Janssen COVID-19 Vaccine (Johnson & Johnson) Questions

Below are answers to commonly asked clinical questions about Janssen COVID-19 Vaccine. Get answers to other frequently asked questions:

Vaccination Schedule and Use

Based on an updated risk-benefit analysis, use of mRNA COVID-19 vaccines is preferred over the Janssen COVID-19 Vaccine for all vaccine-eligible people ages 18 years or older for the primary series and booster dose. Start the two-dose mRNA COVID-19 vaccine series, even if there is uncertainty about how the patient will receive their second dose.

In some cases, you may administer Janssen COVID-19 to patients ages 18 years  and older:

  • When there is a contraindication to mRNA COVID-19 vaccines (e.g., severe allergic reaction after a previous dose or to a component of an mRNA COVID-19 vaccine)
  • When a person would otherwise remain unvaccinated for COVID-19 due to limited access to mRNA COVID-19 vaccines.
  • When a person wants to receive the Janssen COVID-19 Vaccine despite the safety concerns identified

In these situations, inform patients about the:

  • Risk and symptoms of Thrombosis with Thrombocytopenia Syndrome (TTS) that could occur after vaccination (typically within 2 weeks)
  • Need to seek immediate medical care should such symptoms develop
  • Availability of mRNA COVID-19 vaccines instead of the Janssen COVID-19 Vaccine

Learn more about considerations for Janssen COVID-19 Vaccine, including the symptoms of TTS.

All doses of the primary series should be completed with the same product. In limited, exceptional situations where a patient received the first dose of an mRNA COVID-19 vaccine but is unable to complete the series with either the same or different mRNA COVID-19 vaccine (e.g., due to contraindication), you may consider administering a single dose of Janssen COVID-19 Vaccine, with a minimum interval of 28 days between doses.

Inform people for whom the Janssen COVID-19 Vaccine is being considered of the risk and symptoms of TTS. Vaccination with the Janssen COVID-19 Vaccine should include consideration of the benefits and harms. For more information, see

Preferential Recommendation for mRNA COVID-19 vaccines

No, people who received Janssen COVID-19 Vaccine for the primary series or booster dose do not need to be revaccinated for either dose. The Advisory Committee on Immunization Practices’ preferential recommendation does not impact doses people have already received.

Learn more about considerations for Janssen COVID-19 Vaccine.

No, people who have already received Janssen COVID-19 Vaccine should not get more than 1 booster dose at this time. Those that have received

  • A single primary dose of Janssen COVID-19 Vaccine should receive a single booster dose at least 2 months after the primary dose. An mRNA COVID-19 vaccine is preferred over the Janssen COVID-19 Vaccine for booster vaccination.
  • A single primary dose of Janssen COVID-19 Vaccine followed at least 2 months later by any FDA-authorized or FDA-approved COVID-19 vaccine booster, do not need any more COVID-19 vaccine doses at this time.

CDC will continue to monitor COVID-19 vaccine safety and effectiveness data to determine if recommendations should change in the future.

Learn more about considerations for Janssen COVID-19 Vaccine.

In most situations, Pfizer-BioNTech or Moderna COVID-19 vaccines are preferred over the Janssen COVID-19 Vaccine for primary and booster vaccination. However, you may offer the Janssen COVID-19 Vaccine in some situations as described below:

  • When there is a contraindication to mRNA COVID-19 vaccines (e.g., severe allergic reaction after a previous dose or to a component of an mRNA COVID-19 vaccine)
  • When a person would otherwise remain unvaccinated for COVID-19 due to limited access to mRNA COVID-19 vaccines
  • When a person wants to receive the Janssen COVID-19 Vaccine despite the safety concerns identified

Inform anyone who elects to receive a Janssen COVID-19 Vaccine booster about

  • The risk and symptoms of TTS that could occur after vaccination (typically within 2 weeks after receipt)
  • The need to seek immediate medical care should such symptoms develop at any time
  • The availability of mRNA COVID-19 vaccines instead of the Janssen COVID-19 Vaccine.

This guidance applies to the primary (first) and booster (second) doses of Janssen COVID-19 Vaccine. People should seek medical attention immediately if they develop any of the following symptoms:

  • Shortness of breath
  • Chest pain
  • Leg swelling
  • Persistent abdominal pain
  • Severe or persistent headaches or blurred vision
  • Easy bruising or tiny blood spots under the skin beyond the site of the injection.

Learn more about considerations for Janssen COVID-19 Vaccine.

People with a contraindication to one of the mRNA vaccines may be able to receive Janssen COVID-19 Vaccine. Vaccination with Janssen COVID-19 Vaccine is considered a precaution in this situation. The following considerations can be used to help you conduct a risk assessment for vaccination in individuals with a precaution to vaccination:

  • Risk of exposure to SARS-CoV-2 (e.g., exposure because of occupational or institutional setting)
  • Risk of severe disease or death due to COVID-19 (e.g., because of age, underlying medical conditions)
  • The unknown risk of anaphylaxis (including fatal anaphylaxis) following COVID-19 vaccination in a people with a history of an immediate allergic reaction to other vaccines or injectable therapies. Consultation with an allergist-immunologist may help to clarify the risk assessment for these individuals.
  • Ability of the patient to be vaccinated in a setting where appropriate medical care is immediately available for anaphylaxis.

Learn more about

Booster Doses

All people ages 18 years and older who received a single-dose Janssen primary series should receive a booster dose at least 2 months (8 weeks) after completing their Janssen primary series. An mRNA COVID-19 vaccine is preferred over the Janssen COVID-19 Vaccine for booster vaccination.

Learn more about considerations for COVID-19 vaccine booster doses.

The 2-month interval is measured in weeks (i.e., 8 weeks), consistent with the Advisory Committee on Immunization Practices’ General Best Practice Guidelines for Immunizationpdf icon. For example, if an eligible patient completed a single-dose Janssen primary series on September 1, 2021, they can receive a booster dose as soon as October 27, 2021.

Everyone 18 years of age and older should receive a COVID-19 vaccine booster dose, even if they were younger than 18 years of age at the time of the primary series. Use of an mRNA COVID-19 vaccine for a booster dose is preferred even for those who received Janssen COVID-19 Vaccine for their single dose primary series. However, offering the Janssen COVID-19 Vaccine as a booster is preferable to not providing any COVID-19 vaccine booster in most situations.

Learn more about considerations for selecting which booster dose to receive and considerations for Janssen COVID-19 Vaccine.

A single primary Janssen dose is recommended for people ages 18 years and older who are moderately or severely immunocompromised, followed by a second (additional) dose using an mRNA COVID-19 vaccine at least 28 days (4 weeks) later.

A single booster dose is recommended at least 2 months after the second (additional) dose, for a total of 3 doses (1 Janssen Vaccine dose followed by 1 additional mRNA vaccine dose, then 1 booster dose).

See Appendix B for additional dose information for Janssen COVID-19 Vaccine recipients.

Vaccine Indications, Contraindications, and Precautions

Janssen COVID-19 Vaccine and Risk of Thrombosis with Thrombocytopenia Syndrome (TTS)

TTS is a rare syndrome that involves acute venous or arterial thrombosis and new-onset thrombocytopenia in patients with no recent known exposure to heparin. Although the mechanism that causes TTS is not fully understood, TTS appears to be similar to heparin-induced thrombocytopenia, a rare reaction to heparin treatment.

A more detailed interim case definition of TTSexternal icon is available from the Brighton Collaboration.

The primary symptoms of TTS, which typically occur within 2 weeks following vaccination, include:

  • Shortness of breath
  • Chest pain
  • Leg swelling
  • Persistent abdominal pain
  • Severe or persistent headaches or blurred vision
  • Easy bruising or tiny blood spots under the skin beyond the injection site

See the American Society of Hematology’s guidance for more detailed information on the diagnosis and management of TTSexternal icon.

Cases of TTS following administration of the Janssen COVID-19 Vaccine have been reported in males and females and in a wide age range of individuals 18 years and older. Although the condition is rare, currently available evidence supports a causal relationship between Janssen COVID-19 Vaccine and TTS. Cases of TTS including deaths following administration of the Janssen COVID-19 Vaccine have been reported in males and female, with the highest risk in females ages 30-49 years.

Based on an updated risk-benefit analysis, use of mRNA COVID-19 vaccines is preferred over the Janssen COVID-19 Vaccine for all vaccine-eligible persons.

Weekly updates on TTS are available at Selected Adverse Events Reported after COVID-19 Vaccination.

The clinical presentation of the reported cases among recipients of the Janssen COVID-19 Vaccine (which is based on a human adenoviral vector) is similar to that of recently reported cases from Europe after receipt of the AstraZeneca COVID-19 Vaccine (which is based on a chimpanzee adenoviral vector). The AstraZeneca COVID-19 Vaccine is not currently authorized for use in the United States.

Although the mechanism  of TTS associated with the Janssen COVID-19 Vaccine is unclear, it appears to be similar to another rare immune-mediated syndrome, heparin-induced thrombocytopenia (HIT). People with a history of an episode of an immune-mediated syndrome characterized by thrombosis and thrombocytopenia, such as HIT, should receive a currently FDA-approved or FDA-authorized mRNA COVID-19 vaccine.

Available evidence does not indicate that other thromboembolic conditions (e.g., inherited or acquired thrombophilia, pregnancy, hormonal contraception use) increase the risk of TTS. As with the general population, mRNA COVID-19 vaccines are preferred over the Janssen COVID-19 Vaccine in people with these conditions.

Administration of the Janssen COVID-19 Vaccine is contraindicated in individuals who develop TTS following receipt of a previous Janssen COVID-19 Vaccine (or other COVID-19 vaccines not currently authorized in the United States that are based on adenovirus vectors).

Learn more about considerations for Janssen COVID-19 Vaccine.

People using hormonal birth control can receive any FDA-authorized or approved COVID-19 vaccine. However, as with the general population, mRNA COVID-19 vaccines are preferred over the Janssen COVID-19 Vaccine. There are no recommendations to stop taking hormonal birth control (birth control pills, implant, patch, ring, or shot) before or after receiving the Janssen COVID-19 Vaccine. Although the risk of blood clots is increased with some hormonal birth control methods (e.g., certain types of birth control pills, patch, ring), based on the available data, experts believe that these factors do not make people more likely to develop TTS after receiving the Janssen COVID-19 Vaccine.

COVID-19 vaccination is recommended for people who are pregnant, lactating, trying to get pregnant now, or who might become pregnant soon. mRNA vaccines are recommended for all vaccine-eligible populations, including for people who are pregnant or lactating. Those who are considering receipt of the Janssen COVID-19 Vaccine should be counseled about the rare risk of TTS which can occur (typically within 2 weeks) after receipt of the Janssen COVID-19 Vaccine, and need for a booster dose 2 months or more after the initial dose.

Vaccine Storage and Handling

Yes. After first puncturing the vial, the vial should be held between 2°C and 8°C (36°F and 46°F) for up to 6 hours OR at room temperature (up to 25°C [77°F]) for up to 2 hours.

See Janssen COVID-19 Vaccine Storage and Handling Summarypdf icon for more storage and handling information.

No. After the vial is first punctured, the vaccine vial may be held:

  • For up to 2 hours at room temperature; discard any vaccine not used within 2 hours

—–OR—-

  • For up to 6 hours refrigerated between 2°C and 8°C; discard any vaccine not used within 6 hours

You should not add these time limits together (i.e., you may not hold the vaccine at room temperature for 2 hours and then hold it refrigerated for another 6 hours).

If you do not reach the 2-hour time limit at room temperature, you may transfer the punctured vial to a refrigerated storage unit between 2°C and 8°C for the remaining time, up to 2 hours. For example, a vial held at room temperature for 1 hour after first puncture can be stored in the refrigerator (between 2°C and 8°C) for no more than 1 hour before using or discarding. If the 2-hour time limit at room temperature has been reached, the vaccine must be discarded and cannot be transferred to the refrigerator.

See Janssen COVID-19 Vaccine Storage and Handling Summarypdf icon for more storage and handling information.

The allowed storage time after first vial puncture or dose withdrawal is either a maximum of 6 hours refrigerated or 2 hours at room temperature. These maximum hold times and temperatures are not cumulative. You should discard the punctured vial once it exceeds either of these conditions, even if there are doses remaining. If stored in the refrigerator after the first puncture, the vaccine can be moved to room temperature for brief periods of time for administration. This does not affect the maximum 6-hour hold period for vaccine stored in the refrigerator.

See Janssen COVID-19 Vaccine Storage and Handling Summarypdf icon for more storage and handling information.

For information about transporting vaccine in a syringe go to General FAQs.

For specific information about transporting Janssen vaccine go to “Janssen Transporting Vaccine to Off-Site Clinics”

Vaccine Administration

No. The Janssen COVID-19 Vaccine comes in a multidose vial and does not require reconstitution.

See Janssen COVID-19 Vaccine Preparation and Administration Summarypdf icon for more information.

CDC recommends healthcare providers follow the dosing guidance from the manufacturer as outlined in the Fact Sheet for Healthcare Providers Administering Vaccineexternal icon. CDC will update its guidance if the Emergency Use Authorization (EUA) and ancillary supply kits support obtaining additional doses per vial in the future.

Some interim recommendations for COVID-19 vaccine administration errors differ from ACIP’s General Best Practice Guidelines. Review vaccine administration errors and deviations for COVID-19 vaccines to learn about the interim recommendation for each type of error.

For all vaccine administration errors:

Page last reviewed: March 23, 2022