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Frequently Asked Questions about the COVID-19 Vaccine

Niagara Region Public Health and Emergency Services is closely monitoring the COVID-19 pandemic. This is an evolving situation and we'll continue to update information as it becomes available.

Updated Sept. 13

Second dose

  • Why do I need a second dose?

    It's great that you got your first dose of the COVID-19 vaccine. You need to get a second dose to ensure you have long-lasting protection.

    The first dose of a two-dose vaccine lets your body's immune system know what it needs to do to fight COVID-19. The second dose is the one that really gives your immune system the boost that's critical for long-term protection.

  • It has been more than four months since my first dose. Can I still get a second dose or do I need to restart my vaccination series?

    Full vaccination is the greatest protection you can have against COVID-19 and its variants. It's not recommended that individuals wait.

    If it's been more than four months since your first dose, you don't need to restart the series. However, Public Health does recommend you get your second dose as soon as possible to ensure maximum protection.

  • My first dose was AstraZeneca. What will happen with my second dose?

    If you received your first dose of AstraZeneca, you did the right thing to prevent the risk of infection and death from COVID-19 as early as possible. AstraZeneca is safe and effective to prevent COVID-19 and it reduces the risk of infection and death from COVID-19.

    For your second dose, the province indicates that you may:

    • Get a second dose of the AstraZeneca vaccine, OR
    • Get an mRNA vaccine (Moderna or Pfizer) as your second dose.
      • The National Advisory Committee on Immunization recommends an mRNA vaccine is preferred for a second dose due to emerging evidence including the possibility of better immune response and the safety of mixing vaccine brands for first and second doses

    Choosing either of these options will count as a completed COVID-19 vaccination series. With informed consent, you're eligible for either of these options at least eight weeks after your first dose of AstraZeneca.

    On June 14, 2021, the province updated the second dose interval to as early as eight weeks for those who got a first dose of AstraZeneca. This is based on studies that show dosing intervals between eight and 12 weeks is safe and gives a beneficial immune response.

    There is evidence that a longer interval between two doses of the AstraZeneca vaccine (such as a 12-week interval) gives higher protection. However, some may choose to get their second dose sooner to have the increased protection that the second dose gives earlier.

    We encourage you to speak with a health care professional for help understanding the options available so you can make an informed decision on your vaccination.

    Choosing a second dose of AstraZeneca:

    • The unusual clotting syndrome that seems to occur after this vaccination is very rare. There are very good treatments for it if it does occur. Ontario paused using AstraZeneca for first doses out of an abundance of caution and because of increased supply and availability of mRNA COVID-19 vaccines (Moderna and Pfizer).
    • The rate of this clotting syndrome after second dose appears to be lower than after the first dose

    Completing your vaccination series with an mRNA vaccine:

    • The concept of using different vaccine products to complete a vaccine a series is not new
    • Studies show that a first dose of AstraZeneca followed by a second dose of mRNA vaccine is safe and will boost your immune response against COVID-19 for that long-term protection. These studies used Pfizer as the second dose.
    • Countries in Europe including Denmark, Finland, France, Germany, Norway, Spain and Sweden have already been offering either Moderna or Pfizer to those who had a first dose of AstraZeneca
    • With an mRNA as your second dose, there is evidence of increased short-term, mild side effects such as headache, fatigue and feeling generally ill. These symptoms don’t last long and resolve without complications.

    If your first dose was the AstraZeneca, and you’d like to receive AstraZeneca as your second dose:

    • You will be eligible to receive your second dose at an interval of eight weeks or more
    • Contact the pharmacy or primary care provider where you had your first dose to book an appointment. They may also call you to let you know that you can book an appointment.

    If your first dose was the AstraZeneca vaccine, and you’d like to receive an mRNA vaccine (Moderna or Pfizer) as your second dose:

  • My first dose was Moderna or Pfizer. Will my second dose be the same vaccine?

    Public Health plans to have both mRNA vaccines (Moderna and Pfizer) based on vaccine availability. When possible, you will be offered the same vaccine that you got at your first dose appointment. If that mRNA vaccine is not readily available, another mRNA vaccine will be offered to complete the vaccine series.

    This is based on guidance from the National Advisory Committee on Immunization that says the Moderna and Pfizer COVID-19 vaccines can be safely interchanged. This means you can switch between Moderna and Pfizer safely if the original vaccine you got is not readily available.

    Some people have found the concept of mixing vaccine brands confusing. Think of it like multiple companies producing bottled water. They have different labels, but are essentially the same product. When this happens with vaccines, it allows us to mix and match vaccine products if we need multiple doses of a vaccine.

    It's important to know that:

    • The National Advisory Committee on Immunization includes both clinical trials of each vaccine brand that aren’t mixed, as well as research studies in the real world from several countries that are mixed, to make their recommendations
    • Mixing vaccine brands is not a new concept. This happens with other vaccines when vaccine supply or public health programs change. For example, different vaccine products have been used to complete a vaccine series for measles, mumps and rubella (MMRII or Priorix), meningococcal-C-C (Menjugate Liquid or NeisVac-C), and hepatitis B (Engerix-B or Recombivax HB), etc.
    • With COVID-19 vaccines, both Moderna and Pfizer are built on the same mRNA technology. The two vaccines are so similar, they are completely interchangeable.

    Learn more about mixing vaccines for first and second doses. Watch Dr. Hirji's, Niagara's Medical Officer of Health (Acting), video on COVID-19 Vaccinations in Niagara FAQs: Is it safe to mix vaccines for first and second doses?

  • What are side effects like after a second dose?

    Side effects after your second dose can be similar to the ones you may have had after your first dose but they only last about one to three days. These symptoms typically mean that your body is building protection. If you don't get the second dose, you won't be fully protected from COVID-19.

    If your first dose was AstraZeneca, you're getting an mRNA vaccine for your second dose:

    • There is evidence of increased short-term, mild side effects, such as headache, fatigue and feeling generally ill
    • These symptoms don't last long and resolve without complications

General information

Vaccine safety

  • How safe are COVID-19 vaccines?

    We know you want to be sure that COVID-19 vaccines are safe. To help you decide if the vaccine is right for you, watch Dr Hirji's video where he answers questions about safety of the vaccines.

    We've sacrificed so much this year to keep our loved ones and community safe. You can play a big role to fight COVID-19 by getting the vaccine when you can.

  • How do I know that I won't get COVID-19 from the vaccine?

    There is no COVID-19 virus in the vaccine. The vaccines teach your immune system how to recognize and fight the virus that causes COVID-19.

    Some people may develop mild side symptom such as fever. These symptoms typically mean the vaccine is working to produce protection. It usually takes the body a few weeks to build immunity after receiving a vaccine.

    You can become infected with the virus before or right after getting the vaccine. This happens because the vaccine has not had enough time to provide protection in your body.

  • What do I need to know about the long-term safety of mRNA vaccines?

    From the science and history of vaccines, there is no evidence of long-term effects.

    Vaccines introduce proteins from a dangerous germ to the body’s immune system. In this way, the body can learn to identify and fight those germs off. Within a couple of weeks, no traces of the vaccine are left in the body. This is because the immune system destroys the proteins. Any other elements of the germ are quickly broken down.

    Like any medication or supplement (including vitamins), there’s a chance that there will be a serious side effect. These are rare, but they do happen. When it does, it's usually in the short term when the vaccine is stimulating the immune system. Learn about how Canada makes sure vaccines are safe for you and your family.

    It's far more likely that mRNA vaccines will be like other vaccines. Here's what you need to know about mRNA vaccines:

    • mRNA vaccines are a new vaccine platform, but not a new technology. mRNA therapeutics have been studied for over two decades. Recent scientific advancements have improved mRNA stability and delivery. This has allowed mRNA vaccines and cancer mRNA therapeutics to be put into clinical use.
    • mRNA vaccines provide instructions to the body to produce a coronavirus protein. The body then recognizes the protein as foreign. These proteins use the body's normal processes to safely produce an immune response. As soon as it is finishing using the mRNA's instructions, the body breaks down and gets rid of the mRNA.
    • Once the mRNA breaks down, the body doesn’t have the ability to produce more of this foreign mRNA. So there’s nothing left of the vaccine long-term. The only long-term impact of the vaccine is immune memory against COVID-19.
    • The safety of COVID-19 vaccines are closely monitored. Any safety issues are responded to right away and Canadians are informed about any risks that arise.
  • How do I know that the vaccine won't change my DNA?

    The vaccine doesn't change your DNA in any way.

    The mRNA from a COVID-19 vaccine never enters the nucleus of the cell, which is where our DNA are kept. This means the mRNA doesn't affect or interact with our DNA in any way. Instead, COVID-19 vaccines that use mRNA work with the body's natural defences to safely develop protection (immunity) to disease.

  • Can I get the vaccine if I have a health condition?

    People with stable health conditions can get vaccinated. Conditions include: diabetes, high blood pressure, heart disease, respiratory diseases, including asthma or COPD, hepatitis B, C and HIV.

    People with a weak immune system because of illness, treatment or an autoimmune condition:

    • Can get the vaccine safely
    • Should speak to their health care provider before getting vaccinated
    • May have lower protection from the vaccine

    People taking medication that make their immune system weak may be able to schedule their vaccine and treatment to get the best protection.

    Watch family physician, Dr. Dec, talk about the importance of people who have a health condition getting vaccinated.

  • How were the COVID-19 vaccines developed so fast?

    The rapid development was made possible by decades of advances in vaccine technology. Specific research into coronaviruses gave a head start to developing a COVID-19 vaccine. Watch COVID-19: How vaccines are developed.

  • Can I get the vaccine if I'm pregnant?

    Yes. You can get vaccinated at any time during your pregnancy. The National Advisory Committee on Immunization preferentially recommends that a complete vaccine series with an mRNA COVID-19 vaccine be offered to pregnant individuals.

    Watch a short video from Niagara Health's Chief of Staff, Dr. Johan Viljoe, about getting the vaccine while you're pregnant.

    The risk of infection and death from COVID-19 outweighs any risk of being vaccinated during pregnancy. During the third wave we just experienced, people who were pregnant were at high risk of being hospitalized with COVID-19.

    Adding to this concern:

    • Ventilator support in pregnancy is challenging, with greater risks to the pregnant individual and child
    • Pregnant individuals with COVID-19 have an increased risk of premature delivery, caesarean delivery and admissions of their babies to a neonatal unit

    While not required, it's best to speak with your health care provider to help you decide if the vaccine is right for you. This is particularly important because early clinical trials didn't include participants who were pregnant. However, small numbers of individuals in the trials were found to be pregnant after vaccination. These pregnant individuals haven't reported adverse events to date and continue to be followed. Clinical trials are ongoing and some manufacturers have started new trials that include pregnant individuals. As more evidence becomes available, vaccine recommendations will be reviewed and updated.

    Learn more about getting vaccinated when pregnant, planning for pregnancy, or breast/chest feeding.

    Pregnancy care providers in Ontario are sharing a video message for pregnant individuals in multiple languages.
  • Can I get the vaccine if I'm breastfeeding?

    Yes. You can get any of Canada's approved COVID-19 vaccines when you're breastfeeding. The National Advisory Committee on Immunization preferentially recommends that a complete vaccine series with an mRNA COVID-19 vaccine be offered to breastfeeding individuals.

    Recent data shows that mRNA from vaccines don't transfer into breast milk. Anti-COVID-19 antibodies produced by the breastfeeding person have been shown to transfer through the milk and provide protection to the infant. The vaccines are safe for the breastfeeding person.
  • Can the vaccine impact my ability to get pregnant?

    No. According to the Society of Obstetricians and Gynecologists of Canada, there is no evidence or reason to suspect that the COVID-19 vaccine could impair male or female fertility.

    While the proteins syncytin-1 (used for placental implantation) and the SARS-CoV-2 spike protein have several similar amino acids, they remain vastly different. The antibodies produced against the SARS-CoV-2 spike protein will not block syncitin-1.

    The concern around fertility seems to have started as a random internet rumour that has taken off. Some people who voice this concern speak of “fertility research” around this vaccine. However, no such research exists. This is all driven by rumor on the Internet.

    Unfortunately, during the third wave we just experienced, people who were pregnant were at high risk of being hospitalized with COVID-19. If anything, those planning to become pregnant soon are at greater need to be vaccinated than others.

    For accurate and evidence-based advice, visit the Society of Obstetricians and Gynecologists of Canada. Check the reliability of any online news before sharing.

  • If I had a reaction to a different vaccine in the past, can I still get the COVID-19 vaccine?

    Most people who had a reaction to a prior vaccine can safely receive the COVID-19 vaccine. Check with your doctor or health care provider if you have had a serious allergic reaction to a vaccine in the past. They will look at your medical records and advise you accordingly.

  • Is it acceptable for someone with food or seasonal allergies to receive the COVID-19 vaccine?

    Yes. If you have allergies that are not related to any components of the COVID-19 vaccine, you can still be vaccinated.

  • Who should not get the vaccine?

    People who have had a serious allergic reaction, such as anaphylaxis, to a component of the COVID-19 vaccine cannot receive the vaccine. Others who have had a less serious, but immediate allergic reaction, should see their health care provider for guidance.

    Viral vector vaccine

    AstraZeneca is a second dose option only for those who received it as a first dose and are 40 years of age or older. However, you cannot get AstraZeneca as a second dose if you have:

    • A history of capillary leak syndrome
    • Experienced venous or arterial thrombosis with thrombocytopenia following vaccination with a viral vector COVID-19 vaccine

    See "My first dose was AstraZeneca. What will happen with my second dose?" in the second dose section.

    mRNA vaccine

    • If you have an allergy to polyethylene glycol, you should not get vaccinated if your past reaction was severe
    • If you experienced myocarditis (heart inflammation) and / or pericarditis (inflammation of tissue around the heart) after a first dose of an mRNA vaccine, you should wait to get your second dose until more information is available
  • What do I need to know about reports of myocarditis (heart inflammation) and/or pericarditis (inflammation of tissue around the heart) and COVID-19 vaccination?

    Heart inflammation (myocarditis and/or pericarditis) after receiving an mRNA COVID-19 vaccine is rare. These reports are being investigated to determine if they're directly related to mRNA vaccination.

    It's important to know that this condition is rare, usually mild, easily treated, and individuals tend to recover quickly. The National Advisory Committee on Immunization continues to strongly recommend that a complete series with an mRNA vaccine be offered to all eligible individuals 12 years of age and older who do not have contraindications. Based off safety and effectiveness data, Ontario also recommends all youth born in 2009 (turning 12 years old before the end of 2021) get vaccinated.

    When it does happen, it seems to be:

    • More often after the second dose
    • Usually within a week after vaccination
    • More often in youth and young adults under 30 years of age
    • More often in males than females

    If you experience symptoms such as chest pain, shortness of breath, or the feeling of a fast, pounding or fluttering heartbeat, seek immediate medical attention.

    Speak to your health care provider if you have questions about getting an mRNA vaccine or if you did experience the symptoms above after receiving your first dose. As a precaution, National Advisory Committee on Immunization recommends that individuals who experienced heart inflammation after a first dose of an mRNA vaccine should wait to get their second dose until more information is available.


Getting ready for your vaccine appointment

After being vaccinated

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