None of the vaccines are live vaccines. The mRNA vaccines (Pfizer, Moderna) are simply mRNA vaccines, which are like temporary notes that tell the cell what to do—in this case, make antibodies to the spike protein of SARS-CoV2.

 The J&J vaccine uses an adenovirus—another type of virus—as a carrier of DNA coding for the spike protein, so the cells can make antibodies to it.  Many have worried about this adenovirus component of the vaccine and if this is a “live” vaccine—but it’s very important to understand that this adenovirus component has had both its replicative and survival abilities erased from its genome.  So it’s really just scaffolding for the DNA coding the spike protein—no live virus involved. It is therefore safe for those patients with suppressed immune systems, either through medications or due to underlying medical conditions.