The Janssen COVID‑19 Vaccine: How It’s Designed
The Janssen COVID-19 Vaccine has not been approved or licensed by the U.S. Food and Drug Administration (FDA), but has been authorized by FDA through an Emergency Use Authorization (EUA) for active immunization to prevent Coronavirus Disease 2019 (COVID-19) in individuals 18 years of age and older. The emergency use of this product is authorized only for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of the medical product under Section 564(b)(1) of the FD&C Act, unless the declaration is terminated or authorization revoked sooner.
Mechanism of Action
The Janssen COVID‑19 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.
Replication-Incompetent Viral Vector Technology1,2
The viral vector used in the Janssen COVID‑19 Vaccine is based on a naturally occurring, low-prevalence human adenovirus. Adenoviruses are known to cause common cold–like symptoms. The deletion of a specific gene renders the adenovirus unable to replicate within humans, transforming it into a delivery vehicle for the genetic material encoding the spike protein of SARS-CoV-2. In this form, the vaccine cannot cause COVID‑19 or adenoviral disease.
Delivery of S Antigen DNA
The viral vector shuttles the gene encoding the S antigen into a human cell.
S Antigen Production
Once inside a cell, the cell’s machinery uses this gene to produce the S antigen and display it on the cell’s surface.
Immune Response to S Antigen
The displayed S antigen triggers an immune response that will help prepare the body to respond to future exposure to SARS-CoV-2.
COVID-19=coronavirus disease 2019; EUA=Emergency Use Authorization; FD&C Act=Federal Food, Drug, and Cosmetic Act; SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.
