Science Based Vaccine Information

Science Based Vaccine Information

Flu Facts Infographic


You may have reservations or questions about routine vaccinations and getting vaccinated. We know there are many reasons why people delay vaccination or decide not to get a vaccine.

Fear of needles is a big one.

You may also have questions about the safety, efficacy, or importance of vaccines. We understand this too. We know there is a lot of good information out there and a ton of misinformation as well. It can be hard, in some cases, to separate fact from fiction.

Barriers, such as a lack of transportation or not having a family doctor, can also prevent people from getting vaccinated.

Grey Bruce Public Health has compiled information and resources to help address some of the most common factors that may be preventing people from getting vaccinated.

Below, you’ll find answers to some of the commonly asked questions about the safety, efficacy, and importance of vaccination. We’ve also included information aimed at dispelling some of the myths you may have heard about vaccines and getting immunized.

Our When and Where immunization page includes some information aimed at helping people to overcome some of the most common barriers to vaccination.

If you have unanswered questions about vaccination, you can book a one-on-one call with a doctor through the free VaxFacts Clinic.

VaxFacts Clinic Logo

This service is provided by the Scarborough Health Network but is available to Canadians from coast to coast, including Grey-Bruce residents. You can book an appointment to speak with a doctor by visiting the VaxFacts website.

Judgement-free telephone consultations are available in more than 200 languages and the VaxFacts team of doctors includes family physicians, pediatricians, obstetricians, and other qualified specialists.

These doctors can discuss any vaccines, including childhood immunizations and influenza, COVID-19, or monkeypox vaccines.


What is the process for developing and approving vaccines in Canada?

Vaccines are a cornerstone of public health. Immunization has significantly contributed to preventing, controlling, and even eliminating infectious diseases in Canada and around the world.

Health Canada approves the use and sale of vaccines in Canada, only if they are shown to be effective, safe, of high quality, and with benefits that outweigh potential risks.

Vaccine manufacturers must file with Health Canada a New Drug Submission, which contains extensive data about the vaccine’s safety, efficacy, and quality, as well as the results of pre-clinical and clinical studies, details about production, and in-depth information on side effects and adverse reactions that occur after vaccination.

All approved vaccines are continuously monitored to ensure their safety, effectiveness, and quality are maintained. The ongoing monitoring of vaccine safety involves many groups, including federal and provincial governments and health agencies, public health units, health care providers, and the public.

This Government of Canada infographic depicts the vaccine approval process in Canada.

For more information:

Vaccines and treatments for COVID-19: Progress -

Vaccine Regulatory Process in Canada

Are vaccines approved for use in Canada safe?

The safety of vaccines is carefully monitored, starting early in product development and continuing for as long as the vaccine is available to the public.

For more information:

Vaccine Safety

Regulating vaccines for human use in Canada -

Vaccine Safety | immunizecanada

What are the possible side effects of vaccines?

Like any medication, vaccines can cause side effects and reactions. This is the body's natural response, as it's working hard to build immunity against the disease.

Vaccine side effects usually last from a few hours to a few days, and most do not disrupt daily activities.

Common reactions to vaccine(s) are mild, and may include:

  • redness
  • itching and/or rash at the injection site
  • headache or dizziness (less common)
  • nausea

Severe allergic reactions are very rare. The dangers of vaccine-preventable diseases are many times worse than the risks of a serious reaction to the vaccine.

Get medical attention immediately if you develop any of the following symptoms within 3 days of receiving an immunization:

  • hives
  • swelling of the mouth and throat
  • trouble breathing, hoarseness, or wheezing
  • high fever (over 40⁰C/104⁰F)
  • convulsions or seizures
  • or any other serious reaction to the vaccine

For more information:

Vaccine safety and possible side effects -

Vaccine Safety is important to all of us: Information for Parents

Why are vaccines important?

Routine vaccines protect people against very harmful and serious diseases, such as measles, polio, meningococcal, tetanus, and diphtheria. Vaccines are given to prevent you from getting a disease before it has a chance to make you sick.

Vaccines have saved more lives in Canada than any other medical intervention in the past half-century.

The World Health Organization says there are now vaccines to prevent more than 20 life-threatening diseases. The WHO estimates that immunization prevents about 3.5 million to five million deaths annually. They also protect against diseases that may not be deadly, but can cause pain and permanent disability.

Diseases like tetanus, whooping cough, and influenza are continually present in Canada. Other diseases are common in other parts of the world. Due to international travel, these diseases can easily arrive in Canada. It’s important to maintain high rates of immunization to keep them from infecting others and spreading.

For more information:

Vaccines: Common concerns | Caring for kids (

Addressing the myths about vaccines

Vaccines do not cause autism.

The original pop-culture connection between routine vaccinations and autism came from a discredited and retracted medical article in a UK-based journal, The Lancet, by a former British doctor. The doctor was de-licensed for “callous disregard” of children under his care by British medical authorities. You can read more about this example of fraudulent science, here.

Medical researchers and scientists around the world have not found a link between vaccines and autism.

Because children are vaccinated at around the same age as autism is often diagnosed, some people think vaccinations and autism are linked, but they are not.

For more information:

Talking about Vaccines: Autism (

Autism and Vaccines | Vaccine Safety | CDC

What ingredients make up vaccines and are any of the materials used in vaccines unsafe?

Each ingredient found in vaccines has an important role to play in ensuring the vaccine remains effective and safe. Each ingredient is found in small quantities and can be found naturally in the food we eat and in nature.

The main ingredients of a vaccine are dead or weakened viruses or bacteria.

Vaccines may also contain:

  • Adjuvants: to help the body’s immune system respond better to vaccines;
  • Additives and preservatives to help maintain the quality and effectiveness of the vaccine

Certain materials, such as thimerosal, formaldehyde, and aluminum, are used to kill bacteria and make vaccines as safe and effective as possible.

Will multiple injections overwhelm the immune system?

No. Every day, our bodies come into contact with millions of germs, causing our immune systems to work continuously to protect us. Therefore, exposure to antigens (parts of weak or dead viruses or bacteria) in vaccines is easily handled by our immune systems.

Even babies do not experience more side effects when more than one vaccine is given at a time. Vaccines are designed to protect your baby as soon as possible against more than one disease. Rather than overwhelming your baby's immune system, vaccines make the immune system stronger.

Can you get sick from vaccines?

No. Vaccines cannot make you sick and you cannot get the corresponding disease from the vaccine. Most vaccines do not contain live virus, and those vaccines that do contain live viruses cannot make you sick. Vaccines that have live viruses are severely weakened to the point that is enough to trigger an immune response, but not to cause any illness.


Vaccines - Immunization - Health Care Professionals - MOHLTC (

Questions and Answers | immunizecanada

Addressing COVID-19 vaccine myths

MYTH: Receiving a COVID-19 vaccine will make you magnetic or COVID-19 vaccines contain microchips.

FACT: There are no metals or microchips in the vaccines and they cannot make you magnetic.

  • Ingredients in the vaccines are publicly available and include fats, salts, sugars and the active ingredient. They do not contain any metals or any other contents that could cause magnetism.
  • Current microchips are not small enough to fit through the syringe of a vaccination needle and even if one could, it would not contain enough metal to hold a magnet through the skin.


MYTH: The COVID-19 vaccines cause infertility or miscarriage.

FACT: There is no link between COVID-19 vaccines and infertility or miscarriage.


MYTH: Pregnant and/or breastfeeding women should not receive the vaccine.

FACT: The vaccines are safe while pregnant and/or breastfeeding.

  • mRNA from vaccines does not transfer into breast milk.


MYTH: Genetic material in the COVID-19 vaccines will multiply in the body forever, changing your DNA.

FACT: The genetic material in the vaccines cannot affect or interact with our DNA in any way.

  • Health Canada-approved COVID-19 vaccines work by the mRNA teaching our cells to make a protein that then triggers an immune response, which causes our immune system to produce the antibodies needed to protect us from COVID-19 infection.
  • That genetic material is broken down and expelled by our bodies within a few days, it does not reproduce or replicate.
  • It is impossible for genetic material included in these vaccines to alter DNA because it does not enter the cells where our DNA lives.
  • Read more here: How mRNA COVID-19 Vaccines Work (PDF)


MYTH: People who are vaccinated can ‘shed’ the virus or spike proteins and infect others with COVID-19.

FACT: Individuals who have received the vaccine cannot shed or release any vaccine component.

  • Viral shedding happens when a person is infected with a virus and then whole viral particles are released from the body (through the nose or mouth for example).
  • To shed the SARS-CoV-2 virus, you actually have to have the live virus in your body.
  • None of the Heath Canada-approved COVID-19 vaccines contain a live virus, and therefore it would not be possible to shed it.
  • Once injected, the vaccines start to do their work near the site of injection so the spike protein produced there would not be found in respiratory droplets, and therefore, could not be shed.


MYTH: Corners were cut to develop a vaccine so quickly when it usually takes years.

FACT: The speed at which the vaccine was developed was thanks to unprecedented international collaboration and years of previous research.

The vaccines were developed quickly because of:

  • Global emergency partnerships and funding to support research, development, approval, and monitoring happened very quickly.
  • Quick adaptation of existing research into coronaviruses – scientists were not starting from scratch.
  • Quick sharing of the genetic code of the virus at the beginning of the pandemic.
  • Multi-tasking. Where possible, steps in the development process were done in parallel which normally would take years to complete step-by-step. For instance, normally, vaccine data is fully complete before sending it to Health Canada for approval. For COVID-19 vaccines, data review and analysis is happening in real-time as it comes in through the course of the clinical trials.

*Addressing COVID-19 vaccine myths resource Adapted from Wellington-Dufferin-Guelph Public Health


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