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Ad26.COV2.S

National Institute of Allergy and Infectious Diseases (NIAID) · Phase 3 active Biologic ✓ Verified Jun 2026

Ad26.COV2.S is a Viral vector vaccine Biologic drug developed by National Institute of Allergy and Infectious Diseases (NIAID). It is currently in Phase 3 development for COVID-19 prevention in adults. Also known as: Janssen COVID-19 Vaccine, JNJ-78436735, JNJ-78436735, VAC31518, Ad26COVS1.

Ad26.COV2.S is a viral vector vaccine that delivers genetic instructions for the SARS-CoV-2 spike protein to stimulate immune responses against COVID-19.

The Janssen COVID-19 vaccine, also known as Ad26.COV2.S, is a vaccine developed by Janssen Vaccines and Johnson & Johnson for COVID-19, SARS, and other related conditions. It is one of the interventions being studied in clinical trials, including a trial examining its immunogenicity in tuberculosis patients.

Likelihood of approval
59.3% vs 58.3% industry baseline
If approved by FDA: likely 2028–2030
Steps remaining: NDA/BLA submission
Confidence: High
Why this estimate
  • Baseline phase 3 → approval rate +58.3pp
    Industry-wide phase 3 drugs reach approval ~58.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
  • Immunology slight uplift +1.0pp
    Mature endpoint landscape (ACR, DAS28, PASI) makes immunology approvals slightly more predictable.
Predicted approval windows by jurisdiction (conditional on FDA approval)
Regulator Country Likely year Lag vs FDA
FDA US 2028–2030
EMA EU 2029–2031 +0.7 yr
MHRA GB 2029–2031 +0.7 yr
Health Canada CA 2029–2032 +0.9 yr
TGA AU 2029–2032 +1.2 yr
PMDA JP 2029–2032 +1.5 yr
NMPA CN 2030–2033 +2.3 yr
MFDS KR 2029–2032 +1.4 yr
CDSCO IN 2029–2033 +1.8 yr
ANVISA BR 2030–2033 +2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic nameAd26.COV2.S
Also known asJanssen COVID-19 Vaccine, JNJ-78436735, JNJ-78436735, VAC31518, Ad26COVS1, JNJ-78436735, Ad26COVS1
SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
Drug classViral vector vaccine
TargetSARS-CoV-2 spike protein
ModalityBiologic
Therapeutic areaImmunology / Infectious Disease
PhasePhase 3

Mechanism of action

The vaccine uses a replication-incompetent adenovirus serotype 26 (Ad26) as a vector to carry the gene encoding the SARS-CoV-2 spike protein into host cells. Once inside cells, the spike protein is produced and presented to the immune system, triggering both cellular and humoral immune responses. This approach generates antibodies and T-cell responses that protect against SARS-CoV-2 infection.

Approved indications

Common side effects

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Frequently asked questions about Ad26.COV2.S

What is Ad26.COV2.S?

Ad26.COV2.S is a Viral vector vaccine drug developed by National Institute of Allergy and Infectious Diseases (NIAID), indicated for COVID-19 prevention in adults.

How does Ad26.COV2.S work?

Ad26.COV2.S is a viral vector vaccine that delivers genetic instructions for the SARS-CoV-2 spike protein to stimulate immune responses against COVID-19.

What is Ad26.COV2.S used for?

Ad26.COV2.S is indicated for COVID-19 prevention in adults.

Who makes Ad26.COV2.S?

Ad26.COV2.S is developed by National Institute of Allergy and Infectious Diseases (NIAID) (see full National Institute of Allergy and Infectious Diseases (NIAID) pipeline at /company/national-institute-of-allergy-and-infectious-diseases-niaid).

Is Ad26.COV2.S also known as anything else?

Ad26.COV2.S is also known as Janssen COVID-19 Vaccine, JNJ-78436735, JNJ-78436735, VAC31518, Ad26COVS1, JNJ-78436735, Ad26COVS1.

What drug class is Ad26.COV2.S in?

Ad26.COV2.S belongs to the Viral vector vaccine class. See all Viral vector vaccine drugs at /class/viral-vector-vaccine.

What development phase is Ad26.COV2.S in?

Ad26.COV2.S is in Phase 3.

What are the side effects of Ad26.COV2.S?

Common side effects of Ad26.COV2.S include Injection site pain, Fatigue, Headache, Myalgia, Fever.

What does Ad26.COV2.S target?

Ad26.COV2.S targets SARS-CoV-2 spike protein and is a Viral vector vaccine.

Related

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing