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COVID-19 (coronavirus 2019) vaccine, Janssen - Johnson & Johnson

Generic Name: COVID-19 (coronavirus 2019) vaccine, Janssen - Johnson & Johnson (KOE vid (koe ROE na vye rus) VAX een)
Brand Name: Janssen COVID-19 Vaccine PF
Dosage Forms: intramuscular suspension (-)

Medically reviewed by on March 11, 2021. Written by Cerner Multum.

What is the COVID-19 vaccine?

COVID-19 is a serious disease caused by a coronavirus called SARS-CoV-2 (Serious Acute Respiratory Syndrome Coronavirus 2). COVID-19 is spread from person to person through the air.

COVID-19 can affect your lungs or other organs. Symptoms may be mild or serious and include fever, chills, cough, sore throat, shortness of breath, tiredness, body aches, headache, loss of taste or smell, runny or stuffy nose, nausea, vomiting, or diarrhea.

The US Food and Drug Administration (FDA) has authorized emergency use of COVID-19 vaccine to help prevent infection with SARS-CoV-2. The Janssen vaccine is for use only in adults.

This vaccine may help your body develop immunity to SARS-CoV-2. However, this vaccine has not been approved to prevent or treat coronavirus or COVID-19.

COVID-19 vaccine is experimental and all of its risks are not yet known. The COVID-19 vaccine does not contain coronavirus and cannot give you COVID-19.

Like any vaccine, COVID-19 vaccine may not provide protection in every person.


The FDA has authorized emergency use of this vaccine as it may help prevent infection with COVID-19. This vaccine has not been approved to prevent or treat coronavirus or COVID-19.

Becoming infected with COVID-19 is much more dangerous to your health than receiving this vaccine.

Before taking this medicine

Tell your vaccination provider if you've ever had an allergic reaction to a COVID-19 vaccine, or if you are allergic to polysorbate-80.

If you are infected with COVID-19, are waiting for testing results, or are exposed to someone infected with COVID-19: You may not be able to receive this vaccine until you have no symptoms and/or your required quarantine period has ended. Receiving this vaccine will not make you less contagious to other people if you are infected with COVID-19 but you have no symptoms.

If you had COVID-19 and were treated with monoclonal antibodies or convalescent plasma: You should wait 90 days before getting a COVID-19 vaccine. Ask your doctor if you are unsure about any COVID-19 treatments you received.

Tell the person giving you this vaccine if you have a fever, or if:

  • you've received any treatment or medication for COVID-19 infection in the past 90 days;

  • you've received or will receive any other vaccine within 14 days before or after your COVID-19 vaccine;

  • you have any allergies;

  • you have a weak immune system caused by disease or by using certain medicine (this vaccine may not be as effective if you are immunosuppressed);

  • you have bleeding problems;

  • you use a blood thinner (such as warfarin, Coumadin, or Jantoven); or

  • you are pregnant or breastfeeding.

COVID-19 is more likely to cause serious illness or death in a pregnant woman. Not all risks are known yet, but this vaccine is likely to be less harmful than becoming infected with COVID-19 during pregnancy.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of this vaccine on the baby.

How is this vaccine given?

Read all vaccine information sheets provided to you.

COVID-19 vaccine is given as an injection (shot) into a muscle. The Janssen vaccine is given as a single dose. You should not receive this vaccine as a second shot for another type of COVID-19 vaccine (such as the Moderna or Pfizer types).

You will receive a vaccination card showing the date and type of COVID-19 vaccine you received.

You will be "fully vaccinated" if it has been at least 2 weeks since you received this vaccine. You may become infected with COVID-19 if the vaccine has not had enough time to provide protection.

Even after you are fully vaccinated, keep using infection control methods when you are in public or around others who may not have been vaccinated. This includes social distancing, hand-washing, using protective face covering, disinfecting surfaces you touch a lot, and not sharing personal items with others.

Receiving a COVID-19 vaccine will not cause you to test positive on a coronavirus test. However, once your body develops immunity to COVID-19, you could test positive on an antibody test (a test to detect immunity in your body from previous exposure to coronavirus).

It is not known how long this vaccine will protect you from infection with COVID-19. It also is not known how long immunity will last in a person who's been infected with and recovered from COVID-19. COVID-19 vaccine is still being studied and all of its risks are not yet known. Updated federal public health recommendations may be found at

What happens if I miss a dose?

The Janssen COVID-19 vaccine is used as a single dose and does not have a booster schedule.

What happens if I overdose?

An overdose of this vaccine is unlikely to occur.

What should I avoid after receiving this vaccine?

Avoid receiving other vaccines without first seeking medical advice.

This vaccine side effects

Get emergency medical help if you have signs of an allergic reaction: hives, itching; confusion, dizziness, fainting; vomiting, diarrhea; fast heartbeats, wheezing, difficult breathing; swelling of your face, lips, tongue, or throat.

An allergic reaction is more likely to occur within a few minutes to 1 hour after you receive the vaccine. You will be treated quickly if you have a reaction.

Becoming infected with COVID-19 is much more dangerous to your health than receiving this vaccine. Serious side effects other than an allergic reaction may include:

  • pale or clammy skin, sweating, feeling warm or cold;

  • feeling anxious, nauseated, weak, or light-headed;

  • slow heartbeats, rapid breathing; or

  • changes in vision or hearing.

Fever may be a normal symptom as your body begins to develop immunity to COVID-19. However, you should call your doctor right away if you have any side effects that concern you.

Common side effects may include:

  • fever;

  • pain, redness, or swelling where the shot was given;

  • nausea;

  • headache, muscle pain; or

  • feeling tired.

You may be able to treat these effects with an over-the-counter pain reliever such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil, and others). Follow the label directions or your vaccination provider's instructions.

Other side effects, mild or serious, may occur with more widespread use of COVID-19 vaccine.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report vaccine side effects to the US Department of Health and Human Services at 1-800-822-7967.

You may also use a smartphone-based program called V-safe to communicate with the Centers for Disease Control and Prevention (CDC) about any health problems you have after receiving a COVID-19 vaccine:

What other drugs will affect this vaccine?

Before receiving this vaccine, tell your vaccination provider about all other vaccines you have received in the past 14 days. Also tell the provider about all your current medicines. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

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Further information

  • Your vaccination provider, pharmacist, or doctor can provide more information about this vaccine. Additional information is available from your local health department or the Centers for Disease Control and Prevention.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.