Serious side effects due to the vaccines were not seen in the clinical trials. The people who received the vaccines in the clinical trials continue to be monitored for any longer-term side effects. A number of processes are in place in Canada to monitor the safety of the vaccines as more people get immunized.
Common reactions to the vaccines may include soreness, redness, swelling and itchiness where the vaccine was given. For some people, these reactions may show up eight or more days after getting the vaccine. Other reactions may include tiredness, headache, fever, chills, muscle or joint soreness, swollen lymph nodes under the armpit, nausea and vomiting. These reactions are mild and generally last one to two days. If you have concerns about any symptoms you develop after receiving the vaccine, speak with your health-care provider or call 8-1-1 for advice.
It is important to stay in the clinic for 15 minutes after getting any vaccine because about 1 in a million people can have a life-threatening allergic reaction called anaphylaxis. This may include hives, difficulty breathing, or swelling of the throat, tongue or lips. Should this reaction occur, the health-care providers on site are prepared to treat it. If symptoms develop after you leave the clinic, call 9-1-1 or your local emergency number. Always report serious or unexpected reactions to your health-care provider.