How do COVID-19 vaccines work?

A vaccine is medicine used to boost your body’s immune system to prevent a disease. COVID-19 vaccines give you immunity to the virus that causes COVID-19.

Eligible for the vaccine? UI Health Care will contact you when your dose is ready

Based on guidance from the Centers for Disease Control and Prevention and the Iowa Department of Public Health, we are working on plans to begin vaccinating our eligible patients in Phase 1b who are age 75 and older.

We are not taking appointments for vaccinations. If you are a UI Health Care patient and eligible for the vaccine, you will be contacted through your MyChart account or by phone. We do not have a waitlist for the vaccine.

Learn about what vaccines do, how they do it, and how the authorized vaccines prevent COVID-19.

What are the vaccines against COVID-19?

There are two vaccines for COVID-19 currently authorized for emergency use by the U.S. Food and Drug Administration: the Pfizer-BioNTech vaccine and the Moderna vaccine.

The two vaccines are very similar. Both are mRNA vaccines. Both require two doses. Both provide almost 95% protection against COVID-19.

What is emergency use authorization (EUA)?

In certain types of emergencies, the Food and Drug Administration (FDA) can issue an emergency use authorization (EUA) to provide more timely access to drugs, diagnostic tests, or other critical medical products that may help during an emergency, like the COVID-19 pandemic.

Learn more about EUAs in this video

Do I have to receive the vaccine?

You are encouraged to receive the vaccine as soon as you are eligible to provide protection for yourself and others, but receiving the vaccine is not required.

What are the common side effects of the 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.

If I get the vaccine, does it provide protection to my children?

We anticipate that this will be the case, though we are waiting for the data from studies to prove that the vaccine reduces spread of disease from person to person.

Do you gain some immunity to the virus after the first vaccination, or only after the second vaccination?

We believe you gain some immunity after the first dose. Full immunity is achieved approximately 7 days after the second dose, according to clinical studies.

Last reviewed: 
February 2021

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