COVID-19 Vaccine Information

The Baltimore City Health Department offers free COVID-19 vaccinations to residents 6 months and older

Anyone can now receive a bivalent COVID-19 vaccine - the most updated formulation - regardless of previous vaccination status. Learn more about the CDC's most recent COVID-19 vaccine announcement on April 19th 2023 here.

See all upcoming walk-up vaccination clinics
Register for a vaccination appointment

Do you need a vaccination at home?
You can register for an appointment or call (443)-984-8650 to schedule an individual who needs to receive the vaccine at home.

Baltimore City Call Center line (443)-984-8650
For more information

Are you a Medical Provider? Click this link to sign up for the Baltimore City Health Department's COVAX provider newsletter!

If you have "Questions or Suggestions" about this website or need more information about COVID-19 vaccines please Email us by clicking here. 

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Side Effects
Frequently Asked Questions
How Do The Vaccines Work?
Differences between the Vaccines
Additional Information


  • In December 2020, pharmaceutical companies Pfizer and Moderna were granted Emergency Use Authorizations (EUAs) by the Federal Drug Administration (FDA) for COVID-19 vaccines.
  • In February 2021, Johnson and Johnson were granted an Emergency Use Authorization (EUA). 
  • The approval of an Emergency Use Authorization by the FDA  means the vaccine has been tested and is considered safe and effective for the general public to take.

How do they work?

  • Both the Pfizer and Moderna vaccines are known as mRNA vaccines. 
    • mRNA vaccines help our body develop immunity against COVID-19. Immunity means that your body will quickly recognize the virus that causes COVID-19 and will protect you from getting sick. 
      • mRNA vaccines do not change your DNA 
      • mRNA vaccines do not cause disease
      • mRNA vaccines are not weakened the COVID-19 virus

  • The Johnson & Johnson vaccine is a viral vector vaccine 
    • It is made from an inactivated adenovirus, the virus that causes the common cold, and contains a piece of DNA that instructs the body to make the COVID-19 spike protein.
      • It does not contain live coronavirus and will not get you infected with COVID-19.

What are the differences between the Moderna Vaccine, Pfizer Vaccine, and the Johnson and Johnson Vaccine?

  • The Johnson and Johnson vaccine is a single-dose vaccine. Pfizer and Moderna vaccines require 2 separate doses to be fully protected from COVID-19. For the Pfizer vaccine, the doses are 21 days apart, and for the Moderna vaccine, the doses are 28 days apart.
  • The Pfizer Vaccine is approved for those aged 16 and up, while both the Moderna and Johnson and Johnson vaccines are approved for adults aged 18 and up.
  • All of the current vaccines reduce the risk of severe illness. 

Side Effects of the COVID-19 Vaccines

The most commonly reported side effects were pain at the injection site, headache, fatigue, muscle aches, and nausea. Most of these side effects occurred within 1-2 days following vaccination and were mild to moderate in severity and lasted 1-2 days.

Some of those receiving the Moderna and Pfizer vaccines also reported fever, joint pain, and lymph node swelling, in addition to the side effects listed above. 

Frequently Asked Questions About the COVID-19 Vaccines

We've turned these Frequently Asked Questions on our Infographics Page. The Maryland Health Department has created a frequently asked questions website that we encourage residents to visit for additional information. Some of the most frequently asked questions we're received are directly answered below. Check back frequently for updates! 

What is the COVID-19 Vaccine?

  • The COVID-19 vaccine protects you from getting sick with COVID-19 and reduces your chances of developing severe illness. 
  • The vaccine comes in either one or two shots.
  • The Johnson and Johnson vaccine is a single-dose vaccine, while the Moderna and Pfizer vaccines are two-dose vaccines. 
    • In the case of Moderna and Pfizer, after getting your first shot, you will take the second shot in 3-4 weeks, depending on which vaccine you receive. 
  • You need to wait 2 weeks after your shot (or second shot in the case of Moderna/Pfizer) to be fully protected from COVID-19.

How Does the Vaccine Work?

  • The Moderna and Pfizer vaccine use mRNA, which teaches your body to safely build protection against COVID-19.
    • mRNA does not change your genes (DNA) because the mRNA cannot affect your DNA
  • The Johnson & Johnson vaccine is a viral vector vaccine. It is made from an inactivated adenovirus, the virus that causes the common cold, and contains a piece of DNA that instructs the body to make the COVID-19 spike protein.
    • It does not contain live coronavirus and will not get you infected with COVID-19.

Is the COVID-19 Vaccine Safe?

  • Yes! The COVID-19 vaccines have been tested in trials and the data shows that COVID-19 vaccines are safe and that they work. People that get the vaccine are asked to report any side effects, so we know it continues to be safe.

How can we know it is safe and works if it was produced so fast?

  • Scientists have been working with mRNA vaccines for more than a decade and were able to quickly apply them to the COVID-19 virus. The extra money from the federal government allowed them to work faster, but without skipping any steps. Because the disease has been spreading fast, they were able to show the vaccine worked much sooner than it would for other vaccines.

Can a COVID-19 vaccine make you sick with COVID-19?

  • No! COVID-19 vaccines do not contain the virus. This means the vaccine cannot give you COVID-19.
  • The vaccine teaches our body to recognize and fight the COVID-19 virus.
  • With the shots, you may have mild symptoms, such as fever. These symptoms show that your body is building protection.

Who Should Get the Vaccine?

  • Everyone should get vaccinated, including those with health problems and older adults.
  • Even if you already had COVID-19, you should still get vaccinated to protect yourself and others.

What about Social Distancing?

  • Even if you are vaccinated, please continue to wear your mask, wash your hands often, and stay at least 6 feet away from other people you do not live with.
  • Your efforts will help keep everyone safe!

Why is it important to get the COVID-19 vaccine?

  • The vaccine reduces your chances of getting sick from COVID-19 and may reduce your chance of spreading it to others

What if I can’t afford the vaccine?

  • The vaccine is free! 
  • Some online appointment systems may ask you for your insurance information, but even if you have no insurance, you can get the vaccine.

COVID-19 vaccines will not give you COVID-19 

  • There are several different types of vaccines in development, however, none of the COVID-19 vaccines available or currently in development in the United States use the live virus that causes COVID-19. The goal of each of these vaccines is to teach our immune systems how to recognize and fight the virus that causes COVID-19. Sometimes this process can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.  

People who have been infected with COVID-19 will still benefit from getting the COVID-19 vaccine 

  • At this time, we do not know how long someone is protected from getting sick again after recovering from COVID-19. The immunity someone gains from having an infection, called natural immunity, varies from person to person. Some early evidence suggests natural immunity may not last very long. We don’t know exactly how long immunity produced by a vaccination lasts but there is strong evidence to support that immunity due to vaccination lasts longer than natural immunity. The vaccine provides longer and stronger immunity 

Getting vaccinated can help prevent getting sick with COVID-19 

  • While many people with COVID-19 have only a mild illness, others may develop a more severe illness or even die. There is no way to know how COVID-19 will affect you, even if you are not at increased risk of severe complications. If you get sick, you also may spread the disease to friends, family, and others around you while you are sick. COVID-19 vaccination helps protect you by creating an antibody response without having to experience sickness. 

Until we’ve reached herd immunity, you still need to wear a mask, avoid large indoor gatherings, and be physically distant even after getting the vaccine.  

  • Even though the vaccine is between 94 and 95% effective at reducing severe illness, about 1 in 20 people who receive it will not become immune.  At this time, it is also unclear whether having immunity protects you from carrying the virus and passing it to others. Until a significant portion of the population becomes immune (referred to as “herd immunity”), the precautions must be carefully followed. This will likely take months or even years depending on vaccine uptake. 

Receiving an mRNA vaccine will not alter your DNA 

  • mRNA stands for messenger ribonucleic acid and can most easily be described as instructions for how to make a protein or even just a piece of protein. mRNA is not able to alter or modify a person’s genetic makeup (DNA). The mRNA from a COVID-19 vaccine never enters the nucleus of the cell, which is where our DNA is kept. This means the mRNA does not affect or interact with our DNA in any way. Instead, COVID-19 vaccines that use mRNA work with the body’s natural defenses to safely develop protection (immunity) to disease. 

For questions about the COVID-19 Vaccines specifically focused on expecting and new mothers, click here.

Additional Information