaction called anaphylaxis. For this reason, you must stay in the clinic for 15 minutes after getting the vaccine so that health care providers can treat you, if this condition arises.

Who should not get the vaccine?

People with a serious allergy to polyethylene glycol or those who have had a life-threatening reaction to a previous dose of the COVID-19 vaccine (or any part of the vaccine) should not get mRNA vaccines. Speak to your health care provider if you have additional concerns.

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