covid vaccine faq

FREQUENT ASKED QUESTIONS


Is the COVID-19 vaccine safe?

COVID-19 vaccines are safe and effective. COVID-19vaccines were evaluated in tens of thousands of participants in clinical trials. The vaccines met FDA’s rigorous scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization (EUA).Millions of people in the United States have receivedCOVID-19 vaccines, and these vaccines will undergo the most intensive safety monitoring in U.S. history. This monitoring includes using both established and new safety monitoring systems to make sure that COVID-19 vaccines are safe.

Is the vaccine free?

Yes. The COVID-19 vaccines will be available at no cost. 

What are the common misconceptions about the COVID-19 vaccine?

Now that there are authorized and recommended COVID-19 vaccines in the U.S., accurate vaccine information is critical. Here are the facts behind some of the most common vaccine myths:

MYTH: COVID-19vaccines are used to microchip people.
FACT: There is no vaccine microchip, and the vaccine will not track people or gather personal information into a database.

MYTH: You can get COVID-19 from the vaccine.
FACT: None of the COVID-19 vaccines currently in development in the United States use the live virus that causes COVID-19. There are several different types of vaccines in development. However, the goal for each of them 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 area sign that the body is building immunity. Learn more about how COVID-19vaccines work.

MYTH: COVID-19 vaccines will alter my DNA.
FACT: According to the CDC, the first COVID-19 vaccines to reach the market are messenger RNA, or mRNA, vaccines. Messenger RNA vaccines work by instructing cells in the body how to make a protein that triggers an immune response. Injecting messenger RNA into your body will not interact or do anything to the DNA of your cells. Human cells break down and get rid of the messenger RNA soon after they have finished using the instructions.

Can I choose which COVID- 19 vaccine I get?

You should get anyCOVID-19 vaccine that is available when you are eligible. Do not wait for a specific brand. All currently authorized and recommended COVID-19 vaccines are safe and effective, and CDC does not recommend one vaccine over another.

Learn more about your COVID-19 vaccination, including how to find a vaccination location, what to expect at your appointment, and more.

 What are the most common side effects after getting a COVID-19 vaccine?

After getting vaccinated, you might have some side effects, which are normal signs that your body is building protection. Common side effects are pain, redness, and swelling in the arm where you received the shot, as well as tiredness, headache, muscle pain, chills, fever, and nausea throughout the rest of the body. These side effects could affect your ability to do daily activities, but they should go away in a few days. Learn more about what to expect after getting a COVID-19 vaccine.

Related page: Possible Side Effects

How long does protection from a COVID-19 vaccine last?

We don’t know how long protection lasts for those who arevaccinated. What we do know is that COVID-19 has caused very serious illnessand death for a lot of people. If you get COVID-19, you also risk giving it toloved ones who may get very sick. Getting a COVID-19 vaccine is a safer choice.

Experts are working to learn more about both natural immunity and vaccine-induced immunity. CDC will keep the public informed as new evidence becomes available.

If I have an underlying condition, can I get a COVID-19 vaccine?

People with underlying medical conditions can receive a COVID-19 vaccine as long as they have not had an immediate or severe allergic reaction to a COVID-19 vaccine or to any of the ingredients in the vaccine. Learn more about vaccination considerations for people with underlying medical conditions. Vaccination is an important consideration for adults of any age with certain underlying medical conditions because they are at increased risk for severe illness from COVID-19.

How many doses will I need to get?

The number of doses needed depends on which vaccine you receive. To get the most protection:

  • Two Pfizer-BioN Tech vaccine doses should be given 3 weeks (21 days) apart.
  • Two Moderna vaccine doses should be given 1month (28 days) apart.
  • Johnson& Johnsons Jansen (J&J/Janssen)COVID-19 vaccine requires only one dose.


If you receive a vaccine that requires two doses, you should get your second shot as close to the recommended interval as possible. However, your second dose may be given up to 6 weeks (42 days) after the first dose, if necessary.. You should not get the second dose earlier than the recommended interval.

If I have already had COVID-19 and recovered, do I still need the vaccine?

Yes, you should be vaccinated regardless of whether you already had COVID-19. That’s because experts do not yet know how long you are protected from getting sick again after recovering from COVID-19. Even if you have already recovered from COVID-19, it is possible—although rare—that you could be infected with the virus that causes COVID-19 again. Learn more about why getting vaccinated is a safer way to build protection than getting infected.

If you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine. Talk to your doctor if you are unsure what treatments you received or if you have more questions about getting a COVID-19 vaccine.

Experts are still learning more about how long vaccines protect against COVID-19 in real-world conditions. CDC will keep the public informed as new evidence becomes available.

If I am pregnant, can I get a COVID-19 vaccine?

Yes, if you are pregnant, you might choose to be vaccinated. Based on how COVID-19 vaccines work, experts think they are unlikely to pose a specific risk for people who are pregnant. However, there are currently limited data on the safety of COVID-19 vaccines in pregnant people because these vaccines have not been widely studied in pregnant people. Systems are in place to continue to monitor vaccine safety, and so far, they have not identified any specific safety concerns for pregnant people. Clinical trials to evaluate the safety and efficacy of COVID-19 vaccines in pregnant people are underway or planned.

You might want to have a conversation with your healthcare provider to help you decide whether to get vaccinated. While a conversation with your healthcare provider might be helpful, it is not required before to vaccination. Learn more about vaccination considerations for people who are pregnant or breastfeeding.

If you are pregnant and have received a COVID-19 vaccine, we encourage you to enroll in v-safe, CDC’s smartphone-based tool that provides personalized health check-ins after vaccination. A v-safe pregnancy registry has been established to gather information on the health of pregnant people who have received a COVID-19 vaccine.

Can I get COVID-19 between the first and second shot?

According to the FDA, the Pfizer and BioNTech COVID-19 vaccine starts working within about two weeks of the first dose. While potential vaccines have very high protection rates against infection from COVID-19, it is possible that the vaccine will be ineffective for you. You will still need to wear a mask and practice good hand hygiene and social distancing following a vaccination.

Does the vaccine make me immune to the virus or just reduce the symptoms?

COVID-19vaccines are being carefully evaluated in clinical trials and are authorized or approved by the FDA only if they make it substantially less likely that you’ll get COVID-19. The Pfizer and Moderna vaccines were shown to prevent COVID-19 in people compared to those who received a placebo. Experts believe that getting aCOVID-19 vaccine may help keep you from getting seriously ill even if you are exposed to COVID-19 by boosting your immune response should you be exposed toCOVID-19 in the future. Getting vaccinated may also protect people around you, particularly people at increased risk for severe illness from COVID-19.

Will I still need to wear a mask if I have received both doses of the vaccine?

Yes. Wearing a mask and practicing social distancing is still important after receiving the vaccine. There will be limited doses available initially, and because people will be vaccinated in waves, it will take time to vaccinate enough of the population to stop the spread of COVID-19. Additionally, it is not known how long immunity will last. Furthermore, infection after a receiving a vaccine may still be possible, although it is likely that it would be less severe, such as a mild or asymptomatic infection. Others can still be infected in this scenario, necessitating the continued use of masks.

How was the vaccine developed so quickly?

There are many factors that combined to allow theCOVID-19 vaccine to be developed quickly and safely:

  • Researchers got a head start on developing a vaccine because the virus that causes COVID-19 is similar to other existing viruses. 
  • Research about the new virus was shared almost immediately with scientists all over the world, which allowed work to begin on a vaccine right away.
  • Some researchers were able to run phase one and two trials at the same time.
  • The studies on COVID-19 included a larger number of people than other recent vaccine trials, meaning there were a larger number of people in the trials over a shorter period of time.
  • The federal government allowed manufacturing of the most promising vaccines to begin while the studies were ongoing. That means that when it is authorized it can be offered to the public almost immediately.


It’s important to note that all vaccine developers are required to go through each stage of the development process and meet all safety and efficacy (how well something works) standards. Learn about the many steps in the typical vaccine testing and approval process.

Who is eligible for vaccines?

Maryland is now in Phase 3 of our phased distribution plan. Eligible groups now include:

  • All licensed, registered and certified health care providers
  • Front line hospital staff
  • Nursing home residents and staff
  • Individuals with intellectual and developmental disabilities
  • Assisted living, independent living, behavioral health and developmentally disabled group homes, and other congregate facilities
  • Law enforcement and firefighters, EMS
  • Education staff, including K-12 teachers, support staff and daycare providers
  • Correctional health care staff and officers
  • Public safety workers not covered in Phase 1A
  • Health care workers not covered in Phase 1A, including but not limited to lab services, public health, vaccine manufacturing and other health care professions
  • Front line judiciary staff
  • Continuity of government
  • Food/agriculture production, critical manufacturing, U.S. Postal Service, public mass transit, grocery store employees
  • Veterinarians and support staff
  • Clergy and other essential support for houses of worship
  •  Individuals who are currently receiving hospital-based treatment, including in hospital outpatient centers, AND diagnosed with at least one of the following conditions:
    • Cancer patients who are currently in active treatment
    • End-stage renal disease patients requiring hemodialysis
    • Chronic Obstructive Pulmonary Disease (COPD)
    • Solid organ transplant recipients
    • Sickle cell disease patients
    • Diabetic patients (Type 1 and Type 2)
  • Individuals who are diagnosed with these medical conditions but are not currently receiving hospital-based treatment, including in hospital outpatient centers, will be eligible to receive the vaccine in Maryland’s Phase 2 COVID-19 vaccine distribution.
  • Marylanders ages 16+ with underlying medical conditions that increase the risk for severe COVID-19 illness
  • Marylanders ages 16+ with disabilities who are receiving SSI or SSDI benefits, Maryland Medicaid EID individuals, Maryland Medicaid REM recipients, and Marylanders receiving TDAP benefits
  • Marylanders receiving long term services and supports through the state’s Medicaid waiver and state plan services (learn more)
  • Adults 55 and older
  • Essential workers in critical industries, including construction workers, food services, utilities, transportation, financial services, IT and other infrastructure
  • All Marylanders 16 and older

What is the difference between registering for a vaccine and a vaccine appointment?

Registering is not the same as scheduling a vaccination appointment. You fill out a registration form to request a vaccination appointment. Completing this form does not create an appointment. Once an appointment is available, you will be contacted. The time between submitting the registration form and getting notification to schedule an appointment varies by vaccination site and provider depending on the number of eligible people who register and the overall vaccine supply.