Seunga (Jasmine) Han, PharmD Student
With flu season being just around the corner, we’ve been covering various topics regarding the flu shot, such as what influenza is, how we can prevent it, why we need the flu shot, and the differences between the flu, the common cold and the stomach flu. Continuing this series, today’s article will explore what implications pregnancy has during flu season.
Pregnancy can be a stressful time for any woman, especially when it comes to figuring out what’s safe and harmful to the unborn fetus. This is a common concern for many new moms, and, as such, we would like to help address any misconceptions behind the flu shot and pregnancy.
I’m pregnant. Should I get the flu shot?
In short, yes. It’s important to receive your flu shot, and this can be done anytime during your pregnancy. It’s important to understand that when you’re pregnant, you’re at a higher risk for serious complications from influenza, which can put you at risk of being admitted to the hospital. These complications can be harmful to your baby and lead to problems like premature birth or low birth weight.1,2
So, getting the flu shot protects not only you but your baby as well.
But, is it safe?
Again, yes! Studies show that receiving the flu shot during pregnancy is safe for the baby and the mother. This is because the injectable versions of the influenza vaccine in Canada are inactivated vaccines, meaning that the virus in the vaccination has been “killed”. While it can cause some chills, muscle aches and soreness at the site of injection, the flu vaccine cannot cause the flu. 1,2
However, there is another influenza vaccination available in nasal spray form, and this is not recommended for pregnant women since this is a “live” influenza vaccine. This means that the virus has been modified and has the ability to cause more symptoms. While these symptoms are milder than the real flu, it’s still best to avoid the intranasal vaccine in pregnant women. 1
But, what about thimerosal in vaccines?
Let’s first talk about what thimerosal is. Thimerosal is a preservative that is used in some vaccines. It often breaks down in the body quickly and is eliminated in the stool.
Contrary to popular beliefs, thimerosal isn’t the same as methylmercury (found in contaminated fish) or phenylmercury (a chemical for killing fungus). These can build up in the body, unlike ethyl mercury, which is what thimerosal is broken down into.
Not only is thimerosal found in small amounts in those vaccines that use it as a preservative, but studies have also shown that the amount found in vaccines is safe in pregnant mothers and for the unborn baby.
At the end of the day, the flu shot continues to be a safe and effective method of not only preventing the flu but reducing the severity of illness if you were to get vaccinated and become sick anyway (this is possible, just very unlikely). On the other hand, the effects of the flu on a pregnant mother and her developing unborn child are very significant and should be considered heavily when planning for the health of the pregnancy. Fortunately, flu shots are widely available and typically free in most regions – in the end, almost anyone and everyone can be expected to safely benefit from the flu shot.
We hope you took away something valuable from this piece. If you have any questions or concerns regarding this article or others, feel free to reach out to us on Instagram, Facebook, or at email@example.com with your feedback. We’d love to hear from you.
- Influenza Immunization for Pregnant Women, Breastfeeding Women, and Families with Newborns[PDF]. (2017, September 1). Alberta Health Services.
- Influenza (Flu). (2017, October 03). Retrieved September 18, 2018, from https://www.cdc.gov/flu/protect/vaccine/qa_vacpregnant.htm
- Thimerosal Information Sheet [PDF]. (2018, September 5). Alberta Health Services.