Vaccines & Safety

Pregnant individuals and their babies have a higher risk of developing severe complications (requiring hospitalization or intensive care) and death from a COVID-19 infection compared to non-pregnant individuals. COVID-19 illness in pregnancy increases the risk for stillbirth, preterm birth, high blood pressure, caesarean delivery and low birth weight. Getting the COVID-19 vaccine can help protect you and your baby from these complications.

While pregnant individuals were not included in initial COVID-19 vaccine clinical trials, real-world safety data is now available for hundreds of thousands of pregnant individuals who received COVID-19 vaccines and does not reveal any safety concerns for the pregnant individual or their baby.

COVID-19 vaccination during pregnancy builds antibodies which transfer across the placenta, providing protection to your baby. The benefits of COVID-19 vaccination for you and your baby outweigh the risk of serious COVID-19 illness and complications in pregnancy.

Several experts including the Society of Obstetricians and Gynaecologists of Canada (SOGC) (external PDF) and National Advisory Committee on Immunization (NACI) (external link) strongly recommend pregnant people get a complete COVID-19 vaccine series.

The COVID-19 vaccine is safe, effective and highly recommended if you are breastfeeding. Antibodies made by the mother’s body after receiving the COVID-19 vaccine, have been shown to pass into the breastmilk, which provides protection to your baby. It is safe to continue breastfeeding after COVID-19 vaccination.

Experts like the Society of Obstetricians and Gynaecologists of Canada (SOGC) (external PDF)) and the National Advisory Committee on Immunization (NACI) (external link), strongly recommend getting vaccinated while breastfeeding. It’s important to get vaccinated as soon as possible to protect you and your baby.

• COVID-19 vaccines do not cause male or female infertility and there is no evidence to suggest that they will cause infertility.
• In fact, getting fully vaccinated before you conceive will protect you and your future baby from the risk of COVID-19 in pregnancy.

Talk to your health care provider if you have any questions about getting the COVID-19 vaccine. More information is also available from these trusted resources:

• Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet (PDF file)
  • Available in Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet Arabic (PDF file), Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet Chinese (PDF file), Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet French (PDF file), Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet Punjabi (PDF file), Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet Spanish (PDF file) and Halton Region Public Health: COVID-19 Vaccine: Preconception, Pregnancy and Breastfeeding Fact Sheet Urdu (PDF file).
• Ontario Ministry of Health: COVID-19 vaccines in pregnancy (external link)
• Provincial Council for Maternal and Child Health (PCMCH): Vaccine information sheet (external PDF)
• Public Health Ontario: Evidence Brief COVID-19 Vaccines and Fertility (external PDF)
• Society of Obstetricians and Gynaecologists of Canada:
  • COVID-19 Vaccination in Pregnancy Understanding the risks of COVID-19 while pregnant (external link)
  • SOGC Statement on COVID-19 Vaccination in Pregnancy (external PDF)

• Mixing of mRNA vaccines (Pfizer and Moderna), as well as mixing AstraZeneca and an mRNA vaccine, is safe and effective.
  • Mixing similar vaccines to complete a vaccine series is routinely done for influenza, Hepatitis A, Hepatitis B, measles, and mumps vaccination.
  • Pfizer and Moderna vaccines use a similar mRNA technology. This means that you can get any mRNA vaccine recommended for your age.
  • Individuals who received a dose of AstraZeneca followed by an mRNA vaccine have similar protection as those who received a two doses of mRNA vaccines. For more information, see the statement from National Advisory Committee in Immunization (external PDF).
• Several countries around the world are safely mixing vaccine types.
• During clinical trials, both mRNA vaccines (Pfizer-BioNTech, Moderna) showed similar effectiveness, safety profiles and side effects (external link).
• All residents will receive an age-appropriate Health Canada approved vaccine.

The COVID-19 vaccine, like all vaccines, may cause side effects in some people. Symptoms are usually mild and resolve after a few days. Some of the symptoms are part of the body’s response to developing immunity to a virus.

Clinical trials of Pfizer (external link) and and clinical trials of Moderna (external link) third doses and real world data from Ontario (PDF file) show similar side effects from a third dose of either mRNA vaccine. Data also shows that serious side effects from the booster dose are very rare.

The most commonly reported side effects are:

• pain at the injection site
• swelling, and colour changes in the skin (for example, red, purple) at the injection site
• tiredness
• headache
• muscle or joint pain
• chills
• mild fever

Ongoing studies on the COVID-19 vaccines have found that serious side effects are extremely rare.

In rare cases, serious allergic reactions (anaphylaxis) can occur. Allergic reactions can be treated and are usually temporary. Contact your doctor if you develop any of the symptoms below. If your symptoms are severe, call 911.

• hives or itchy skin
• swelling of the face or mouth
• trouble breathing or wheezing
• serious drowsiness
• high fever (over 40°C)
• convulsions or seizures
• muscle weakness/ loss of feeling in the face
• chest pain, shortness of breath or excessive sweating
• feeling of a fast, pounding or fluttering heartbeat
• other serious symptoms (for example, “pins and needles” or numbness)

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.

Learn more about what to expect after vaccination.

Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) following vaccination with mRNA vaccines have been reported but are very rare. Cases are usually reported within a week after vaccination, most frequently:

• in adolescents and younger adults under 30 years of age;
• in males compared to females;
• after the second dose, and
• with the Moderna vaccine compared to the Pfizer vaccine.

Rates are significantly lower in children aged 5-11. (external PDF) The majority of people with myocarditis or pericarditis following vaccination tend to recover quickly and are treated with rest and/or anti-inflammatory medication(external PDF).

Seek medical attention right away if you develop any of the following symptoms after receiving the COVID-19 vaccine:

• chest pain;
• shortness of breath;
• heart palpitations (pounding or racing heart); or
• feeling of a rapid or abnormal heart rhythm.

Out of an abundance of caution, the Province recommends Pfizer vaccine for individuals aged 12 to 29 years old (external link). This is due to an increase of pericarditis/myocarditis following vaccination with Moderna compared to Pfizer in this age group (external PDF). Anyone aged 12 to 29 may receive Moderna, if requested.

The National Advisory Committee on Immunization (NACI) recommends that people who experience myocarditis (with or without pericarditis) within six weeks of receiving an mRNA COVID-19 vaccine should wait for more information before getting further doses (external link). These individuals may choose to get another dose of vaccine after discussing the risks and benefits with their healthcare provider. At Halton Region COVID-19 vaccination clinics, documentation from a health care provider is required to receive the next dose. Those who experience pericarditis and who either had no cardiac workup or had normal cardiac investigations can receive the next dose once they are symptom-free and at least 90 days has passed since vaccination.

Evidence continues to show that the benefits of COVID-19 vaccination far outweigh any potential risks. Becoming fully vaccinated can take us one step closer to resuming many of the activities we enjoyed prior to the pandemic.

For more information, please see Halton’s Myocardits and Pericarditis Fact Sheet (PDF file).

If you have questions or concerns about getting vaccinated for COVID-19, you can:

• speak with your primary health care provider (for example, family doctor, nurse practitioner, midwife); or
• connect by phone with a trained health care provider who can offer accurate information on getting vaccinated for COVID-19 as listed below

• Ontario Ministry of Health
  • COVID-19 Vaccine Information sheet (external PDF)
  • COVID-19 Vaccines for Ontario Youth (external link)
  • Questions about COVID-19 vaccines? Here are some answers. (external PDF)
• Government of Canada
  • Ask the experts video series: COVID-19 vaccine questions (external video link)
  • The facts about COVID-19 Vaccines (external link)
  • COVID-19 vaccines and Indigenous peoples (external link)
• Other
  • About Kids Health: COVID-19 Vaccines (external link)
  • Caring for Kids: COVID-19 vaccines for children and youth (external link)
  • Immunize Canada: COVID-19 Information for the public (external link)
  • National Institute on Aging: COVID-19 Vaccines – What Older Canadians Need to Know (external PDF)
  • Society of Obstetricians and Gynaecologists of Canada: COVID-19 Vaccination in Pregnancy (external link)
  • Women’s College Hospital: COVID-19 Vaccine: Multi-language Information (external link)