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Frequently Asked Questions

Updated 05/09/22

This FAQ provides information on the three FDA-authorized/approved COVID-19 vaccines that are available in the US. These vaccines are made by Moderna, Pfizer, and Janssen/Johnson & Johnson (J&J). Click here to view a print version of each COVID-19 Vaccine FAQ by topic. Also available in additional languages.”

COVID-19 vaccines protect people from getting very sick from COVID-19 and ending up in the hospital or dying. They also reduce the risk of becoming chronically ill from COVID-19 (such as long-COVID), and from missing work and school.

In addition, getting vaccinated lowers the risk of giving COVID-19 to other people. This is especially helpful in protecting people at higher risk of getting very sick.

It is recommended that people who've had COVID-19 in the past still get the vaccine to strengthen their immunity and to reduce their risk of getting hospitalized with COVID-19.

Updated 5/03/22

The COVID-19 vaccines work very well at protecting against severe illness, hospitalization, and death from COVID-19. 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 sick with COVID-19. But if you stay up to date with your vaccinations and you do get infected, you are less likely to get sick and, if you do get sick, you are less likely to get severely ill or die. Staying up to date with COVID-19 vaccinations reduces the chance of spreading the disease to others and increases your protection against new variants of SARS-CoV-2, the virus that causes COVID-19.

As the science and the virus evolves, so do vaccine recommendations. Scientists and medical experts continue to closely watch for signs of decreased immunity in people of different ages and with different risk factors. They also look at how well the vaccines protect against new variants of the virus.

Updated 5/03/22

Three COVID-19 vaccines are available in the US. They are made by Janssen/Johnson & Johnson (J&J), Pfizer-BioNTech (brand name Comirnaty), and Moderna (brand name Spikevax). All three vaccines can be given to people ages 18+. In addition, the Pfizer vaccine is authorized for children age 5+.

The CDC now recommends the Pfizer and Moderna COVID-19 vaccines over the J&J vaccine. Pfizer and Moderna are preferred for all vaccine doses because they offer better protection against COVID-19 than the J&J vaccine. In addition, the potential risks from the J&J vaccine, while rare, are greater than those with the Pfizer and Moderna vaccines.

The J&J vaccine is still available for:

To learn more, visit the CDC Stay Up to Date with Your COVID-19 Vaccines webpage.

Updated 5/03/22


Being up to date with your COVID-19 vaccines means that:

  • You have received all the recommended primary series doses, and you have received one booster when it is due –or–
  • You have received all the recommended primary series doses, and you are not yet due for a booster dose.

When people are up to date with their COVID-19 vaccines, they get the best protection from severe COVID-19 illness.

Check the COVID-19 Vaccine Schedule at for information on all recommended primary and booster doses. For more details, see the CDC webpage, Stay Up to Date with Your COVID-19 Vaccines.

Posted 5/02/22

You are considered fully vaccinated two weeks after receiving all the recommended primary series doses:

  • You got a single dose of Johnson & Johnson (J&J)/Janssen COVID-19 vaccine, or
  • You got a second dose of a Pfizer (COMIRNATY) or Moderna (SPIKEVAX) COVID-19 vaccine, or
  • You got all the recommended doses of active COVID-19 vaccine (not placebo) in a clinical trial with confirmed efficacy.

If you were vaccinated outside the US or with mix-and-match vaccines, see the sections below.

Updated 5/02/22

Some situations require that a person be fully vaccinated. For example, being fully vaccinated may be a requirement for international travel, employment, to attend school, or to enter some venues.

Being up to date with vaccines may not currently be required in most situations. But it gives you the best protection against COVID-19.

Updated 5/02/22
  • If you got a full series of a COVID-19 vaccine that is approved or authorized by the FDA or listed by the WHO:
    • You are considered fully vaccinated two weeks after your final dose.
  • If you got two doses of different COVID-19 vaccines that are both approved or authorized by the FDA or listed by the WHO as a 2-dose series:
    • You are considered fully vaccinated two weeks after your final dose. Note: CDC does not recommend that people mix-and match-COVID-19 vaccines for the primary series.
  • If you got some or all of a series of a COVID-19 vaccine that is NOT approved or authorized by the FDA or listed by the WHO:
    • You are not considered to be fully vaccinated by US authorities.
    • If you want to be considered fully vaccinated in the US, you will need to complete a new series of a vaccine that is authorized or approved by the FDA or listed by the WHO. You should wait at least 28 days after your last vaccine dose before starting an FDA authorized/approved COVID-19 vaccine primary series.
  • If you started a series of a COVID-19 vaccine that is listed by the WHO but is not available in the US:
    • You are not considered to be fully vaccinated by US authorities.
    • If you are already in the US and want to be considered fully vaccinated, you must get a single dose of an mRNA vaccine (Pfizer or Moderna COVID-19 vaccine) to be considered fully vaccinated. You should wait at least 28 days after getting the first WHO-listed COVID-19 vaccine dose to complete your primary series. Note: Children age 5-17 can only receive a Pfizer COVID-19 vaccine.

See People who received COVID-19 vaccine outside the United States for more details.

Updated 5/02/22

The CDC does not recommend that people mix-and-match COVID-19 vaccines for the primary series. But if you mix-and-match, you are considered fully vaccinated 2 weeks after getting the second dose of any combination of vaccines that are approved or authorized by the FDA or listed by the WHO as a 2-dose series. There must be at least 17 days between dose 1 and dose 2 for you to be considered fully vaccinated (21 days with a 4-day grace period).

See the CDC webpage Non-U.S. Citizen, Non-U.S. Immigrants: Travel to and from the United States to learn more.

Updated 5/02/22

Booster Doses

The CDC recommends that everyone age 12 and older get a booster dose for the best protection against COVID-19. In addition, some people at higher risk can choose to get a 2nd booster. (See Who can get a 2nd booster? below). Booster doses are not currently authorized for children 5-11 years of age.

Getting a COVID-19 vaccine booster is important because it strengthens your immunity. This gives you better protection from getting seriously ill, being hospitalized, and even dying.

Updated 5/02/22
  • If you are age 12 and over, you are eligible for a booster dose:
    • 2 months after a single dose of Johnson & Johnson (J&J) vaccine, or
    • 5 months after the 2nd dose of Moderna or Pfizer vaccine.
    The booster dose may be any COVID-19 vaccine, but Pfizer or Moderna are preferred. Children ages 12-17 can only get a Pfizer booster.
  • If you are moderately or severely immunocompromised, you should get your booster dose sooner. See the CDC webpage COVID-19 Vaccines for Moderately or Severely Immunocompromised People to learn more.
  • If you received a vaccine series outside the US, see the CDC webpage COVID-19 Vaccines for People Vaccinated Outside the United States to see when you are eligible for a booster dose.
Updated 5/02/22

The following people are eligible to get a 2nd COVID-19 booster if it has been at least 4 months since their 1st booster:

Please ask your doctor if you have questions about whether you should get a second booster dose.

Updated 5/02/22

If you are in one of the groups who can get a 2nd booster, you can choose to get it right now or to wait. Consider your situation and the risks and benefits. Your doctor can help you review your options. You do not need a 2nd booster dose to be considered up to date on your COVID-19 vaccines at this time.

Certain factors can make it more likely that you could get very sick from COVID-19. If you are eligible for a second booster, it may be helpful to get it now if you are (or if someone you live with is):

  • Moderately or severely immunocompromised
  • More likely to get very sick from COVID-19
  • More likely to be exposed to COVID-19 through your job, where you live, or other factors (such as traveling often or participating in large gatherings)
  • In an area with substantial to high COVID-19 transmission levels
  • If someone you live with is unvaccinated

You may consider waiting to get a 2nd booster if you:

  • Had COVID-19 within the past 3 months
  • Are healthy and have limited exposures to others

See the CDC webpage Getting a 2nd COVID-19 Vaccine Booster for more information. Talk to your doctor if you have questions.

Updated 5/02/22

Reactions after booster doses are like those after primary doses. Most side effects are mild to moderate and last 2 days or less. As with the primary series, serious side effects are rare. For more details, visit the CDC webpage Safety of COVID-19 Vaccines. The benefits of getting a booster dose outweigh any known and potential risks.

Updated 5/02/22

No, you do not need a doctor’s note or prescription to get a booster dose. You can self-attest (self-report) if you are eligible. When you go to the location, take proof of vaccination such as your CDC white card or digital vaccination record. Visit the How to Get Vaccinated webpage for more information.

Updated 5/02/22


People with moderately or severely weakened immune systems (e.g., blood-related cancers or certain treatments for cancer, organ transplants, and certain autoimmune conditions) are especially vulnerable to COVID-19. They are more likely to get COVID-19 than people with normal immune systems. And if they get infected, they are more likely to get very ill and spread the virus to others.

In addition, some people with weak immune systems don’t build enough protection from the standard COVID-19 primary series. Because of this, it is recommended that they get more doses of vaccine plus getting some of those doses at shorter time intervals.

Posted 5/02/22

If you are age 5 or older and you have a moderately or severely weakened immune system, you should get an additional COVID-19 vaccine dose to complete your primary series. This means a total of:

  • 3 doses of the Pfizer or Moderna vaccine - OR –
  • 1 dose of the J&J vaccine and then one dose of either the Pfizer or Moderna vaccine.

If you are age 12 or older and you have a moderately or severely weakened immune system, you should also get at least one booster dose.

  • If you got Pfizer or Moderna vaccines for your primary series, you should get a booster dose at least 3 months after your 3rd dose for a total of 4 doses.
  • If you got a J&J vaccine as your primary dose and a Pfizer or Moderna vaccine as your additional dose, you should get a booster at least 2 months after the Pfizer or Moderna dose for a total of three doses.

If you are age 12 or older, you have the option to get a 2nd booster of a Pfizer or Moderna vaccine at least 4 months after your first booster for a total of 5 doses. Consider getting this booster as soon as possible.

Ask your doctor about the best timing of your additional and/or booster dose(s) based on your current treatment plan. This is especially important if you are about to start or restart immunosuppressive treatment.

See the COVID-19 Vaccine Schedule at for information on all recommended primary and booster doses for people who are immunocompromised (2nd page).

Posted 5/02/22

It is important to take other steps to protect yourself from COVID-19 in addition to getting the COVID-19 vaccine:

  • Talk to your doctor about medicine to prevent COVID-19. A medicine called Evusheld is now available to prevent COVID-19 infection in people who can’t build enough protection from the vaccine alone. It is given as 2 separate injections into the buttocks during a single visit. It can be given to people age 12 and over who weigh at least 88 pounds. For more information, see the webpage
  • Wear a protective mask such as a well-fitting respirator (e.g., N95, KN95, KF94) or a double mask for a higher level of protection. Avoid crowded indoor places or spaces with poor air flow when possible. For details, see and
  • Encourage the people that you spend time with to help protect you. They should stay up to date with their COVID-19 vaccines, get a 2nd booster if eligible, and take other steps to reduce their risk of getting and passing COVID-19 to you.
Posted 5/02/22

Getting the vaccine

Vaccines are available at hundreds of locations throughout LA County such as clinics, pharmacies, worksites, schools, places of worship, and other community locations. In-home vaccination is available for people who are homebound. Many locations do not require an appointment.

To get a vaccine visit and select “Click Here to Get Vaccinated“ to find a location or request an in-home vaccination. If you need help, you can call the DPH Vaccine Call Center at 833-540-0473, 7 days a week from 8am to 8:30pm. They can arrange in-home vaccination, free transportation to a vaccination site, or help with paratransit and other services for people with disabilities. Information is also available in multiple languages 24/7 by calling 2-1-1.

Updated 5/05/22

No. If you have insurance, your doctor or pharmacy may charge your insurance company a fee for giving the vaccine. People without health insurance can also get COVID-19 vaccines at no cost. There are no out-of-pocket payments for anyone.

Reviewed 5/05/22

No. COVID-19 vaccine is being given at no cost regardless of immigration status. You will not be asked about your immigration status when you get a COVID vaccine. Your medical information is private and getting a COVID-19 vaccine does not affect your immigration status. You do not need a government-issued ID or a letter from your employer to get a vaccine. For questions about immigration, visit the Office of Immigrant Affairs webpage or call 800-593-8222.

Reviewed 5/05/22

No. When you get a vaccine, you will be asked to give an email address or mobile phone number. This information will be entered into the State of California immunization registry (CAIR) so that you can get a digital COVID-19 vaccine record. It may also be used to send reminders if more COVID-19 vaccine doses are due or recommended. The digital vaccine record is a free and convenient way to prove your vaccination status. It is especially useful if you lose your white vaccine card. You don’t need to provide your email address or cell number to get a vaccine and a white CDC COVID-19 vaccination card. But this may make it harder to get a digital vaccine record later. You can learn more about the digital vaccination record at and about the confidentiality protections here.

Reviewed 5/05/22

The CDC COVID-19 Vaccination Record Card (white card) is the official proof of vaccination. Everyone should be given one when they are vaccinated. Please keep it safe as it cannot be replaced. Consider taking a photo or making a photocopy of it.

Everyone who is vaccinated in California can request a digital COVID-19 Vaccination Record at This is also an official record. It can be downloaded to the Google Pay digital wallet on an Android phone or the Apple Health app on an iPhone. You can also take a screenshot of your Digital COVID-19 Vaccine Record and save it to your camera roll. You can get a record for each person in your family even if you used the same email address or mobile phone number when they got vaccinated. For more information, visit the Vaccination Records webpage.

*If you were vaccinated by a federal agency (e.g., Department of Defense, Indian Health Service or Veterans Affairs), you must request a vaccine record from the agency directly.

Reviewed 5/05/22

Youth under 18 need consent from a parent/guardian or caregiver to get vaccinated. If you cannot be present, you may be allowed to give consent by phone, video, or in writing. Check the consent requirements of the place where you plan to go. If it is a location run by Public Health, you can see the requirements and download a consent form at - click on ‘preparing for your visit’ or call the Vaccine Call Center at 1-833-540-0473 (8am-8:30pm daily).

Some exceptions apply. Minors ages 15 years or older who are self-sufficient (e.g., emancipated or self-sufficient minor, married, or previously married) can give their own consent. If you are a foster caregiver, relative caregiver, or Short-Term Residential Therapeutic Program (STRTP) staff you can provide consent as long as the foster child agrees. If you are a foster caregiver and you do not give consent but your foster child wants to get a vaccine, they can contact their legal counsel.

New 5/05/22

Photo ID may be required at some vaccination locations. If you are a guardian of a child in foster care and your foster child does not have a photo ID, have them contact their legal counsel. Another option is to go to a location run by the Los Angeles County Department of Public Health, which does not require a photo ID.

See above for information about consent. Check the requirements of the place you plan to go to. They may be found on their webpage or in an appointment confirmation email or text. For information about the requirements at LA County Department of Public Health vaccine sites, visit - click on ‘preparing for your visit’ or call the Vaccine Call Center at 1-833-540-0473 (8am-8:30pm daily).

New 5/05/22

Yes. 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.

Getting COVID-19 offers some protection from future illness with COVID-19, sometimes called “natural immunity.” The level of protection people get from having COVID-19 may vary depending on how mild or severe their illness was, the time since their infection, and their age. There is currently no test available that can reliably determine if a person is protected from infection.

It is safe to get the vaccine after getting COVID-19, but you should wait until after you have recovered from being sick (if you had symptoms) and your isolation period is over. This is so that you don’t infect healthcare workers and others when you go to get vaccinated.

If you are due for a booster dose and were recently infected, you may choose to delay your booster dose for 3 months after the infection. This is because recent studies have shown that increasing the time between your infection and vaccination may improve your immune response. Also because there is a lower risk of re-infection for the weeks to months after your infection.

If you were sick with multisystem inflammatory syndrome of children or adults (MIS-C or MIS-A), talk with your doctor before getting a COVID-19 vaccine.

Updated 5/05/22

Yes. Adults and children age 5 and over can get a COVID-19 vaccine at the same time as other vaccines, such as measles, whooping cough, and flu. If your child gets a COVID-19 vaccine at a place that doesn’t offer the other vaccines that they need, you can go to a different location to get them at any time. There is no need to wait between vaccines.

Reviewed 5/05/22

Most routine medical procedures or screenings can be done before or after getting a COVID-19 vaccine.

Note: if you are due for a routine screening mammogram and have been recently vaccinated for COVID-19, ask your doctor how long you should wait before you get your mammogram. People who have received a COVID-19 vaccine may get swelling in the lymph nodes (called lymphadenopathy) in the underarm near where they got the shot. This swelling is a normal sign that the body is building protection against COVID-19. This temporary swelling could cause a false reading on a mammogram, so it is important to tell the staff about your vaccination. For more details, see the Society of Breast Imaging’s Recommendations for Women Receiving the COVID-19 Vaccine.

The COVID-19 vaccine can also affect the results of some kinds of screening tests for tuberculosis (TB), see the CDC webpage COVID-19 Vaccination and Other Medical Procedures.

Reviewed 5/05/22
  • Remember to bring the required documentation and your email address or mobile phone number if you have one. If you made an appointment, read the information in the confirmation email. If you have any questions, it may be helpful to write them down.
  • You should receive a paper or electronic version of a fact sheet that tells you more about the specific COVID-19 vaccine you are getting. Each approved and authorized COVID-19 vaccine has its own fact sheet that contains information to help you understand the risks and benefits of receiving that specific vaccine. Learn more about different COVID-19 vaccines.
  • Plan to stay at the appointment for up to an hour. This includes 15-30 minutes for you to be observed after you receive your vaccination.
  • Do not stop your routine medicines before getting vaccinated unless your doctor recommends it.
  • It is not recommended you take over-the-counter medicine (such as ibuprofen, aspirin, or acetaminophen) before vaccination to try to prevent vaccine-related side effects. It is not known how these medications might affect how well the vaccine works. If you take these medications regularly for other reasons, you should keep taking them before you get vaccinated. It is also not recommended to take antihistamines before getting a COVID-19 vaccine to try to prevent allergic reactions.
  • Wear a mask and clothing that will allow easy access to your upper arm where the vaccine will be given. Eat a light snack before your appointment and stay hydrated (bring extra water, just in case).
  • If you need to get another dose of COVID-19 vaccine, make sure that you know how and when to get it before you leave the vaccination site.
NEW 5/05/22

About the Vaccine

Vaccines work by preparing your body’s natural defenses to recognize and fight off germs that can make you sick.

  • Some vaccines have dead or weakened versions of the germ.
  • Others have substances made to look like part of the germ.
  • The currently available COVID-19 vaccines teach the body to make proteins that look like part of the virus that causes COVID-19. They do not have any form of the COVID-19 virus, live, weakened, or dead. (See the question “How do the COVID-19 vaccines work?” below for more information).

When you get any vaccine, your immune system responds by:

  • Making antibodies. These are proteins produced naturally by the immune system to fight disease.
  • Preparing your immune cells to respond to future infection.
  • Remembering the disease and how to fight it. If you are exposed to the germ after getting the vaccine, your immune system can quickly destroy it before you become sick.

This is what makes vaccines so effective. Instead of treating a disease after it happens, vaccines can prevent us from getting sick in the first place.

Updated 5/03/22

All 3 COVID-19 vaccines work by teaching our immune cells how to make copycat spike proteins (the crown-like spikes on the surface of the COVID-19 virus). Making the spike protein does not harm our cells.

  • Our immune system sees the spike protein and knows that it doesn’t belong there.
  • Our bodies react by building an immune response. It makes antibodies that can act against the COVID-19 virus’s spike protein and it prepares immune cells. This will protect us if we are exposed to the virus in the future.

The COVID-19 vaccines differ in how they teach our cells to make the spike protein

  • The vaccines made by Pfizer and Moderna are called mRNA vaccines. Messenger RNA (mRNA) is genetic material that tells our bodies how to make proteins. The mRNA in the vaccine is wrapped in oily bubbles (known as lipid nanoparticles). When the mRNA enters our cells, it teaches them how to make copies of the spike protein. The mRNA does not enter the cell nucleus and does not interact with DNA in any way.
  • The vaccine made by J&J/Janssen is called a viral vector vaccine. The vector (or vehicle) uses a harmless virus to carry the genetic material to our cells. Our cells read the genetic material and make mRNA, and this mRNA teaches our cells to make the spike protein. The viral vector is a harmless version of a common cold virus. It can’t replicate inside our cells or cause illness and it cannot change our DNA in any way.
Updated 5/02/22

No, none of COVID-19 vaccines available for use in the United States contain any fetal tissue or fetal cells.

  • Pfizer and Moderna did not use any fetal cell lines to develop or produce their COVID-19 vaccines. But they did use a fetal cell line for laboratory testing before their vaccines were tested on people.
  • Johnson & Johnson used a fetal cell line to develop and test their COVID-19 vaccine. They also use it for production. The COVID-19 vaccines themselves do not contain any fetal cells.

The fetal cell lines were made in laboratories from cells from 2 abortions conducted in 1973 and 1985. None of the fetal cells used came from a recent abortion or from an abortion done for the sole purpose of vaccine development or other research.

The Catholic Church has reviewed the use of fetal cells for this purpose and has stated that “it is morally acceptable to receive COVID-19 vaccines that have used cell lines from aborted fetuses in their research and production process.” If this issue is of concern to you, we encourage you to review the document COVID-19 Vaccine and Fetal Cell Lines carefully so you can make an informed decision about getting vaccinated.

Reviewed 5/09/22
Posted 5/03/22

Safety and side effects

Common side effects after a COVID-19 vaccine include:

  • Pain, redness, or swelling in the arm where the vaccine was given
  • Fever, chills, and muscle aches
  • Headache
  • Feeling tired

Side effects are normal and a sign that the vaccine is working. It shows that your body is learning to fight the virus and is building immunity. It is important to get all the recommended doses even if you got side effects after an earlier dose unless a vaccination provider or your doctor tells you not to.

See CDC Possible Side Effects After Getting a COVID-19 Vaccine.

Updated 5/09/22

Reactions after getting a COVID-19 vaccine can vary from person to person. Most people in clinical trials of the COVID-19 vaccines had only mild side effects, and some of them had no side effects at all. Those people still had a strong immune response to the vaccine. Vaccination protects you from severe COVID-19 infection whether or not you have side effects after vaccination.

New 5/09/22

Yes, serious side effects can happen but are very rare. Vaccine safety monitoring systems have identified the four serious health problems, described below. The Pfizer and Moderna COVID-19 vaccines are now recommended over the J&J vaccine. One reason for this is because of the rare, but serious side effects linked with J&J vaccine. If you receive a vaccine, see Vaccine Side Effects to learn about possible symptoms to look out for.

  • Anaphylaxis: Anaphylaxis is a rare but serious allergic reaction that can happen after taking a medication or getting any vaccine. Everyone is observed for a short time after getting a COVID-19 vaccine so that if anaphylaxis does happen, it can be treated right away. Other less severe allergic reactions can also happen. Learn more on the CDC webpage Allergic Reactions after COVID-19 Vaccination.
  • Thrombosis with thrombocytopenia syndrome (TTS) after J&J vaccine: TTS is a rare but serious, and sometimes fatal condition involving blood clots and low platelets. TTS has been reported across a wide age range in males and females who received the J&J vaccine. Women ages 18-49 years should especially be aware of the rare but increased risk of this adverse event. To learn more, visit the CDC’s Adverse Events Reported After COVID-19 Vaccination.
  • Guillain-Barré Syndrome (GBS) after J&J vaccine: GBS is a rare disorder where the body’s immune system damages nerve cells. This causes muscle weakness and sometimes paralysis. Most people fully recover from GBS, but some have permanent nerve damage. GBS has been reported in people who received the J&J vaccine. There were more cases in men, especially men age 50 and older. Nearly all of the people became ill within 6 weeks of getting the vaccine. Most became ill in the first 3 weeks. To learn more, visit the CDC’s Adverse Events Reported After COVID-19 Vaccination.
  • Myocarditis and pericarditis after Pfizer or Moderna vaccines: Myocarditis is inflammation of the heart muscle and pericarditis is inflammation of the outer lining of the heart. Myocarditis and pericarditis after COVID-19 vaccination are rare. Most people with myocarditis or pericarditis after vaccination improve with medicine and rest and feel better quickly. People who experience these conditions can usually return to their normal daily activities after their symptoms improve.

    Most of the cases have been reported after the second dose of Pfizer or Moderna vaccine. Male adolescents and young adults are more likely to be affected. Extending the time between 1st and 2nd doses has been shown to decrease the risk of myocarditis. This is one of the reasons why it is now recommended that teens and young adults consider getting the second dose 8 weeks after their first dose. The risk of myocarditis appears to be lower after a booster dose than after the second dose of vaccine.

    Children ages 5-11 receive one-third the dose of Pfizer vaccine compared to people ages 12 and over. In a study published by the CDC, after approximately 8 million doses of pediatric Pfizer vaccine were given to children 5-11 years of age, 11 cases of myocarditis were reported and verified. Most of these cases were mild and recovered quickly.

    A recent study of people aged 5 and over found that the risk of heart complications, such as myocarditis, pericarditis, and multi-system inflammatory disease (MIS-C) was higher after having COVID-19 infection than after getting one or more doses of Pfizer or Moderna vaccines. This finding was seen in males and females of all ages. It is also important to note that vaccine-associated myocarditis is milder and does not last as long as myocarditis due to other causes.

For more information, visit the CDC’s Selected Adverse Events Reported After COVID-19 Vaccination.

To date, over 575 million doses of COVID-19 vaccine have been given in the US. Although side effects may happen, they are very rare. The benefits of staying up to date with COVID-19 vaccines outweigh the risks.

Updated 5/09/22

No. Long-term side effects are very unlikely. Based on what we know from other vaccines, long-term side effects happen within six weeks of getting vaccinated. For this reason, the Food and Drug Administration (FDA) required companies making COVID-19 vaccines to follow trial participants for at least eight weeks. And the participants in the vaccine trials continue to be followed even though the vaccines have been authorized/approved for use. In addition, the CDC continues to closely monitor COVID-19 vaccines after they are authorized/approved and licensed. It has been well over a year since COVID-19 vaccines have been widely available (and even longer since the start of the vaccine trials). Millions of people have received COVID-19 vaccines and no long-term side effects have been identified.

In contrast, we do know that the virus that causes COVID-19 can cause several long-term effects in both adults and in children. For example, some people continue to have symptoms such as feeling very tired, having difficulty sleeping, headaches, and shortness of breath for months after their initial COVID-19 infection, often referred to as long COVID. Further, a severe condition called Multi-System Inflammatory Syndrome can affect children (MIS-C) and adults (MIS-A). MIS is a rare but serious condition associated with COVID-19 in which different body parts become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs. Many patients need to be hospitalized and, tragically, some die. COVID-19 vaccination offers protection against these “long-term” effects of the virus.

Updated 5/09/22

If you have an adverse event (possible side effect) after you are vaccinated, even if you aren't sure that the vaccine caused it, please report it to VAERS. The Vaccine Adverse Event Reporting System is an early warning system that the FDA and CDC use to detect possible safety problems. To make a report, call 1-800-822-7967 or visit

If you have signed up for V-Safe, CDC’s after-vaccination health checker, you can also report your symptoms through the smartphone app.

Neither VAERS nor V-safe provide medical advice. If you have symptoms or health problems that concern you at any time following COVID-19 vaccination, please contact your healthcare provider or seek medical treatment.

Reviewed 5/09/22

Nearly all the ingredients in COVID-19 vaccines are also ingredients in many foods – fats, sugars, and salts. Pfizer and Moderna COVID-19 vaccines also contain messenger RNA (mRNA). The Johnson & Johnson/Janssen COVID-19 vaccine contains a harmless version of a virus unrelated to the virus that causes COVID-19. These give instructions to cells in your body to create an immune response. This response helps protect you from getting sick with COVID-19 in the future. After the body produces an immune response, it discards all the vaccine ingredients just as it would discard any information that cells no longer need. This process is a part of normal body functioning.

COVID-19 vaccines do NOT contain ingredients like preservatives (like thimerosal or mercury), tissues (like aborted fetal cells or any materials from an animal), antibiotics, food proteins (like egg or nut products), medicines, latex, or metals. Learn more about what ingredients are and are not in Pfizer, Moderna, and Johnson & Johnson COVID-19 vaccines.

Updated 5/09/22

No. You cannot get COVID-19 from the vaccine. None of the COVID-19 vaccines has the virus that causes COVID-19 in them. Sometimes people get a fever or feel tired for a day or two after getting a vaccine. These vaccine side effects are normal and are a sign that the body is building immunity. They should go away in a few days.

Updated 5/09/22

No. Vaccines won’t cause you to test positive on a PCR or antigen viral test (swab or spit tests, including self-tests) that looks for current COVID-19 infection. You may test positive on some antibody (blood) tests. This is because the vaccines work by teaching your body to make antibodies.

See the public health testing webpage to learn more about COVID-19 tests.

Updated 5/09/22

It depends.

  • People who are allergic to things like oral medication, food (including eggs), latex, pets, or pollen, or people who have a family history of allergies, can be vaccinated.
  • If you have had an allergic reaction to a vaccine or injectable therapy, even if it was not severe, talk to your doctor to decide if it is safe to get vaccinated.
  • If you are allergic to Polyethylene Glycol (PEG), you should not get the Pfizer or Moderna vaccine. Ask your doctor if you can get the J&J vaccine.
  • If you are allergic to polysorbate, you should not get the J&J vaccine. Ask your doctor if you can get the Pfizer or Moderna vaccine.

There is a small risk of anaphylaxis (a severe type of allergic reaction) with any vaccine. This is why everyone is observed for a short time after getting a COVID-19 vaccine.

Information about allergic reactions may change. Be sure to check the latest guidance on the CDC COVID-19 Vaccines for People with Allergies webpage and talk to your doctor.

Reviewed 5/09/22


Yes! The CDC and pregnancy experts, including the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine, and the American College of Nurse-Midwives, recommend that pregnant people get vaccinated against COVID-19. For the best protection, this includes getting a booster dose as well as the primary vaccine series. The vaccine can be given at any stage of pregnancy.

Updated 5/02/22

COVID-19 is a serious concern during pregnancy. Pregnant and recently pregnant people who get COVID-19 are more likely to become severely ill, be hospitalized, and die compared to people who are not pregnant. In addition, people who get COVID-19 during pregnancy are more likely to get complications that can affect their pregnancy and developing baby. These include preterm birth and stillbirth.

COVID-19 vaccination protects both pregnant people and their newborns from severe illness from COVID-19. In studies of people who have received the Pfizer and Moderna vaccines, protective antibodies against the virus were found in the umbilical cord blood and in breastmilk. In addition, a recent study confirmed that vaccination during pregnancy was effective in protecting infants under the age of 6 months from being hospitalized due to COVID-19.

Posted 5/02/22

There is no evidence that COVID-19 vaccination causes any problems with pregnancy, including the development of the placenta. The CDC continues to monitor people who have been vaccinated during all trimesters of pregnancy to better understand the effects on pregnancy and babies. Over a hundred thousand pregnant people who have been vaccinated have been monitored and no increased risk of pregnancy loss, growth problems, or birth defects has been found. COVID-19 vaccines do not cause COVID-19 infection, including in people who are pregnant or their babies. None of the COVID-19 vaccines contain live virus. They cannot make anyone sick with COVID-19, including people who are pregnant or their babies.

Evidence continues to build, showing that COVID-19 vaccination before and during pregnancy is safe and effective. It suggests that the benefits of receiving a COVID-19 vaccine outweigh any known or potential risks of vaccination during pregnancy.

For more information, visit and the CDC webpage COVID-19 Vaccines While Pregnant or Breastfeeding.

If you are pregnant and have questions about getting vaccinated, talk to your doctor. You can also talk to experts at MotherToBaby who are available to answer questions in English or Spanish. This free and confidential service is available Monday–Friday 8am–5pm. You can call 866-626-6847, text 855.999.8525, e-mail or start a chat at

Posted 5/02/22

Yes! Experts, including the CDC, the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine, and the American College of Nurse-Midwives recommend that people who are breastfeeding be vaccinated against COVID-19.

Lactating people were not included in the vaccine studies. However, based on what we know about how these vaccines work, the vaccines are not thought to be a risk for the baby. Recent studies have shown that breastfeeding people who have received the Pfizer or Moderna vaccines have antibodies in their breastmilk, which might help to protect their babies. These vaccines do not pass into breastmilk.

Updated 5/02/22

Yes. The CDC and medical experts recommend vaccination for everyone aged 5 years and older. This includes people who are pregnant, trying to get pregnant, or who may want to get pregnant in the future as well as their partners.

There is no evidence that any vaccine, including COVID-19 vaccines, cause fertility problems in females or males. There is also no evidence that COVID-19 vaccines affect puberty or teenage development.

A small study of 45 healthy men who received an mRNA COVID-19 vaccine reviewed sperm characteristics before and after vaccination. Researchers looked at sperm quantity and movement and found no significant changes in these after vaccination. By comparison, a different study found a decrease in fertility for up to 60 days in men who were infected with COVID-19. This study of over 2,000 people also found no differences in pregnancy success rates in men and women who were vaccinated compared with those who weren’t. Many people have become pregnant after receiving a COVID-19 vaccine. For more information see the CDC webpage COVID-19 Vaccines for People Who Would Like to Have a Baby.

Updated 5/02/22

Some women have reported a change in their period after getting the COVID-19 vaccine such as late periods, heavier flow, and painful cramps. There is limited research on COVID-19 vaccination and the menstrual cycle. Two recent studies showed common, but minor, changes after COVID-19 vaccination. These included changes in the length of the menstrual cycle and the time between cycles as well as heavier bleeding than usual. These changes were temporary.

It is important to remember, many things can cause a change to menstrual cycles such as stress, and changes in sleep, diet, exercise, and some medicines. It is also important to note that irregular periods are very common among teens and may have no specific cause at all. If you have concerns about your period or your child’s periods, talk to a doctor.

Updated 5/02/22
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