Is the COVID-19 vaccine safe?

The COVID-19 vaccines have gone through the same testing and analysis that is used for all vaccines to make sure they’re safe and effective.

Learn about why the COVID-19 vaccines are safe, how effective they are, and the extensive work that was done to get them ready for safe use as soon as possible:

Are the COVID-19 vaccines safe and effective?

Like other drugs and biologics, vaccines released in the U.S. must go through multiple phases of rigorous testing, analysis, and review as they are developed. The U.S. Food and Drug Administration (FDA) closely monitors the vaccine development process and testing results for efficacy and safety. As part of the FDA’s formal process to determine if the vaccine is authorized for public use, it also seeks a recommendation from a multidisciplinary team of experts consisting of independent medical officers, microbiologists, chemists, biostatisticians, and other health experts. If approved, the FDA continues to oversee the vaccine and its manufacturing to ensure ongoing safety.

Although the speed of the COVID-19 development is faster than typical, COVID-19 vaccines are still required to go through the proper testing and analysis to make sure they are safe—no step in the process has been skipped.

Can any of the vaccines give me COVID-19?

None of these vaccines contain the virus, so they can’t give you COVID-19. These vaccines contain genetic instructions that allow your own cells to make one of the virus proteins. Your immune system reacts to this protein to make antibodies and other immune cells that can recognize and fight COVID-19 if you do get exposed.

Are you giving the Johnson & Johnson (Janssen) COVID-19 vaccine?

On Friday, April 23, 2021, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) lifted the temporary pause of the Johnson & Johnson (Janssen) COVID-19 vaccine, allowing vaccine providers to resume administration of this vaccine.

UI Health Care is following guidance from the Food and Drug Administration and the Centers for Disease Control and Prevention and is resuming administration of the Johnson & Johnson (Janssen) COVID-19 vaccine.

Should people with certain pre-existing conditions receive a different COVID-19 vaccine instead of the Johnson & Johnson (Janssen) vaccine?

A review of all available data at this time shows that the Johnson & Johnson (Janssen) COVID-19 vaccine’s benefits outweigh its risks for those recommended to receive it. However, women younger than 50 years old should be aware of the rare but increased risk of blood clots after vaccination and that other COVID-19 vaccines have not shown this same risk.

Why did the FDA and CDC pause administration of the Johnson & Johnson (Janssen) vaccine?

On Tuesday, April 13, 2021, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) paused administration of the Johnson & Johnson (Janssen) COVID-19 vaccine out of an abundance of caution.

This pause was a result of six women from the United States who experienced blood clots after receiving this vaccine. While these reports are rare, with more than 6.8 million doses of this vaccine administered in the United States with mild or no side effects, pausing the administration of this vaccine allowed the CDC to communicate with health care providers and re-emphasize the importance of reporting severe events in people who have received this vaccine, as well as provide guidance on how to report such events. The pause also gave experts time to carefully review all available data and conduct a risk-benefit analysis around the continued use of this vaccine.

On Friday, April 23, 2021, the CDC and FDA recommended that use of the Johnson & Johnson (Janssen) COVID-19 vaccine resume in the United States. 

Detecting these rare adverse events tells us that the systems in place to monitor the safety of these vaccines are working. The thrombosis with thrombocytopenia syndrome (TTS) reports were detected early, and the pause reflected the federal government’s commitment to transparency and safety as the CDC and FDA gathered and reviewed additional data. COVID-19 vaccines have undergone and will continue to undergo the most intensive safety monitoring in U.S. history.

Does an mRNA vaccine change my DNA or genetic code?

No. Both the Pfizer-BioNTech (Comiranty) and the Moderna vaccines are messenger RNA (mRNA) vaccines. They do not insert themselves in the genome, which is made of DNA.

Learn more about mRNA vaccines.

What are the common side effects of receiving a COVID-19 vaccine?

Early indications are that mild to moderate flu-like side effects might occur, such as arm pain, headache, fatigue, fever, or chills, lasting up to 48 hours. This is your body creating a response to the vaccine and is normal.

Has the COVID-19 vaccine been rushed in comparison to other vaccines?

Although the speed of the COVID-19 development is faster than typical, COVID-19 vaccines are still required to go through the proper testing and analysis to make sure they are safe—no step in the process has been skipped. However, the federal government funded advance production of some of the more promising vaccines so at least a limited supply became available quickly after Food and Drug Administration (FDA) approval.

What do we know about the long-term side effects of the COVID-19 vaccines?

Researcher and infectious disease expert Pat Winokur, MD, provides insight about the long-term side effects in this Vaxx Facts video:

Can pregnant women receive the COVID-19 vaccine?

Pregnant women were not included in the vaccine trials for the current available vaccines. However, based on the Society for Maternal Fetal Medicine recommendations, UI Health Care supports that pregnant women are eligible to receive the vaccine and should discuss this with their obstetrician.

Read more from our providers

Last reviewed: 
August 2021

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