Health Canada reported that side effects that followed administration of the AstraZeneca vaccine were mild or moderate and are common of many vaccines (external link), including:
- pain at the site of injection
- body chills
- feeling tired
- feeling feverish
On March 24, 2021 Health Canada issued a label change and guidance on the AstraZeneca COVID-19 vaccine following reports of a very rare combination of thrombosis and thrombocytopenia (external link) following vaccination with the AstraZeneca COVID-19 vaccine. These blood clots have two important features: they occur four to 20 days after vaccination, and they are associated with low platelets (tiny blood cells that help form blood clots to stop bleeding). Individuals should seek medical attention if they develop the following symptoms after receiving the AstraZeneca COVID-19 vaccine:
- shortness of breath
- chest pain
- leg swelling
- persistent abdominal pain
- neurological symptoms (such as sudden onset of severe or persistent worsening headaches or blurred vision)
- skin bruising
- petechiae (small, red or purple spots on the skin)
While there are rare reports of side effects from AstraZeneca, it is important to note that to date, there have been no cases of these events reported in Canada. A summary of the reported information is available on Canada.ca/coronavirus (external link). Cases reported have primarily been women under the age of 55 years. The rate of the adverse event is still to be confirmed, though it is estimated to be 1 in 100.000 to 1 in 1,000,000 people vaccinated. As a safety precaution, use of AstraZeneca COVID-19 vaccine for individuals under age 55 (external link) is currently paused in Ontario while this investigation is underway.
Health Canada has determined that the benefits of the AstraZeneca/COVISHIELD vaccine in protecting Canadians from COVID-19 continue to outweigh the risks (external link). Adults over the age of 55 and older will be offered the AstraZeneca vaccine as there is an increased risk of hospitalization and death due to COVID-19 in this population and there have been fewer reports of Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) events in this age group.
COVID-19 has been associated with causing blood clots, so all COVID-19 vaccines continue to be recommended for people who have had a blood clot in the past, or who have a family history of blood clots and who are receiving blood thinning medications.
Speak with your health care professional about any serious allergies or health conditions before receiving the AstraZeneca COVID-19 vaccine.
Vaccine side effects will continue to be monitored as people receive the vaccine. If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects to make sure the vaccine continues to be safe.