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15 answers to key questions about COVID-19 vaccines

By January 20, 2021 No Comments

With the first doses being administrated across the country, the Pfizer-BioNTech COVID-19 vaccine has raised many questions around the world as well as here in Canada. Recently, the Moderna COVID-19 vaccine (mRNA-1273) has also been approved by Health Canada and more questions are emerging related to this other vaccine.

Both Pfizer-BioNTech and Moderna COVID-19 vaccines are used to prevent COVID-19 which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Even though both are now available, many questions remain unanswered about the Pfizer-BioNTech and Moderna COVID-19 vaccines. The two most important unanswered questions are

  • How long does immunity last with COVID-19 vaccines?
  • Do the vaccines prevent the spread of coronavirus?

With time and further research on vaccinated individuals, we will have the answers to these two key questions.

Despite the fact that many people are being vaccinated, it is very important to continue to follow public health guidelines and COVID-19 precautions: wearing masks, practicing proper hand hygiene, physical distancing, and avoiding gatherings.  We will need to continue with these key measures until enough of the population has become immune, so that the virus can no longer spread effectively.

Here are answers to some of the most common questions about these two vaccines.


  1. What are the ingredients in the COVID-19 vaccine?
  • Pfizer-BioNTech COVID-19:

Medicinal ingredient: mRNA

 Non-medicinal ingredients: 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, dibasic sodium phosphate dihydrate, monobasic potassium phosphate, potassium chloride, sodium chloride, sucrose, and water for injection

  • Moderna COVID-19:

Medicinal ingredient: mRNA

Non-medicinal ingredients: 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), acetic acid, cholesterol, lipid SM-102, polyethylene glycol (PEG) 2000 DMG, sodium acetate, sucrose, tromethamine, tromethamine, hydrochloride, and water for injection


  1. How does each of the vaccines work?

Both Moderna’s and Pfizer’s vaccines use messenger RNA (mRNA). After the mRNA is injected into the body, it enters our cells. It prompts them to produce a protein that is the same as a portion of the spike protein from the outside of the coronavirus. The presence of this protein is what activates the immune response, and our body starts producing antibodies to it. It is important to understand that it is the exact same process that occurs with natural infection:  the virus uses our own cells to make copies of itself that further infect us. The mRNA in a vaccine only makes a very small portion of the virus that cannot harm us, instead of the whole thing.


  1. What is the temperature needed to store the vaccine?
  • Pfizer-BioNTech COVID-19: -70°C
  • Moderna COVID-19: It can be stored in a freezer, between -25°C and -15°C.


  1. Can mRNA vaccines alter your DNA?

mRNA never enters the nucleus of the cell, which is where our DNA is kept, and does not affect or interact with a person’s DNA. It is also degraded quickly over the course of hours and is completely gone in approximately 48 hours.


  1. How many doses of the vaccine are needed?
  • Pfizer/BioNTech COVID-19: must be delivered in two doses, 21 days apart.
  • Moderna COVID-19: must be delivered in two doses, 28 days apart.


  1. Is the vaccine safe?
  • Pfizer-BioNTech COVID-19: The vaccine is safe, it has been tested in large clinical trials to ensure it has met safety standards. It has been licensed and approved for use by Health Canada.
  • Moderna COVID-19: The vaccine is safe. Health Canada authorized the vaccine after an independent and thorough scientific review of the clinical trial data. The data showed the efficacy of the Moderna COVID-19 vaccine as well as its safety.


  1. Are there any side effects to the vaccine?
  • Pfizer-BioNTech COVID-19: Side effects of the vaccine include fatigue, pain at the injection site, body chills, headache, and muscle pain.
  • Moderna COVID-19: The side effects may include soreness at the injection site, body chills, fatigue, muscle pain, and feeling feverish.


  1. Does the vaccine cause a severe allergic reaction?
  • Pfizer-BioNTech COVID-19: In rare occasions, serious allergic reactions (anaphylaxis) can occur.

If you have experienced a serious allergic reaction to another vaccine, medication or food, you should talk to your health professional before you receive the vaccine.

If you know you have allergies to any of the ingredients in the Pfizer-BioNTech COVID-19 vaccine, you should not receive it.

  • Moderna COVID-19: Some people may experience severe allergic reactions (anaphylaxis) after getting the vaccine.

If you have experienced a serious allergic reaction to another vaccine, medication or food, you should talk to your health professional before you receive the vaccine.

Health Canada warned that people should not take the vaccine if they are allergic to any of the ingredients in the Moderna vaccine.


  1. Which groups are on the priority list to receive the vaccine in the first few months?

According to the National Advisory Committee on Immunization (NACI), the following populations should be prioritized for early COVID-19 vaccination:

  • Residents and staff of shared living settings that provide care for seniors.
  • Adults 70 years of age and older, with order of priority:
    • beginning with adults 80 years of age and older
    • decreasing the age limit by 5-year increments to age 70 years as supply becomes available
  • Health care workers who have direct contact with patients, including:
    • those who work in health care settings
    • personal support workers
  • Adults in Indigenous communities.


  1. Should I get the vaccine if I am pregnant or breastfeeding?

There are no data on the safety of COVID-19 vaccines in pregnant or in breastfeeding women. The National Advisory Committee on Immunization recommended more testing is needed before COVID-19 vaccines should routinely be offered to pregnant or breastfeeding women.

The decision to vaccinate if you are pregnant or breast feeding should be a decision made between you and your doctor knowing your specific risk profile


  1. Is there an age requirement to receive the vaccine?
  • Pfizer-BioNTech COVID-19: Health Canada will let only people age 16 and older get the vaccine. There is a lack of data on how Pfizer’s injection affects individuals under 16 years of age.
  • Moderna COVID-19: Health Canada will let only people age 18 and older get the vaccine.


  1. Is it mandatory to get the vaccine in Canada?

COVID-19 vaccine is made available to Canadians. It is not mandatory to get it.


  1. Should people who still have COVID-19 get the vaccine?

No. Individuals with COVID-19 should stay isolated until they recover and get vaccinated later.


  1. There are new strains of COVID-19. Will the vaccine work against them?

The World Health Organization has stated that the new strains of coronavirus identified in the United Kingdom and in South Africa appear to be more infectious but that experts have informed the organization that at the present time they do not believe that the available COVID-19 vaccines will not offer protection against them.


  1. What is the effectiveness rate of the vaccine?
  • Pfizer-BioNTech COVID-19: 95%
  • Moderna COVID-19: 94.1%


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*Links to the Pfizer Inc. corporate website are included for reference only and further reading regarding the COVID-19 vaccine. Novus Health is in no way affiliated with Pfizer Inc.