The Centers for Disease Control (CDC) recommends all eligible individuals be vaccinated against the virus that causes COVID-19. The U.S. Food and Drug Administration (FDA) has issued emergency use authorizations (EUAs) for COVID-19 vaccines to allow for the use of a booster dose as well.
There is currently no evidence that any of the COVID-19 vaccines or boosters cause fertility problems in women or men. Studies have found no differences in pregnancy success rates among women who had:
- Antibodies from COVID-19 vaccines
- Antibodies from a recent COVID-19 infection
- No antibodies, including for patients who used assisted reproductive technology procedures (e.g., in vitro fertilization).
One study of more than 2,000 females aged 21-45 and their partners found that COVID-19 vaccination of either partner did not affect the likelihood of becoming pregnant.
However, getting infected with the virus that causes COVID-19 during pregnancy can result in severe illness and an increased risk of pregnancy complications.
How Safe Are COVID-19 Vaccines for Pregnant Women?
The CDC recommends people trying to get pregnant or planning to become pregnant in the future, as well as their partners, get vaccinated and stay up-to-date with COVID-19 vaccines, including a COVID-19 booster shot.
The mRNA COVID-19 vaccines such as the Pfizer-BioNTech COVID-19 vaccine (Comirnaty) and Moderna COVID-19 vaccine (Spikevax) are preferred over the Janssen (Johnson & Johnson) COVID-19 vaccine for all vaccine-eligible individuals for primary series, primary additional doses (for immunocompromised persons), and booster vaccination.
All three of the COVID-19 vaccines authorized for use in the U.S. have been shown to be highly effective in reducing the risk of severe disease, hospitalization, and death.
How Do COVID-19 Vaccines and Boosters Work?
Vaccines help the body produce immunity to infection by imitating the infecting agent. Vaccines almost never cause serious illness, but instead boost the body’s adaptive immune function to produce T-lymphocytes and antibodies (parts of the immune system that help the body fight germs). Once the simulated infection created by the vaccine goes away, the body has a “memory” of T-lymphocytes and B-lymphocytes that remember how to fight that infection in the future.
Following immunization, it can take several weeks for the body to produce the T-lymphocytes and B-lymphocytes needed to fight infection. So it is possible a person could become infected with COVID-19 just before or just after vaccination because the body has not yet had time to build up its defenses.
The first set of vaccinations helps train the body’s immune system to recognize the virus and fight off the infection. The booster shot helps strengthen or prolong that immune response.
What Are the Side Effects of the COVID-19 Vaccines and Boosters?
About 1-2 days after the COVID-19 vaccine is administered and the body is building its defenses, you may experience mild side effects that can last a few days. This is normal and expected. It is a sign your immune system is responding as it should. Side effects of the booster shot may be similar to those of the primary vaccine series.
Common side effects and reactions to the COVID-19 vaccines and boosters include:
- Injection site reactions (pain, tenderness, redness, swelling)
- Fever
- Chills
- Fatigue/tiredness
- Muscle aches or pains
- Headaches
- Nausea
- Vomiting
Rarely, severe allergic reactions such as anaphylaxis can occur after receiving a vaccine. This type of reaction has only occurred in about 2-5 people per million vaccinated in the U.S. These kinds of allergic reactions usually occur within 30 minutes after vaccination and can be immediately and effectively treated.
People who are allergic to specific ingredients in the current vaccines are advised to avoid that particular vaccine. Those prone to allergic reactions, but who do not have a known allergy to a component of the vaccine, are advised to receive the vaccine in a healthcare facility and to wait 30 minutes (instead of 15) following an injection.
There is a Vaccine Adverse Event Reporting System (VAERS) in place for patients to report unexpected vaccine side effects: https://vaers.hhs.gov/
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html
https://www.cdc.gov/media/releases/2021/p1021-covid-booster.html
https://www.cedars-sinai.org/blog/understanding-vaccine-boosters.html
https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-takes-additional-actions-use-booster-dose-covid-19-vaccines
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/planning-for-pregnancy.html