COVID-19 Vaccines – Questions and Answers

With the new COVID-19 vaccines being approved for use, we know you have many questions. We hope the following provides some answers. We will continue to provide updates as we learn more about the distribution and administration of the vaccines.

1. Which vaccines are coming to Canada first?

The two vaccines that Canada is receiving first are those made by Pfizer/BioNTech and Moderna. These are both mRNA vaccines. When you get an mRNA vaccine, the mRNA in these vaccines results in the production of one of the proteins (the “spike” protein) of SARS-CoV-2 (the virus that causes COVID-19).  Your immune system then makes antibodies to this protein. If you get exposed to SARS-CoV-2, these antibodies attack the virus and protect you from illness.

2. What is in these vaccines?  

These vaccines contain mRNA with encodes the spike protein from SARS-CoV-2 (the virus that causes COVID-19), lipids and cholesterol (which are needed to stabilize and protect the mRNA), and salt.  For the Pfizer/BioNTech vaccine the exact components (in addition to the mRNA) are:

  • Lipids: 
    • ALC-0315 = (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)
    • ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
    • 1,2-distearoyl-sn-glycero-3-phosphocholine
    • Cholesterol
  • Salts: basic sodium phosphate dehydrate; monobasic potassium phosphate; potassium chloride; sodium chloride;
  • Sucrose
  • Water

3. Are these vaccines safe?

The small number of components in theses vaccines minimizes the risk of both unexpected side effects and allergic reactions. To date, more than 22,000 adults have been vaccinated with the Pfizer/BioNTech vaccine. The Moderna vaccine has been given to about 15,000 adults. None of the people who have received these vaccines have developed severe side effects from the vaccine. But all vaccines and medications can be associated with allergic reactions in a small number of people, and it is possible that there are rare side effects that have not yet been identified. Public health officials around the world will be watching very carefully for any rare side effects. This is a new type of vaccine and that makes all of us more cautious about safety. However, it is important to remember that COVID-19 is a very serious threat. Getting the vaccine is safer than leaving yourself exposed to COVID-19. For further insight, please watch this video of Dr. Allison McGeer, Infection Prevention and Control Consultant.

4. Can I get COVID-19 from any of these vaccines? 

No, these vaccines make a single protein from the virus only. They do not contain live virus and cannot cause an infection.

5. How well do these vaccines protect adults against COVID-19?

In the studies so far, these vaccines prevented 95% of infections due to COVID-19. These are results for the first month after the second dose of vaccine. We do not know yet how long protection will last, but the very high protection early after vaccination suggests that substantial protection will last at a minimum for several months.

6. Is the protection different for older adults, or those with underlying illnesses?

There were older adults (over 65 years) in the studies, and protection appeared to be as good in older adults as in younger adults. However, there were relatively few adults aged over 75 years, so our confidence in the estimate of efficacy is limited. The vaccines have not yet been tested in frail older adults in long-term care. However, the very high protection for other adults likely means that protection for older, frail adults will be substantial. 

7. How long will protection from the vaccine last?

We don’t know. The best expert opinion currently, is that it will last for at least a year, although protection may decline over time. This might be a vaccine, like flu vaccine, that you have to get each year to be protected. Or, protection may last for many years.

8. Can you still get COVID-19 and spread the virus to others if you get vaccinated?

These vaccines are given as two doses, 3-4 weeks apart. Protection takes at least 2 weeks to develop, and is only partial until a week after the second dose. Thus, it is important to protect yourself until a week after your second dose of vaccine.

We know that these vaccines prevent illness in people who receive them. But we don’t know yet whether they prevent people from getting mild or asymptomatic infection which can be spread to other people. For this reason, until we know more, people who have been vaccinated still need to wear masks and maintain physical distance from others. We will be learning more over the next 3-6 months, and we hope that these recommendations will change.

9. Should people who have had COVID-19 get vaccinated?

Current public health recommendations are that people who have had COVID-19 should also get vaccinated. We still do not know the extent to which previous infection protects you against re-infection, and vaccination will likely give a boost to immunity which will protect you better for longer.

10. I have heard that there are a lot of side effects from these vaccines. Is this true?

These vaccines do create a strong immune reaction. Side effects such as pain at the injection site, fever, fatigue and muscle aches are more common in the day or two after you receive this vaccine than after vaccines such as influenza or tetanus, but less common than reactions after the inactivated shingles vaccine. These adverse effects only last a day or two, and are not serious.