COVID-19 - Get vaccinated and find public health advice for residents and businesses.

After Vaccination

Thank you for vaccinating

With every vaccination, you're protecting you and your child from serious diseases. You're also protecting people around you who may be at risk for disease.

Watch the video: immunity and vaccines explained.

Common side effects

Most individuals don't experience any serious side effects after receiving a vaccine. The most common side effects are usually mild and may include the following:

  • Pain, swelling, or redness where the vaccine was given
  • Mild fever
  • Headache
  • Tiredness
  • Muscle or joint aches

Common side effects don't have to be reported. If your symptoms worsen, contact your health care provider or go to the closest hospital.

Serious side effects

In rare cases, an individual may have a serious allergic reaction. The risks of a serious reaction from a vaccine are minor compared to getting the actual disease.

There is a 15-minute wait time after a vaccination to make sure that there are no immediate reactions.

After receiving a vaccination, it's important to monitor yourself or someone in your care for a few days. Pay attention for any of the following symptoms or reactions:

  • A fever higher than 40 degrees Celsius (104 degrees Fahrenheit)
  • Increased swelling where the vaccine was given
  • An allergic reaction. For example, a rash, hives or anaphylaxis.
  • Severe vomiting or diarrhea
  • Any other unusual or unexpected event

What to do if you're concerned

If you're concerned about how you or someone you're caring for looks or feels after a vaccine:

Report adverse events (health effects after vaccination)

An adverse event following immunization is called an AEFI. They are classified as:

  • An unwanted or unexpected health effect that happens after someone receives a vaccine
  • A health effect that may or may not be caused by the vaccine

Vaccine safety is taken very seriously in Canada. Reporting an adverse event is important to ensure continued safety of vaccines. Health care providers who administer vaccines are required by law to report an adverse event following immunization.

Most reported adverse events are mild. The most frequently reported reactions are:

  • Pain, redness or swelling at the injection site that lasts more than four days or extends past a joint
  • Rash
  • Allergic skin reaction

For information specific to children and adverse events, see the AEFI fact sheet for parents.

To learn more about vaccine safety and surveillance, visit Public Health Ontario's vaccine safety and surveillance tool.

How to report adverse events

Not all reactions are considered reportable adverse events. Most reportable adverse events must be diagnosed by a physician. These reactions are marked with an asterisk (*) in section 3 of the adverse event form. Some adverse events may need medical treatment.

We recommend and encourage individuals to have the adverse event form filled out by a health care provider. Otherwise, individuals can complete the adverse event form themselves for any adverse events that do not require physician diagnosis and submit the report to the Vaccine Preventable Disease program at Niagara Region Public Health.

  • Fax: To ensure secure transmission, fax the completed form to 905-688-8225
  • Email: If you're unable to fax, email the completed form to The contents of the email message and any attachments are intended solely for the purposes of submitting an adverse event form.

The adverse event form involves personal health information. Communications by email are not secure and / or protected. There is a possibility that information you include in the email can be intercepted in transmission or misdirected. Niagara Region Public Health cannot guarantee security with emails. Niagara Region Public Health will not send emails that include your personal health information.

If you have questions about reporting an adverse event related to COVID-19 vaccine(s), call the COVID-19 Info-Line at 905-688-8248 or 1-888-505-6074 press 7.

For questions about reporting adverse events for non-COVID-19 vaccine(s), call the Vaccine Team 905-688-8248 or 1-888-505-6074 ext. 7425.

After COVID-19 vaccine

To learn more about common side effects from COVID-19 vaccines, visit the Ministry of Health's after your COVID-19 vaccine fact sheet or our frequently asked questions about the COVID-19 vaccine.

For COVID-19 vaccine information, call the Provincial Vaccine Information Line at 1-888-999-6488.

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