In this booklet:
- How were the vaccines developed so quickly?
- Will my DNA be altered by the vaccine?
- Is the COVID-19 vaccine safe for people with sickle cell disease?
- Does the vaccine cause blood clots?
- Is it safe to take the vaccine while taking hydroxyurea?
- Do I still need the vaccine if I have contracted COVID-19?
- Will the vaccine cause fertility issues?
- Can I get the vaccine if I am pregnant?
- mRNA vaccines: how do they work?
How were the vaccines developed so quickly?
The development of mRNA vaccines can be traced back as far as the 1970s but had not yet been tested in real-world conditions when the COVID-19 pandemic began.
Due to medical urgency, manufacturers of these vaccines were provided additional government funding to begin mass production, and emergency authorization to begin using them, even before clinical trials had been completed. These trials have now demonstrated that these vaccines are extremely safe and effective, and Health Canada granted full approval in December 2020.
Will my DNA be altered by the vaccine?
There is absolutely NO evidence to suggest that vaccines will change or alter human DNA in any way. Instead, the COVID-19 vaccine tells your immune system to create antibodies. These antibodies fight the COVID-19 virus.
Is the COVID-19 vaccine safe for people with sickle cell disease?
While the precise number of individuals with sickle cell disease who have been vaccinated against COVID-19 is unknown, available data suggest it numbers in the tens of thousands. Even with this high degree of uptake, reports of serious adverse effects of COVID-19 vaccination in sickle cell patients are vanishingly small. Vaccination against COVID-19, particularly with the vaccines available in Canada, can therefore be considered extremely safe in patients with sickle cell disease.
Does the vaccine cause blood clots?
There are no increased risks of blood clots from the vaccine. People with sickle cell disease often have issues with blood clots. According to Jo Jerrome, chief executive of Thrombosis UK, “Having a previous thrombosis or thrombophilia (sticky blood) is not a risk factor for developing the rare post-Covid-19 vaccine thrombosis and thrombocytopenia.”
The risks of contracting the COVID-19 virus still heavily outweigh the risks of any vaccine side effects.
Is it safe to take the vaccine while taking hydroxyurea?
YES! Hydroxyurea will not interfere with the vaccine response. You can continue taking all of your other sickle cell disease medications (like hydroxyurea) as you usually do.
In one study, for example, all patients with sickle cell disease developed high antibody levels against COVID-19 after receiving 2 doses of the vaccine, despite the fact that 80% of them were taking hydroxyurea at the time.
Do I still need the vaccine if I have contracted COVID-19?
YES. While being infected with COVID-19 can lead to the development of antibodies that protect against re-infection, this response is highly variable: in some individuals, these antibodies occur only at low levels and don’t last. Since vaccination leads to a more consistent and long-lasting response, it is still recommended even for individuals who have previously been infected.
Will the vaccine cause fertility issues?
NO. There is NO evidence to suggest that the vaccine causes fertility issues. In one study of 2000 couples trying to get pregnant, for example, vaccination status did not affect the chances of a successful pregnancy. The same study did find that pregnancy was delayed if the male partner had actually had a recent COVID-19 infection however, other studies have shown harmful effects to both mother and fetus if a woman becomes infected with COVID-19 during her pregnancy. Note: Some women do notice changes in their monthly cycle due to the body’s immune response to the vaccine. This is temporary.
Can I get the vaccine if I am pregnant?
Yes. Other vaccines like the flu shot and Tdap (tetanus, diphtheria, pertussis) are usually recommended during pregnancy. The CDC recommends scheduling the COVID-19 vaccine at least 14 days before or 14 days after other vaccinations. However, every pregnancy is different. If you are pregnant and curious about the COVID-19 vaccine, it is vital to talk to your health provider to determine if receiving the vaccine is right for you, and the best timing to do so.
mRNA vaccines: how do they work?
Two of the vaccines approved for use in Canada are messenger RNA vaccines (called mRNA vaccines): Pfizer and Moderna. The vaccine teaches your cells how to make a protein that will trigger an immune response.
Once triggered, your body makes antibodies. The antibodies fight the infection if you contract the virus.
Government of Canada, Canadian Institutes of Health Research. “The Long Road to MRNA Vaccines – CIHR.” Cihr-Irsc.gc.ca, 28 Apr. 2021, cihr-irsc.gc.ca/e/52424.html.
“How Close Are We to a COVID-19 Vaccine? What Pfizer’s Early Results Mean for Canadians | CBC News.” CBC, www.cbc.ca/news/health/covid-19-vaccine-pfizer-faq-1.5795486.
“Latest Data on COVID-19 Vaccinations by Race/Ethnicity | KFF.” Web.archive.org, 9 July 2021, web.archive.org/web/20210709203754/https:/www.kff.org/coronavirus-covid-19/issue-brief/latest-data-on-covid-19-vaccinations-race-ethnicity/. Accessed 25 Mar. 2022.
Varelas, Christos, et al. “Immune Response of Adult Sickle Cell Disease Patients after COVID-19 Vaccination: The Experience of a Greek Center.” Journal of Clinical Medicine, vol. 11, no. 4, 11 Feb. 2022, p. 937, 10.3390/jcm11040937. Accessed 24 Feb. 2022.
CDC. “Coronavirus Disease 2019 (COVID-19).” Centers for Disease Control and Prevention, 11 Feb. 2020, www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html.
“Study Suggests COVID-19 Vaccines Do Not Reduce Fertility.” National Institutes of Health (NIH), 7 Feb. 2022, www.nih.gov/news-events/nih-research-matters/study-suggests-covid-19-vaccines-do-not-reduce-fertility.
Accessed 25 Mar. 2022.
“Covid Vaccines and Blood Clots: Your Questions Answered.” BBC News, 19 Apr. 2021, www.bbc.com/news/uk-wales-56764182.
“Pregnancy, Breastfeeding, Fertility and the COVID-19 Vaccine – Sunnybrook Hospital.” Sunnybrook.ca, sunnybrook.ca/content/?page=pregnancy-breastfeeding-fertility-covid-19-vaccine.