COVID-19 Vaccine Frequently Asked Questions
Below you will find answers to frequently asked questions about COVID-19 vaccines. This list will be updated as information becomes available and as additional vaccines are approved by Health Canada.
About the vaccines
How do COVID-19 mRNA vaccines work?
Vaccines teach your immune system how to protect you from diseases. It's much safer for your immune system to learn this through vaccination than by catching the diseases and attempting to treat them.
mRNA technology has been studied for more than 10 years, most often in cancer research and treatment as well as in the development of new vaccines against such infections as pandemic influenza and rabies. Shortly after COVID-19 was identified scientists were able to map the genes that make up the COVID-19 virus. Once the structure of the genes was known, especially of the spike protein that allows that virus to fuse with and enter our cells, scientists were able to quickly create the vaccine and start the clinical trials that have resulted in the Pfizer and Moderna vaccines that have been approved for use by Health Canada.
Below is an explanation of how the approved Pfizer-BioNtech and Moderna mRNA COVID-19 vaccines work with your body’s immune response to fight off the COVID-19 virus.
COVID-19 mRNA vaccines tell your body to make "spike proteins" (these cover the outside of the virus and allow it to attach to and enter our cells) specific to virus that causes COVID-19.
- Your immune system responds to spike proteins by making antibodies that bind to and block the spike protein on the virus’s surface. This is important for protection from disease because the spike protein is what attaches to human cells, allowing the virus to enter. Blocking this entrance prevents infection.
- Your new antibodies will attack the spike proteins
- Your new antibodies and immune cells will protect you from illness if you are exposed to COVID-19 virus in the future by remembering how to attack the spike protein
Will the vaccines interact with your DNA in any way?
mRNA is a short-form of ‘messenger RNA’ – meaning that it’s a messenger.
DNA is contained in the nucleus of our cells and mRNA cannot get into the nucleus or interact with our DNA.
mRNA cannot change your DNA, it is a part of our genetic material that gives instructions to the body, like a recipe. It simply delivers a message.
- For COVID-19, the mRNA vaccine tells the body to make a harmless “spike protein”. This spike protein is found on the outside of the COVID-19 virus (but is not the virus itself). Our immune system recognizes the spike protein as something that shouldn’t be there and quickly works to attack it by building antibodies and immune cells that will attack the COVID virus if you are exposed in the future.
Human cells break down and get rid of the mRNA soon after they have finished using the instructions. mRNA does not interact with the part of our cells that holds our DNA and cannot be ‘swapped out’ or change the DNA sequence (there only function is to deliver the message of the spike protein to the cell).
Can I get other vaccines at the same time or after my COVID-19 vaccine?
COVID-19 vaccines should not be given at the same time as other vaccines:
- If possible, wait for at least 14 days after receiving another vaccine before getting the mRNA COVID-19 vaccine. It is not a safety concern if it has been less than 14 days. Separating vaccines by 14 days can help us determine which vaccine may have caused a side effect if one happens.
- Wait at least 28 days after finishing the two-dose vaccine series of a mRNA COVID-19 vaccine before getting another vaccine (except in the case where another vaccine is required because you have been exposed to another vaccine-preventable disease).
Please talk to your immunization provider if you have more questions.
Will I have to get more than one dose of the COVID-19 vaccine?
For the currently approved Pfizer-BioNtech COVID-19 vaccine, two doses of the vaccine are required for better protection, given 21 days apart. It can be given to people 16 years of age and older, including seniors. After completing the two-doses, it may take another seven days to achieve maximum protection against COVID-19. The Pfizer-BioNtech clinical studies included over 43,000 participants and was 95% effective in preventing COVID-19 beginning 2 weeks after the second dose. In clinical trials the vaccine showed robust antibody response in youth ages 12 to 17.
Two doses are also required for the Moderna vaccine. Based on studies in about 30,000 participants, the Moderna COVID-19 vaccine was 94.1% effective in preventing COVID-19 beginning 2 weeks after the second dose.
If I get the vaccine, how long will it protect me?
At this time, the duration of protection from the vaccines remains unknown, and further doses may be necessary. The duration of immunity from contracting the infection also remains unknown. Ongoing monitoring of the COVID-19 vaccines and their effects on long-term immunity continues.
Can I get COVID-19 after being vaccinated?
COVID-19 vaccines are very effective at reducing the risk of severe illness, hospitalization and death and limiting the spread of the virus in a community, but vaccines do not remove all risk of acquiring a COVID-19 infection. Some COVID-19 infections may occur among fully-vaccinated individuals, referred to as ‘breakthrough infection’.
Vaccines work by teaching our immune systems to fight off the virus so that we don’t become severely ill when we come into contact with it, but they cannot prevent us from coming into contact with the virus altogether. The protection a vaccine offers you also depends on the percentage of people around you who are also fully vaccinated (community immunity), other public health measures you follow, and how much of the virus is circulating. That is why everyone should continue to follow public health guidance and advice to protect community members from the transmission of COVID-19. The occurrence of breakthrough infections happens with all vaccines, not just with COVID-19 vaccines.
Your risk of getting COVID-19 and becoming seriously ill or dying is significantly higher if you are not vaccinated, than if you are fully vaccinated. We also know that two doses of a COVID-19 vaccine are more effective against the Delta variant.
Remember that it typically takes two weeks after vaccination for the body to build protection (immunity) against the virus that causes COVID-19 and to reach a level to protect us from severe illness. That means it is possible a person could still get COVID-19 before or just after getting a vaccine. For these reasons, it is important to continue following public health measures even after being vaccinated. This includes staying home if you have any symptoms of COVID-19, wearing a mask, keeping a distance of 2 metres from others, and washing your hands often.
Public Health Ontario reported the following data for COVID-19 infections as of June 26, 2021:
- 95.7% of COVID-19 cases reported in Ontario since COVID-19 vaccinations began in December 2020 have been in unvaccinated individuals.
- Infections amongst fully vaccinated Ontarians account for 0.4% of reported COVID-19 cases since COVID-19 vaccinations began in December 2020.
- Infections amongst partially vaccinated Ontarians account for 3.9% of reported COVID-19 cases since COVID-19 vaccinations began in December 2020.
- Out of the 16,896 cases reported in Hamilton since December 2020, only 0.3% have been in fully vaccinated individuals and 4.1% in partially vaccinated individuals
Will I still have to follow other COVID-19 measures once I get the vaccine?
Yes, it is essential that you still act to prevent the spread of COVID-19 in the community, so it is important to follow public health measures until we have reached a level of community vaccination that suggests widespread immunity. This includes staying home if you have any symptoms of COVID-19, wearing a mask, keeping a distance of at least 2 metres from others and washing your hands often.
Will these COVID-19 vaccines work on new strains of the disease?
Data about the efficacy of authorized vaccines against variants is evolving. The National Advisory Committee on Immunization in Canada will continue to monitor the evidence and update recommendations as needed.
If I received the COVID-19 vaccine and need a COVID-19 test a few days later for travel, will I test positive for COVID-19?
No, getting a COVID-19 vaccine will not give you a positive result on a COVID-19 test that is needed for travel. It is possible to test positive on an antibody test. However, these are blood tests and are not commonly used in Ontario.
Can I mix vaccine brands for my first and second dose?
The National Advisory Committee on Immunization (NACI) has confirmed that a mixed vaccine schedule (receiving both Moderna and Pfizer) can be completed safely and is effective. All vaccines provide strong protection against COVID-19 and its variants. To ensure maximum protection against COVID-19 and the Delta variant, people are encouraged to get vaccinated as soon as they can and to receive their second dose within the recommended interval.
Making a decision about getting vaccinated
I’ve already had COVID-19/have COVID-19 antibodies. Do I need the vaccine?
Yes. You should still get vaccinated. At this time, we do not know the length of immune response in those who’ve had a COVID-19 infection. When you get the COVID-19 vaccine, it can help protect you against re-infection and may prevent you from transmitting the virus to others.
If I have been infected with COVID-19, how long should I wait before getting a COVID-19 vaccine?
If you have been infected with COVID-19, you are able to get a COVID-19 vaccine. You should wait to get the vaccine until after the infection (symptoms) is resolved and you are told by Public Health that you no longer need to self-isolate. It is important to wait the full isolation period so that you do not expose other people to the virus.
If you had COVID-19 you should get the vaccine once you have recovered. This is because you may not be immune to the virus that causes COVID-19 and you could get infected again.
If there are effective treatments for COVID-19, why do we need a vaccine?
It is always better to prevent an illness, rather than get it and treat it. A vaccine can help stop you getting ill, lessen the impact of COVID-19 and slow it spreading in the community. There is some evidence to show that even a mild case of COVID-19 can be harmful to a person’s respiratory and cardiac system.
How do I decide if this is right for me and my family?
Get informed and make your decisions based on evidence and what makes sense for your family. The Pfizer-BioNtech COVID-19 vaccine is currently approved for people over 12 years of age and the Moderna vaccine is approved for people 18 years of age and older.
Vaccination is a personal choice that is important for prevention of serious disease. Public Health recommends that everyone who is eligible gets the vaccine once it is available, but recognize that the choice is not always as easy as following this advice. Take the time to read and understand the vaccine information on this page and from other reliable sources. Follow-up by asking questions and reaching out to trusted medical experts like your family doctor, nurse practitioner, or health care provider.
How can I talk to people about getting vaccinated?
Here are some tips for talking to others about vaccines:
- Be positive and non-judgmental
- Encourage people to ask questions about vaccines
- Reassure people that it’s normal to have questions or concerns about vaccines
- Be compassionate and empathetic whenever people share their stories, questions and concerns. Show them you understand their feelings about vaccines
- Encourage people to use credible sources of information (e.g. health care provider, government website)
How many people have been vaccinated in Hamilton?
Check the vaccine distribution page to find out how many people have been vaccinated in Hamilton
Will the COVID-19 vaccines be mandatory in the future?
COVID-19 vaccination is not currently mandatory. Some workplaces may require you to get the vaccine as part of their health and safety requirements, just like other vaccines.The Canadian government has stated it is looking at requirements around vaccination for international travel in the future.
Getting a vaccine
Safety and effectiveness of the COVID-19 vaccine
To date, there are 4 COVID-19 vaccines approved for use in Canada by Health Canada.
- Pfizer-BioNTech - approved December 9, 2020
- Moderna – approved December 23, 2020
- AstraZeneca – approved February 26, 2021
- Janssen/Johnson & Johnson – approved March 5, 2021
Other vaccines are currently at various stages of regulatory approval by Health Canada.
Vaccine development and approval
Development and approval of the vaccine feels rushed. Can we trust that the COVID vaccine is safe?
There is a misconception that vaccine research must take a long time. While creating a new vaccine can sometimes take years, the progress on COVID-19 vaccines is happening quickly for many reasons, including:
- advances in science and technology
- international collaboration among scientists, health professionals, researchers, industry and governments
- increased dedicated funding
For any vaccine to reach the general public it must pass careful evaluation by Health Canada and will have to pass safety standards. What made this vaccine approval feel rushed in comparison to other vaccines is the result of a highly focused and shared effort by researchers and scientists in every part of the world - combined new processes for review and evaluation of clinical trial data in addition to increased funding for vaccine research.
No corners were cut while creating the vaccines. One minor change to the usual process was put in place: clinical trials were run at the same time as the vaccines were being made/manufactured; that way, vaccines could be shipped out to different countries as soon as the vaccines were approved by the different countries’ health authorities.
Who participated in the clinical trials?
The different clinical trials included over 70,000 people. 43,448 people were included in the Pfizer trials; 30,000 people were included in the Moderna vaccine trials.
Between 35-40% of the participants were Black or African American, Latinx and Hispanic in both vaccine clinical trials (Pfizer BioNtech and Moderna).
Source: Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. Polack et al. The New England Journal of Medicine
23,848 people participated in the clinical trials for AstraZeneca. Approximately 10% of participants in the clinical trials for AstraZeneca identified as Black.
43, 783 people from across the United States, Latin America, and South Africa participated in the clinical trials for the Janssen/J&J vaccine. Clinical trials for the Janssen/J&J vaccine included participants from across multiple age ranges and racial groups. Source: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html
Clinical trials make efforts to include a wide range of people to make sure that the evidence would support a wide range of people benefitting from vaccination. Often vaccine clinical trials start with healthier people and, if successful, go on to other at-risk populations, for example, people with chronic illnesses.
Clinical trials in children older than 12 years old have begun. Canadian guidelines for COVID-19 vaccines in people who are pregnant, breastfeeding or are immunocompromised can be found here.
The vaccine trials included people over the age of 65 and the vaccine was found to be safe and effective in this age group.
Did the vaccine trials include Black, Indigenous, or Latinx people?
Yes. Clinical trials included over 70,000 volunteers. Between 35-40% of the participants were Black or African American, Latinx and Hispanic in both vaccine clinical trials (Pfizer BioNtech and Moderna).
Several hundred people in the trials self-identified as American Indians or Alaska Natives, but this number was too small to be certain how effective the vaccine was in preventing COVID infections in Indigenous people.
Approximately 10% of participants in the clinical trials for AstraZeneca identified as Black.
Clinical trials for the Janssen/J&J vaccine included the following breakdown of participants: 45.3% Hispanic or Latino, 19.4% Black or African American, 9.5% American Indian or Alaska Native, and 3.3% Asian. 33.5% were aged 60 years and older. Source: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html
How effective are the vaccines again severe disease and hospitalization?
All of the approved vaccines have a high efficacy rate against severe disease. In the clinical trials, efficacy against severe disease was shown to be:
- Pfizer: 75-100% (after dose 2)
- Moderna: 100% (14 days after dose 2)
- AstraZeneca: 100% (after dose 2)
Vaccine efficacy is the percentage reduction in disease incidence in a vaccinated group compared to an unvaccinated group under ideal (i.e., clinical trial) conditions (source: WHO). A vaccine with an efficacy of 90% in a trial, for instance, means there was a 90% reduction in cases of disease in the vaccinated group compared to the unvaccinated (or placebo) group.
What is in the COVID-19 vaccine?
COVID-19 vaccines do not contain eggs, gelatin (pork), gluten, latex, preservatives, antibiotics or aluminum.
The ingredients in the Pfizer BioNtech COVID-19 vaccine authorized for use in Canada are:
- Medicinal ingredient
- 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
- dibasic sodium phosphate dihydrate
- monobasic potassium phosphate
- potassium chloride
- sodium chloride
- water for injection
The ingredients in the Moderna COVID-19 vaccine authorized for use in Canada are:
- Medicinal ingredient
- Non-medicinal ingredients
- 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)
- acetic acid
- lipid SM-102
- polyethylene glycol (PEG) 2000 DMG
- sodium acetate
- tromethamine hydrochloride
- water for injection
Note: Polyethylene glycol (PEG) is in both mRNA vaccines. It can also be found in laxatives, makeup, skin care products, personal lubricants, toothpastes, and some contact lenses. It is also in cough syrup, and in some food and drinks.
Do COVID-19 vaccines contain animal by-products
There are no pork-derived materials, the fatty layers that protect the mRNA are plant-based or synthetic, there are no blood fractions or fetal cells products in the vaccines.
Source: South Asian COVID Task Force Canada.
Does the vaccine contain a microchip and have the ability to track or gather personal information into a database?
No, the vaccine does not contain a “microchip”. This concern started after comments made by Bill Gates from The Gates Foundation about a digital certificate of vaccine records. A digital certificate is not something that can be contained with in a vaccine and is not a microchip. The technology referred to by Gates has nothing to do with the development, testing or distribution of the COVID-19 vaccine.
Vaccine side effects
What are the potential side effects of the vaccine?
After being vaccinated, it's common to have mild side effects. This is the body's natural response, as it's working hard to build immunity against the disease. This is known as the inflammatory response or reaction. Side effects will likely be moderate and resolve after a few days.
Common side effects that have been reported in the clinical trials for the Pfizer BioNtech COVID-19 vaccine include:
|very common ≥10%
(more than 1 in 10 doses)
(1 in 100 to 1 in 10 doses)
(1 in 100 doses)
These effects are more likely after the second dose of vaccine and will typically go away in a day or two. These effects are a normal part of your body’s response to most vaccines – it is a sign that your body’s immune system is learning how to recognize and fight the virus that causes COVID-19. Some people may experience more serious allergic reactions to the vaccine, but these are unlikely and tracked closely by Health Canada as part of on-going monitoring of vaccine safety.
If you have questions about these effects, reach out your health care provider (doctor, nurse or pharmacist).
In rare cases, serious allergic reactions (anaphylaxis) can occur. Allergic reactions can be treated and are usually temporary. Seek medical attention if you have trouble breathing, have hives or swelling of the face and throat. Vaccine side effects will continue to be monitored as people receive the vaccine. If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects.
Visit Health Canada for more information on the side effects of the Pfizer BioNTech COVID-19.
Common side effects that have been reported in the clinical trials for the Moderna COVID-19 vaccine include mild to moderate: pain at the site of injection, body chills, feeling tired and feeling feverish.
Visit Health Canada for more information on the potential side effects of the Moderna COVID-19 vaccine.
Have COVID-19 vaccines been linked to infertility or miscarriage?
There is no science-based reason why a COVID-19 vaccine would lead to infertility or miscarriage.
The best evidence comes from women who got sick with COVID-19 while pregnant. Studies show that pregnant women are more likely to be hospitalized when they have COVID-19, but they are not more likely to miscarry.
Could the vaccine side effects be worse than getting COVID-19?
Some people’s experience of COVID-19 may be mild, but it can also cause some people to become very sick or even lead to death. There is some research to show that even a mild case of COVID-19 can be harmful to a person’s lungs (which makes breathing hard) and to their heart and cardiovascular system (your heart and how blood flows through your body). There is also a worrisome number of people experiencing on-going and at times debilitating symptoms for weeks or months after their initial COVID-19 infection (sometimes called ‘long COVID’).
Your risk of dying from COVID-19 increases as you age, is you are male or if you have chronic health conditions such as heart or lung disease or diabetes.
Is there long-term evidence on potential harms?
As part of the vaccine safety program in Canada, ongoing, careful monitoring of the COVID-19 vaccines will continue. Very careful tracking of those vaccinated will be carried out by the healthcare and public health systems at local, provincial and national levels. There is also longer-term follow-up of those who were vaccinated as part of the clinical trials. Health Canada posts weekly reports on vaccine safety.
I have already received the AstraZeneca vaccine for my first dose. What should I get for my second dose?
mRNA vaccines are available for second doses for those who received AstraZeneca first dose. It is safe and effective to mix vaccines.
Do mRNA vaccine cause pericarditis and/or myocarditis?
Rare cases of myocarditis and pericarditis have been reported after mRNA COVID-19 vaccination (Pfizer-BioNTech and Moderna) in Canada and internationally, including in the United States and Israel. Myocarditis is inflammation of the heart muscle, and pericarditis is inflammation of the lining outside the heart. In both cases, the body’s immune system is causing inflammation in response to an infection or some other trigger. Symptoms can include chest pain, shortness of breath, or palpitations. Available information indicates that these cases have occurred: mainly in adolescents and young adults, more often in males than females, more commonly after the second dose, and typically within several days after vaccination. Most cases appear to be mild and respond well to conservative treatment (e.g. non-steroidal anti-inflammatory drugs) and rest.
Based on the reports received, Health Canada and PHAC are not yet seeing higher rates of myocarditis/pericarditis than would normally be expected in the general population. To date, no jurisdiction has suspended the use of COVID-19 mRNA vaccines, or changed their vaccine guidance. All countries who are using mRNA vaccines in young adults and adolescents are continuing to recommend their use, but are following the emerging evidence on this topic very closely as further information is collected.
The benefits of COVID-19 vaccines continue to outweigh their potential risks, as scientific evidence shows that they reduce deaths and hospitalizations due to COVID-19. The Government of Canada encourages people to get vaccinated and to complete their vaccine series as soon as they are eligible.
Can I get the COVID-19 virus from the vaccine?
The vaccines will not give you a COVID-19 infection. None of the approved vaccines contains a live version of the COVID-19 virus. Instead all the vaccines either deliver, or cause our bodies to make, harmless spike proteins only found on the surface of the COVID-19 virus and teaches your body how to spot and respond to this protein so when the real virus comes along, the body can fight it off.
How do I report an adverse reaction to the vaccine?
Severe reactions are uncommon but if you need immediate medical assistance, call 911.
Signs of serious allergic reactions may include:
- difficulty breathing
- swelling of face, throat or tongue
- hives (bumps on the skin that are itchy)
If these occur, a doctor should report them to Hamilton Public Health Services.
Other uncommon adverse reactions that you should contact your health care provider about so they can report these to Hamilton Public Health Services include:
- swelling of arm that spreads to the next joint (elbow) or lasts 4 days or more
- pain that lasts 4 days or more
- fainting that causes injury
- swelling of the face or mouth
- very pale colour and serious drowsiness
- high fever (over 40°C)
- convulsions or seizures
- other serious symptoms (e.g., “pins and needles” or numbness lasting for over 24 hours).
- Discuss any of the uncommon reactions with your family doctor. If you don’t have a family doctor, a walk-in clinic might be preferred. A doctor can diagnose these uncommon reactions and report them to public health. If you do not have access to a doctor, please call Hamilton Public Health Services Vaccine program at 905-546-2424 ext. 7556 to report symptoms.
Read more about adverse effects (PDF, 135 KB)
Considerations for those with health conditions
I have a health condition. How can I be sure the vaccine is safe?
Some individuals may consider themselves more vulnerable to side effects or negative effects from the vaccine. Speak with your doctor or health care provider about any questions or concerns you have about COVID-19 vaccines.
Can people who have autoimmune disorders or are immunocompromised get the vaccines?
There is limited information on the use of COVID-19 vaccines in people who have autoimmune disorders and people who are immunocompromised. It is possible that the vaccine will have decreased effectiveness due to immunosuppression.
Immunosuppressed individuals in the authorized age group (12+ for Pfizer BioNTech vaccine; 18+ for Moderna vaccine) with autoimmune conditions, immunodeficiency conditions, or those immunosuppressed due to disease or treatment may choose to receive the vaccine after speaking to a health care provider about the risks, benefits, and lack of specific research data.
Individuals who are immunosuppressed due to disease or treatment or with an autoimmune condition, should consult their treating provider to discuss getting the COVID-19 vaccines.
For additional information on rheumatology, consult the Canadian Rheumatology Association statement on COVID-19 vaccination.
For additional information on inflammatory bowel disease, consult the Canadian Association of Gastroenterology statement on COVID-19 vaccination.
Can people who have allergies get the vaccines?
Individuals who have ever had a severe allergic reaction (i.e. anaphylaxis) to a previous dose of an mRNA vaccine or to any of its components or its container, should not get either mRNA COVID-19 vaccine.
Individuals who have a suspected hypersensitivity or have had an immediate allergic reaction to:
- a previous dose of an mRNA COVID-19 vaccine
- any of components of the mRNA COVID-19 vaccine (including polyethylene glycol [PEG])
should not get mRNA COVID-19 vaccine unless they have been evaluated by an allergist-immunologist and it is determined that the person can safely receive the vaccine.
Individuals who have had a severe allergic reaction (i.e., anaphylaxis) to other vaccines or injectable therapies, must be evaluated by an allergist-immunologist before getting the COVID-19 vaccines so that a thorough risk/benefit discussion can take place and vaccination safety plan developed.
Individuals who have had an immediate allergic reaction to other vaccines or injectable therapies must discuss the risks and benefits of vaccination with their treating health care provider. In some cases, your treating health care provider may consult with an allergist-immunologist.
Individuals with a history of severe allergic reactions (i.e. anaphylaxis) not related to vaccines or injectable medications (for example, allergies to food, pet, venom, environmental, or latex, etc.) may choose to have the COVID-19 vaccines. The vaccination clinic will monitor you for 30 minutes following vaccination. With an extended period of observation following vaccination (30 minutes).
Ingredients in available COVID-19 vaccines
Pfizer-BioNTech Vaccine Ingredients:
- mRNA (medicinal ingredient)
- ALC-0315 = (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)
- ALC-0159 = 2-[(polyethylene glycol)-2000]-N, N-ditetradecylacetamide
- dibasic sodium phosphate dehydrate
- monobasic potassium phosphate
Moderna Vaccine Ingredients:
- mRNA (medicinal ingredient)
- 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)
- acetic acid, cholesterol, lipid SM-102
- tromethamine, tromethamine hydrochloride
- sodium acetate, sucrose, and water for injection
Note: Polyethylene glycol (PEG) is in both vaccines. It can also be found in laxatives, makeup, skin care products, personal lubricants, toothpastes, and some contact lenses. It is also in cough syrup, and in some food and drinks.
If you are unsure of the ingredients you are allergic to, talk to your health care provider.
Can people who are pregnant or breastfeeding get vaccinated?
Pregnant individuals may choose to receive the vaccine at any time during their pregnancy. It is recommended, but not required, that pregnant individuals have discussion with their treating health care provider, or with a health care provider familiar with their pregnancy, that includes:
- a review of the potential risks and benefits of the vaccine,
- a review of the risk of acquiring a COVID-19 infection during pregnancy,
- a review of the potential risks /consequences associated with a COVID-19 infection during pregnancy, and
- an acknowledgment of the limited evidence from clinical trials of COVID-19 vaccines in the pregnant population.
For additional information on COVID-19 vaccination in pregnancy:
- Video from Ontario health care providers (English, French, Arabic, Cantonese, Farsi, Mandarin, Spanish, Tamil, Vietnamese, Yoruba)
- Information on the COVID-19 vaccine and pregnancy (Prenatal Screening Ontario)
- Pregnancy & Breastfeeding Fact Sheet
- Society of Obstetricians and Gynecologists of Canada
- COVID-19 Vaccination Decision-Making Tool for People who are Pregnant
There is limited information on the use of COVID-19 vaccines while breastfeeding. Based on how mRNA vaccines work in the body, scientists do not believe there is a risk to the breastfeeding infant.
Breastfeeding individuals in the authorized age group (12+ for Pfizer BioNTech vaccine; 18+ for Moderna vaccine) may choose to receive the COVID-19 mRNA vaccine after speaking to a health care provider about the risks, benefits, and lack of specific research data.
Is it safe to get the vaccine while I am trying to get pregnant?
There is no scientific reason that the COVID-19 vaccines would impact fertility for those people trying to get pregnant. While fertility was not specifically studied in the clinical trials of the vaccine, no loss of fertility has been reported among trial participants or among the millions who have received the vaccines to date, and no signs of infertility appeared in animal studies.
If you are considering or undergoing IVF or fertility treatments, speak with your health care provider about vaccination. Some fertility specialists suggest waiting a cycle or two after vaccination before starting treatment (Source: https://sunnybrook.ca/content/?page=pregnancy-breastfeeding-fertility-covid-19-vaccine).
American College of Obstetricians and Gynecologists (ACOG), the American Society for Reproductive Medicine (ASRM), and the Society for Maternal-Fetal Medicine (SMFM)
Society of Obstetricians and Gynecologists of Canada: https://www.sogc.org/common/Uploaded%20files/Latest%20News/SOGC_Statement_COVID-19_Vaccination_in_Pregnancy.pdf
Can I get the COVID-19 vaccine while I am menstruating (having my period)? Will it affect my cycle? Will it make my period heavier?
People who menstruate (get a period) do not need to schedule their COVID-19 vaccine around their menstrual cycle. There are no issues with getting the vaccine during your period.
Delaying your vaccine around your cycle may leave you unprotected from COVID-19 for a longer time without providing any known benefit.
Menstruation can be influenced by many things, such as environmental changes, stress, sleep and some medications. When your immune system is working hard because you’re vaccinated or sick, you may experience changes in how the lining (endometrium) of the uterus responds so it is possible to see some changes in menstruation.
Researchers are confident that the vaccine is safe, and that there is not enough data to suggest that there should be concerns over potential changes to the menstrual cycle.
The good news is that any changes you experience in your menstrual cycle after getting the vaccine are temporary, so it shouldn’t be a reason not to get a shot. However, people with concerns should speak with their doctor since cycles can be delayed for other reasons as well.
Source: Immunize BC
These questions and answers were developed in collaboration with Hamilton's Vaccine Readiness Network.
Simplifying the science of vaccines
- COVID-19 vaccine: What you need to know (Ottawa Public Health)
- COVID-19: How vaccines are developed (Health Canada)
- Vaccine safety in Canada (Health Canada)
- Vaccine safety (Immunize Canada)
- COVID-19 vaccines (World Health Organization)
- Understanding how vaccines work (Yale School of Medicine)
- Vaccine hesitancy (Immunize Canada)
- COVID-19 vaccine (Dr. Evan Adams)
- Moderna vaccine creation
- COVID-19 vaccines (Public Health Ontario)
- How COVID-19 mRNA vaccines work (Health Canada)
- Answering patient questions about COVID-19 vaccines (Centre for Effective Practice)
Understanding mRNA vaccines
- Date modified: