This is from the Federal Register, Volume 85, No. 52, dated March 17,2020

"Section IV. Limited Immunity
The Secretary must also state that liability protections available under the PREP Act are in effect with respect to the Recommended Activities. These liability protections provide that, ‘‘[s]ubject to other provisions of [the PREP Act], a covered person shall be immune from suit and liability under federal and state law with respect to all claims for loss caused by, arising out of, relating to, or resulting from the administration to or use by an individual of a covered countermeasure if a Declaration has been issued with respect to such countermeasure.’’ In Section IV of the Declaration, the Secretary states that liability protections are in effect with respect to the Recommended Activities.
Section V. Covered Persons
Section V of the Declaration describes Covered Persons, including Qualified Persons. The PREP Act defines Covered Persons to include, among others, the United States, and those that manufacturer, distribute, administer, prescribe or use Covered Countermeasures. This Declaration includes all persons and entities defined as Covered Persons under the PREP Act (PHS Act 317F–3(i)(2)) as well as others set out in paragraphs (3), (4), (6), (8)(A) and (8)(B).
The PREP Act’s liability immunity applies to ‘‘Covered Persons’’ with respect to administration or use of a Covered Countermeasure. The term ‘‘Covered Persons’’ has a specific meaning and is defined in the PREP Act to include manufacturers, distributors, program planners, and qualified persons, and their officials, agents, and employees, and the United States. The PREP Act further defines the terms ‘‘manufacturer,’’ ‘‘distributor,’’ ‘‘program planner,’’ and ‘‘qualified person’’ as described below.
A manufacturer includes a contractor or subcontractor of a manufacturer; a supplier or licenser of any product, intellectual property, service, research tool or component or other article used in the design, development, clinical testing, investigation or manufacturing of a Covered Countermeasure; and any or all the parents, subsidiaries, affiliates, successors, and assigns of a manufacturer....."
https://www.govinfo.gov/content/pkg/FR-2020-03-17/pdf/2020-05484.pdf