Frequently Asked Questions
Getting Your Vaccine
Am I required to get vaccinated for work?
An employer may require that their workers be vaccinated. Check directly with your employer to see if they have any vaccination requirements or rules that apply to you.
How many doses of COVID-19 vaccine will I need to get to complete my primary series?
The number of vaccine doses you need to complete your primary series depends on which vaccine you receive.
- Two doses of Pfizer-BioNTech vaccine 3–8* weeks apart, or
- Two doses of Moderna vaccine 4–8* weeks apart, or
- One dose of Johnson & Johnson’s Janssen (J&J/Janssen) vaccine.
*Talk to your healthcare or vaccine provider about the timing for the second dose in your primary series. You should not get the second dose early.
People who are moderately or severely immunocompromised may have a different immune response following COVID-19 vaccination. Please see specific COVID-19 vaccination guidance for people who are moderately or severely immunocompromised.
If I didn’t get my second dose of a 2-dose COVID-19 vaccine within the recommended time, do I need to start over?
No. If you receive your second dose of a COVID-19 vaccine at any time after the recommended date, you do not have to restart the vaccine series. This guidance might be updated as more information becomes available.
Learn more about staying up to date with your COVID-19 vaccines.
How long does protection from a COVID-19 vaccine last?
Scientists are monitoring how long COVID-19 vaccine protection lasts. COVID-19 vaccines work well to prevent severe illness, hospitalization, and death. However, public health experts are seeing decreases in the protection COVID-19 vaccines provide over time, especially for certain groups of people. Due to this, CDC recommends that everyone ages 12 and older get a booster for the best protection against COVID-19. Learn more about COVID-19 booster recommendations, including recommendations for people who are moderately or severely immunocompromised.
CDC continues to review evidence and updates guidance as new information becomes available.
Do COVID-19 vaccines affect your menstrual cycle (period)?
Results from recent research studies show that people who menstruate may observe small, temporary changes in menstruation after COVID-19 vaccination, including:
- Longer duration of menstrual periods
- Shorter intervals between periods
- Heavier bleeding than usual
Despite these temporary changes in menstruation, there is no evidence that COVID-19 vaccines cause fertility problems.
Learn more about COVID-19 vaccination for people who would like to have a baby.
Are COVID-19 vaccines safe even though the vaccines were developed rapidly?
Although COVID-19 vaccines were developed quickly, research and development on vaccines like these have been underway for decades. All vaccine development steps were taken to ensure COVID-19 vaccine safety and effectiveness, including:
- Clinical Trials – All vaccines in the United States must go through three phases of clinical trials to ensure they are safe and effective. The phases overlapped to speed up the process, but all phases were completed.
- Authorization or Approval – Before vaccines are available to people, the U.S. Food and Drug Administration (FDA) reviews data from clinical trials. FDA has determined three COVID-19 vaccines meet FDA’s standards and has granted those vaccines Emergency Use Authorizations (EUAs)external icon or full FDA approval.
- Tracking Safety Using Vaccine Monitoring Systems – Like every other vaccine approved for use in the United States, COVID-19 vaccines continue to be monitored for safety and effectiveness. Hundreds of millions of people in the United States have safely received COVID-19 vaccines. CDC and FDA continue to provide updated information on the safety of U.S. authorized or approved COVID-19 vaccines using data from several monitoring systems.
Learn more about developing COVID-19 vaccines.
What are the ingredients in COVID-19 vaccines?
Vaccine ingredients vary by manufacturer. None of the vaccines contain eggs, gelatin, latex, or preservatives. All COVID-19 vaccines are free from metals, such as iron, nickel, cobalt, lithium, and rare earth alloys. They are also free from manufactured products such as microelectronics, electrodes, carbon nanotubes, and nanowire semiconductors. None of the COVID-19 vaccines authorized or approved in the United States contain any live virus.
To learn more about the ingredients in authorized or approved COVID-19 vaccines, see
- Pfizer-BioNTech COVID-19 Vaccine Overview and Safety
- Moderna COVID-19 Vaccine Overview and Safety
- Johnson & Johnson’s Janssen COVID-19 Vaccine Overview and Safety
- Ingredients Included in COVID-19 Vaccines
If I am pregnant or planning to become pregnant, can I get a COVID-19 vaccine?
Yes, COVID-19 vaccination is recommended for people who are pregnant, breastfeeding, or trying to get pregnant now, as well as people who might become pregnant in the future. People with COVID-19 during pregnancy are more likely to deliver a preterm (earlier than 37 weeks) or stillborn infant and may also be more likely to have other pregnancy complications.
COVID-19 vaccination during pregnancy helps
- Prevent severe illness and death in people who are pregnant
- Protect babies younger than 6 months old from hospitalization caused by COVID-19
Learn more about vaccination considerations and the safety and effectiveness of COVID-19 vaccinations 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 system 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.
Why should my children and teens get vaccinated against COVID-19?
COVID-19 can make children and teens very sick and sometimes requires treatment in a hospital. Getting eligible children and teens vaccinated against COVID-19 can help keep them from getting really sick if they do get COVID-19, including protecting them from short and long-term complications and hospitalization. Vaccinating children can also help keep them in school or daycare and safely participating in sports, playdates, and other group activities.
The benefits of COVID-19 vaccination outweigh the known and potential risks. CDC recommends everyone ages 5 years and older get vaccinated against COVID-19. Everyone ages 12 years and older should also get a COVID-19 booster shot.
Preparing for Your Vaccine
Why should I get vaccinated if I might get COVID-19 anyway?
COVID-19 vaccination significantly lowers your risk of severe illness, hospitalization, and death if you get infected. Compared to people who are up to date with their COVID-19 vaccinations, unvaccinated people are more likely to get COVID-19, much more likely to be hospitalized with COVID-19, and much more likely to die from COVID-19.
Like all vaccines, COVID-19 vaccines are not 100% effective at preventing infection. Some people who are up to date with their COVID-19 vaccinations will get COVID-19 breakthrough infection. However, staying up to date with your COVID-19 vaccinations means that you are less likely to have a breakthrough infection and, if you do get sick, you are less likely to get severely ill or die. Staying up to date with COVID-19 vaccination also means you are less likely to spread the disease to others and increases your protection against new variants of SARS-CoV-2, the virus that causes COVID-19.
Do I need to wait after getting a flu vaccine or another vaccine before getting a COVID-19 vaccine?
There is no recommended waiting period between getting a COVID-19 vaccine and other vaccines. You can get a COVID-19 vaccine and other vaccines, including a flu vaccine, at the same visit. Experience with other vaccines has shown that the way our bodies develop protection, known as an immune response, and possible side effects after getting vaccinated are generally the same when given alone or with other vaccines.
If I already had COVID-19 and recovered, do I still need to get a COVID-19 vaccine?
You should get a COVID-19 vaccine even if you already had COVID-19.
Getting a COVID-19 vaccine after you recover from COVID-19 infection provides added protection against COVID-19. People who already had COVID-19 and do not get vaccinated after their recovery are more likely to get COVID-19 again than those who get vaccinated after their recovery.
Learn more about the benefits of getting a COVID-19 vaccine.
Can I get vaccinated against COVID-19 while I am currently sick with COVID-19?
No. People with COVID-19 should wait to be vaccinated until after they complete their isolation period. People who have symptoms will end isolation at a different time than people who do not have symptoms. This also applies to people who have been vaccinated but get COVID-19 before getting any additional or booster doses.
People who have had a known COVID-19 exposure should not seek vaccination until their quarantine period has ended to avoid potentially exposing healthcare personnel and others during the vaccination visit. This recommendation to wait also applies to people with a known COVID-19 exposure who have received their first dose and are in need of additional or booster doses.
Can I choose which COVID-19 vaccine I get?
Yes, depending on your age, you can choose which COVID-19 vaccine to get. For adults ages 18 years and older, the mRNA COVID-19 vaccines (Pfizer-BioNTech or Moderna) are preferred over Johnson & Johnson’s Janssen (J&J/Janssen) COVID-19 vaccine. You may get J&J/Janssen COVID-19 vaccine in some situations.
Currently, Pfizer-BioNTech COVID-19 vaccine is the only COVID-19 vaccine available to children ages 5 through 17 years old.
Learn more about your COVID-19 vaccination, including how to find a vaccination location, what to expect at your appointment, and more.
After Your Vaccine
How can I get a new CDC COVID-19 Vaccination card?
If you have lost your CDC COVID-19 Vaccination card or don’t have a copy of it, contact your vaccination provider directly to request a new vaccination card. They may be able to reissue a CDC COVID-19 Vaccination card.
- If you cannot contact your vaccination provider directly or your vaccination provider cannot reissue a CDC COVID-19 Vaccination card, contact your state health department’s immunization information system (IIS). Your state’s IIS cannot issue you a vaccination card, but they can provide a digital or paper copy of your full vaccination record, including your COVID-19 vaccinations.
- If you need another COVID-19 vaccine dose and are unable to get a copy of your vaccination card or vaccination record, talk to a vaccination provider to learn about your possible options.
- Some vaccination providers and health departments may offer you access to a QR code or digital copy of your CDC COVID-19 Vaccination card in addition to giving you a physical card. Contact your vaccination provider or local health department to learn if you can get a digital copy of your card.
CDC does not provide the white CDC COVID-19 Vaccination card to people and does not maintain vaccination records. CDC distributes the white CDC COVID-19 Vaccination cards to vaccination providers and only a vaccination provider can give you this card.
Do I need to wear a mask and avoid close contact with others if I am vaccinated?
Generally, if you are up to date on your COVID-19 vaccinations, you do not need to wear a mask in outdoor settings. Check your local COVID-19 Community Level for recommendations on when to wear a mask indoors and additional precautions you can take to protect yourself from COVID-19. If you are immunocompromised or more likely to get very sick from COVID-19, learn more about how to protect yourself.
Should I wear a mask if I have a weak immune system?
If you have a condition or are taking medications that weaken your immune system, your immune response to COVID-19 vaccination may not be as strong as in people who are not immunocompromised. Check your county’s COVID-19 Community Level for recommendations on whether you should wear a mask and additional actions you can take to protect yourself from COVID-19. Keep in mind that you may choose to wear a mask at any time based on your own level of comfort and personal risk.
Learn more about COVID-19 vaccinations for people who are moderately or severely immunocompromised.
I was vaccinated in another country. How do I transfer my proof of vaccination from that country to get a proof of vaccination card in the United States?
Am I considered fully vaccinated if I was vaccinated in another country?
It depends on a number of factors. Learn more about COVID-19 Vaccines for People Who Were Vaccinated Abroad.