COVID-19 vaccine, viral vector-Janssen (Investigational)

Brand and Other Names:Ad26.COV2.S (Johnson & Johnson)
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Dosing & Uses


Dosage Forms & Strengths

injection, suspension

  • 5x1010 virus particles/0.5mL (5 doses per vial)

COVID-19 Disease Prevention (EUA)

February 27, 2021: Emergency use authorization (EUA) issued by FDA

EUA updated May 5, 2022 (limited use): Indicated for active immunization to prevent coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals aged ≥18 years for whom other FDA-authorized or approved COVID-19 vaccines are not accessible or clinically appropriate

Also indicated for those who elect to receive the Janssen COVID-19 vaccine because they would otherwise not receive a COVID-19 vaccine

Primary series: 0.5 mL IM as a single dose

Booster dose: Administer either Pfizer or Moderna omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine booster at least 2 months after completion of primary vaccination

CDC COVID-19 vaccine interim immunization schedule

Dosing Considerations

Limitations of effectiveness: May not protect all vaccine recipients

Data unavailable on use of the Janssen COVID-19 vaccine to complete a primary vaccination series initiated with another COVID-19 vaccine

<18 years: Safety and efficacy not established


Adverse Effects

VAERS Reporting

Mandatory for vaccination providers to report to the vaccine adverse events reporting system (VAERS) all vaccine administration errors, serious adverse events, multisystem inflammatory syndrome in adults and children, and hospitalized or fatal cases of COVID-19 following vaccination

May submit report online or fax it to VAERS at 1-877-721-0366


7 days post vaccination; aged 18-59 yr

  • Injection site pain (58.6%)
  • Headache (44.4%)
  • Fatigue (43.8%)
  • Myalgia (39.1%)
  • Use of antipyretic or pain medication (26.4%)
  • Nausea (15.5%)
  • Fever (12.8%)

7 days post vaccination; aged ≥60 yr

  • Injection site pain (33.3%)
  • Headache (30.4%)
  • Fatigue (29.7%)
  • Myalgia (24%)
  • Nausea (12.3%)


7 days post vaccination; aged 18-59 yr

  • Injection site erythema (9%)
  • Injection site swelling (7%)
  • Myalgia, Grade 3 (1.4%)
  • Fatigue, Grade 3 (1.2%)

7 days post vaccination; aged ≥60 yr

  • Use of antipyretic or pain medication (9.8%)
  • Injection site erythema (4.6%)
  • Fever (3.1%)
  • Injection site swelling (2.7%)


7 days post vaccination; aged 18-59 yr

  • Grade 3
    • Headache (0.9%)
    • Injection site pain (0.4%)
    • Injection site erythema (0.3%)
    • Fever (0.3%)
    • Injection site swelling (0.2%)
    • Nausea (0.1%)

7 days post vaccination; aged ≥60 yr

  • Grade 3
    • Fatigue (0.8%)
    • Headache (0.4%)
    • Injection site pain (0.2%)
    • Injection site swelling (0.2%)
    • Myalgia (0.2%)
    • Injection site erythema (0.1%)
    • Fever (0.1%)

Post Authorization Experience

Blood and lymphatic system disorders: Thrombosis with thrombocytopenia, lymphadenopathy, immune thrombocytopenic purpura

Cardiac disorders: Myocarditis, pericarditis

Gastrointestinal disorders: Diarrhea, vomiting

Immune system disorders: Allergic reactions, including anaphylaxis

Nervous system disorders: Guillain-Barré syndrome, syncope, paresthesia, hypoesthesia

Vascular disorders: Capillary leak syndrome, thrombosis with thrombocytopenia, venous thromboembolism (with or without thrombocytopenia)




Known history of severe allergic reaction (eg, anaphylaxis) to any component in vaccine

History of thrombosis with thrombocytopenia following the Janssen COVID-19 Vaccine or any other adenovirus vectored COVID-19 vaccine (eg, AstraZeneca COVID-19 vaccine which is not authorized or approved in the United States)


Vaccine may not protect all vaccine recipients

Immunocompromised persons, including individuals receiving immunosuppressant therapy, may have diminished immune response to the vaccine

Post authorization reports suggest an increased risk of Guillain-Barré syndrome during the 42 days following vaccination

Syncope (fainting) may occur; procedures should be in place to avoid injury from fainting

Post authorization reports suggest an increased risk of immune thrombocytopenia (ITP) during the 42 days following vaccination; individuals with history of ITP should discuss the potential need for platelet monitoring following vaccination with their healthcare clinician

Allergic reactions

  • Appropriate medical treatment used to manage immediate allergic reactions must be immediately available following vaccination
  • Individuals with histories of severe allergic reaction to vaccines should consult their doctors about the COVID-19 vaccine
  • Monitor vaccine recipients for immediate adverse reactions according to the Centers for Disease Control and Prevention guidelines

Thrombosis with thrombocytopenia syndrome (TTS)

  • Extremely rare cases reported of thrombosis involving the cerebral venous sinuses and other sites (including but not limited to the large blood vessels of the abdomen and the veins of the lower extremities) combined with thrombocytopenia
  • Onset of symptoms ~1-2 weeks after vaccination
  • Reporting rate of thrombosis and thrombocytopenia has been highest in females aged 18-49 years; some have been fatal
  • Healthcare professionals should be alert to the signs and symptoms of thrombosis with thrombocytopenia in individuals who received the Ad26.COV2-2 vaccine
  • VAERS reports
    • Through March 18, 2022: Analysis of TTS cases following Janssen COVID-19 vaccine reported to VAERS, 60 confirmed cases have been identified, including 9 fatal cases
    • The reporting rate of TTS is 3.23 per million doses of vaccine administered and the reporting rate of TTS deaths is 0.48 per million doses of vaccine administered
  • TTS definition
    • Thrombosis in an unusual location for a thrombus (ie, cerebral vein, visceral artery or vein, extremity artery, central artery or vein) and new-onset thrombocytopenia (ie, platelet count <150,000/μL) occurring any time after vaccination, OR
    • New-onset thrombocytopenia, thrombosis in an extremity vein or pulmonary artery in absence of thrombosis at an unusual location, and a positive anti-PF4 antibody ELISA test or functional heparin-induced thrombocytopenia (HIT) platelet test occurring any time after vaccination
  • Clinical course
    • The clinical course shares features with autoimmune HIT
    • Use of heparin may be harmful in individuals with suspected thrombosis with thrombocytopenia following vaccination; alternant treatments may be needed
    • Diagnosis must include the following 4 criteria: 1) Ad26.COV2-2 vaccine 4-30 days previously; 2) thrombosis (often cerebral or abdominal); 3) thrombocytopenia; 4) positive PF4 HIT ELISA
    • NOTE: If patient presents with thrombosis and a normal platelet count post-vaccination, they might be in an early stage of VITT; continued assessment for development of thrombocytopenia/VITT required
    • Cases reported in males and females, in wide age range (≥18 yr), with the highest reporting rate (~1 case/100,000 doses administered) in females aged 30-49 yr
    • Overall, ~15% of TTS cases have been fatal
  • Hematology consultation
    • Consultation with hematology specialists is strongly recommended
    • American Society of Hematology has published considerations relevant to the diagnosis and treatment of thrombosis with thrombocytopenia following vaccination
    • Urgent medical evaluation for vaccine-induced immune thrombotic thrombocytopenia (VITT) indicated if any of the following develops: severe headache, visual changes, abdominal pain, nausea/vomiting, backache, shortness of breath, leg pain/swelling, or petechiae/easy bruising

Drug interaction overview

  • Data are not available to assess concomitant administration with other vaccines

Pregnancy & Lactation


Data are insufficient to inform of vaccine-associated risks in pregnancy

Women vaccinated with Janssen COVID-19 vaccine are encouraged to enroll in the pregnancy exposure registry

A smartphone app, v-safe, is also available to report adverse effects to the CDC following vaccination with a COVID-19 vaccine

CDC guidelines for vaccination of pregnant or lactating women


Data are not available to assess effects on breastfed infants or on milk production/excretion

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.



Mechanism of Action

Vaccine is composed of a recombinant, replication-incompetent human adenovirus type 26 vector that after entering human cells, expresses the SARS-CoV-2 spike (S) antigen without virus propagation

An immune response elicited to the S antigen protects against COVID-19



IM Preparation

Suspension is a colorless to slightly yellow, clear to very opalescent suspension

Visually inspect for particulate matter and discoloration; if either of these conditions exists, do not administer

Carefully mix vial contents by swirling gently in an upright position for 10 seconds; do NOT shake

Each dose is 0.5 mL; each vial contains 5 doses; do not pool excess vaccine from multiple vials

IM Administration

For IM injection only


Receiving shipment

  • Once received, do not freeze
  • Initially stored frozen by the manufacturer, then shipped at 2-8ºC (36-46ºF)
  • If vaccine is still frozen upon receipt, thaw in refrigerator at 2-8ºC (36-46ºF)
  • If needed immediately, thaw at room temperature (maximally 25ºC/77ºF)
  • At room temperature, a carton of 10 vials takes ~4 hr to thaw, and an individual vial takes ~1 hour to thaw
  • Do not refreeze once thawed

Unopened vials

  • Refrigerated: 2-8ºC (36-46ºF) and protect form light; do not freeze
  • Room temperature: 9-25ºC (47-77ºF) for up to 12 hr

Opened vials

  • Refrigerated: 2-8ºC (36-46ºF) for up to 6 hr, OR
  • Room temperature: Maximally 25ºC (77ºF) for up to 2 hr
  • Discard if vaccine is not used within these times


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Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.