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.

See frequently asked questions on:

Updated Jan. 14

Third doses and booster doses

  • Why are third dose or booster doses needed?

    The National Advisory Committee on Immunization was recommending that certain populations get a third or booster dose even before Omicron was identified as a variant of concern. This was based on evidence that showed protection from the vaccine may decrease over time. A booster dose of an mRNA COVID-19 vaccine is safe and produces a very good immune response that is generally higher than the immune response after the primary series.

    Although vaccines are less effective against Omicron infection, boosters can substantially increase protection. Early evidence suggests that a third dose or booster can further increase protection against severe illness and hospitalization. This is why Ontario rapidly expanded eligibility for third and booster doses. It's critical that everyone receives their third or booster dose when they become eligible for best protection against COVID-19. This will also help protect Ontario’s hospital capacity.

    Learn who is eligible for a third dose or booster dose and how to book an appointment.

    If you haven’t already done so, it’s also critical that you receive your first or second dose. According to the Ontario COVID-19 Science Advisory Table, even two doses is likely to provide strong protection against severe illness due to the Omicron variant.

  • Which vaccine will I get for my booster at a Public Health clinic?

    Individuals under 30 years of age:

    Pfizer - Reports of myocarditis (inflammation of the heart) and pericarditis (inflammation of the tissue surrounding the heart) remain rare after vaccination. When it does happen, it seems to be more often in young adults - particularly those under the age of 30. The evidence suggests it's more common following vaccination with Moderna compared to Pfizer.

    Individuals 30 years of age and older:

    Moderna - Ongoing research suggests that over time, Moderna has less waning immunity and maintains a high effectiveness - especially in older adults. This means you're likely to have longer lasting and potentially stronger protection with the Moderna vaccine compared to Pfizer.

  • The recommended vaccine for my booster dose is different from my previous doses. Is this okay?

    Yes. Moderna and Pfizer vaccines use a similar mRNA technology. This means the vaccines are interchangeable and safe to mix. Canada's National Advisory Committee on Immunization made this recommendation after carefully reviewing research on safety and effectiveness. Countries around the world, including the United States, are also using a different vaccine for the booster dose as compared to the previous doses.

  • When is it necessary to reschedule an appointment?

    Visit getting vaccinated to learn about the reasons to reschedule your appointment.

Second dose

  • Why do I need a second dose?

    Getting your second dose of COVID-19 vaccine is still critically important as we face the Omicron variant. The Ontario COVID-19 Science Advisory Table stated that even two doses is likely to provide strong protection against severe illness due to the Omicron variant until you can get the booster to help increase your protection after your second dose. The risk of severe illness from COVID-19 is much higher in those that are unvaccinated.

    In Ontario, you also need a second dose to enter settings where proof of vaccination is required.

    Learn how you can get vaccinated in Niagara.

  • It's 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. 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, you may get an mRNA vaccine (Moderna or Pfizer). The National Advisory Committee on Immunization recommends an mRNA vaccine 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. This will count as a completed COVID-19 vaccination series.

    You may receive your second dose of an mRNA vaccine eight weeks after your first dose of AstraZeneca.

    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.

    Learn how you can get vaccinated in Niagara.

  • 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.

General information

  • If others around me are getting vaccinated, why should I? Isn't that enough to protect me?

    Vaccination rates are not high enough globally or locally to protect unvaccinated individuals from COVID-19. Most COVID-19 infections are in unvaccinated people. Cases among fully vaccinated individuals are far less likely.

    When you and your child get a COVID-19 vaccination, you're protecting yourselves from the risk of serious illness and death. You're also helping those who are unable to get vaccinated for medical reasons or children who are too young to receive the vaccine.

    Health Canada approved vaccines have passed quality and safety standards and provide strong protection against COVID-19.

  • Is there a difference between the Moderna and Pfizer vaccines?

    Moderna and Pfizer are basically the same vaccine, made with the same technology. They are just made by different companies. You can be confident that you're getting protection from COVID-19 with both vaccines. Both vaccines will help you protect everybody around you as well. Public Health plans to have both mRNA vaccines (Moderna and Pfizer) at our clinics based on vaccine availability.

    Learn more from Dr. Hirji's video about Moderna and Pfizer vaccines.

  • Can I get my vaccine if I don't have a health card?

    Yes. Visit getting vaccinated to learn how.

  • Are there side effects from COVID-19 vaccines?

    Similar to other vaccines, some people may develop mild side effects after receiving a COVID-19 vaccine, such as pain where the needle was given, tiredness, chills, headache, and muscle pain. These symptoms typically mean the vaccine is working to produce protection. These side effects usually go away in one to three days. Serious side effects are extremely rare.

    You can play a big role to fight COVID-19 by getting the vaccine.

  • If I had COVID-19, should I still get the vaccine?

    Yes, you should still get your vaccine. If you had COVID-19, you may have some immunity but we don't know how much or how long it may last.

    To learn about the specific timeframe for when you can come to a Public Health clinic to get vaccinated after a COVID-19 infection, visit getting vaccinated (see "Reasons to reschedule your appointment" section).

  • Why should I get vaccinated if the COVID-19 infection has a high survival rate?

    COVID-19 can be a serious illness for anyone and for some people symptoms can last for months. The vaccine is safe and virtually eliminates the risk of serious illness and death.

    Watch Dr. Hirji speak about how well the vaccine is working.

    Visit our monitoring statistics page to see the risk of COVID-19 infection in Niagara among unvaccinated people compared to fully vaccinated people, and people vaccinated with one dose compared to fully vaccinated people.

  • Will the vaccine protect me from variants?

    All viruses, including the virus that causes COVID-19, mutate over time. A virus with one or more mutations is a variant. Some mutations can change the characteristics of a virus, such as how it spreads, making it a variant of concern. COVID-19 variants of concern include:

    • Alpha (B.1.1.7) - first identified in the United Kingdom
    • Beta (B.1.351) - first identified in South Africa
    • Gamma (P.1) - first identified in Brazil
    • Delta (B.1.617) - first identified in India

    You can see Niagara's daily case count for these variants.

    We're concerned about these variants because they:

    • Appear to spread more easily and quickly than other variants
    • Increase risk of severe illness and death

    All variants may increase the risk of re-infection for people who already had COVID-19.

    All Health Canada approved vaccines provide strong protection against COVID-19 and its variants, including the Delta variant.

    Actions you take to prevent COVID-19 will protect you against variants. Get vaccinated and prevent the spread of COVID-19.

  • How do I report an adverse event following immunization?

    Vaccine reactions are rare. Risks of a serious reaction from a vaccine are minor compared to getting the actual disease. If you have experienced an adverse event after your vaccine, learn how to report adverse events.

    For more details, visit reported side effects following COVID-19 vaccination in Canada.

Vaccine safety

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 answer questions about vaccine safety.

  • 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.

    Vaccine side effects usually happen within a few days, and always within six weeks. Vaccines are quickly broken down and removed from your body, and so cannot cause side effects many months or years later. The only lasting impact of vaccination is the training it provides your immune system.

    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:

  • 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 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 should also be vaccinated. However, they may receive lower protection from the vaccine.

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

    Certain immunocompromised individuals are eligible for a third dose. Learn who is eligible for a third dose or booster dose and the required proof of eligibility.

  • 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.

  • 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?

    Both myocarditis and pericarditis are more common after COVID-19 illness (a viral infection) than after vaccination.

    While there have been rare reports of myocarditis / pericarditis after vaccination, the majority of cases have been mild, easily treated and individuals recover quickly.

    Learn more about myocarditis / pericarditis and COVID-19 vaccines.

Getting ready for your vaccine appointment

After being vaccinated

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