FDA Approval of the Pfizer-BioNTech COVID-19 September 17, 2021
Vaccine: Frequently Asked Questions
Kevin J. Hickey
On August 23, 2021, the U.S. Food and Drug Administration (FDA) announced its regulatory
Legislative Attorney
approval of the Pfizer-BioNTech Coronavirus Disease 2019 (COVID-19) vaccine for people 16

years of age or older. The Pfizer-BioNTech vaccine is the first COVID-19 vaccine—and the first
Erin H. Ward
vaccine based on messenger RNA (mRNA) technology—to be licensed by FDA. Previously, the
Legislative Attorney
Pfizer-BioNTech vaccine was available in the United States only under an Emergency Use

Authorization (EUA), a distinct regulatory pathway that allows FDA to authorize use of a drug,
biologic, or medical device prior to approval during a public health emergency.
Agata Bodie
Analyst in Health Policy
Pfizer and BioNTech are marketing their licensed vaccine under the new brand name Comirnaty

(pronounced koe-MIR-na-tee). Comirnaty has the same ingredients and formulation as the Pfizer-
BioNTech vaccine that is authorized under the EUA. The two products differ in branding and

labeling but can be used interchangeably without any impact on safety or effectiveness.
Although Comirnaty is fully approved by FDA for administration to individuals 16 years and older, an EUA remains in effect
for the Pfizer-BioNTech COVID-19 vaccine. Among other things, the reissued EUA authorizes the Pfizer-BioNTech vaccine
for uses that FDA had previously authorized but fall outside the scope of FDA’s approval of Comirnaty. Such uses include
the administration of the vaccine to children aged 12-15 and third doses of the vaccine regimen for certain
immunocompromised individuals. The EUA also authorizes use of Comirnaty for those purposes to allow for interchangeable
administration of the two vaccines.
To encourage rapid development and administration of medical countermeasures during a public health emergency, the
Public Readiness and Emergency Preparedness Act (PREP Act) allows the Secretary of Health and Human Services to
provide liability protections to manufacturers, distributors, and administrators of medical countermeasures. The Secretary
invoked the PREP Act with respect to the COVID-19 pandemic in a declaration effective February 4, 2020. Under the current
PREP Act declaration, manufacturers, distributors, and administrators of COVID-19 vaccines (along with other COVID-19
countermeasures) are generally immune from lawsuits based on injuries relating to the use of the vaccines. Liability
immunity under the PREP Act applies to both licensed and authorized COVID-19 vaccines and thus generally applies in the
same manner to both Comirnaty and the Pfizer-BioNTech vaccine. However, the PREP Act may not protect “off label” uses
of the vaccine—that is, uses covered neither by the EUA nor by the biologics license.
Some employers, businesses, and schools require proof of vaccination for certain activities to protect their employees,
customers, and students from COVID-19. Such “vaccine mandates” take different forms and have largely been sustained
when challenged in court. As a practical matter, FDA’s approval of Comirnaty may result in greater use of vaccine mandates
by these entities to the extent that some of them previously did not require vaccination because no COVID-19 vaccine had
been fully licensed by FDA. FDA’s approval may also diminish uncertainty surrounding the legality of such vaccine
mandates, although the legal authority for and limitations on these mandates are largely the same for both licensed and
authorized vaccines.
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FDA Approval of the Pfizer-BioNTech COVID-19 Vaccine: Frequently Asked Questions

On August 23, 2021, the U.S. Food and Drug Administration (FDA) approved the Coronavirus
Disease 2019 (COVID-19) vaccine manufactured by Pfizer and BioNTech for individuals 16
years of age or older.1 The Pfizer-BioNTech COVID-19 vaccine is the first COVID-19 vaccine—
and the first vaccine based on messenger RNA (mRNA) technology—to be licensed by FDA.2
Pfizer and BioNTech will market their licensed COVID-19 vaccine under the brand name
Comirnaty (pronounced koe-MIR-na-tee).
Prior to approval, the Pfizer-BioNTech vaccine was available in the United States only under an
Emergency Use Authorization (EUA).3 An EUA is a distinct regulatory pathway from the
ordinary biologics licensure pathway that allows FDA to authorize use of a drug or biologic prior
to approval in circumstances such as a public health emergency.4 FDA first issued an EUA for the
Pfizer-BioNTech vaccine on December 11, 2020, and has reissued the EUA several times since
then, such as to authorize the vaccine in additional groups—for example, children 12-15 years of
age.5 A revised EUA remains in effect for the Pfizer-BioNTech vaccine.6
FDA’s approval of Comirnaty has caused some confusion about the scope of FDA’s approval, the
relationship between Comirnaty and the Pfizer-BioNTech COVID-19 vaccine, and other issues.7
This report addresses some common questions about FDA’s approval of Comirnaty.
Frequently Asked Questions
Has the Pfizer-BioNTech COVID-19 vaccine been fully approved by FDA?
Yes. On August 23, 2021, FDA licensed (i.e., approved)8 the first COVID-19 vaccine, Comirnaty,
manufactured by Pfizer-BioNTech. The vaccine is licensed for the prevention of COVID-19,
caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in individuals 16
years of age and older.9

1 FDA, “FDA Approves First COVID-19 Vaccine,” press release, August 23, 2021, https://www.fda.gov/news-events/
press-announcements/fda-approves-first-covid-19-vaccine.
2 FDA, “FDA Approves First COVID-19 Vaccine.”
3 FDA, EUA letter to Pfizer, August 23, 2021, p. 1, https://www.fda.gov/media/150386/download.
4 21 U.S.C. §360bbb-3.
5 FDA, EUA letter to Pfizer, August 23, 2021, pp. 1-2.
6 FDA, EUA letter to Pfizer, August 23, 2021, pp. 1-2.
7 See, for example, Angelo Fichera, “Researcher Distorts Facts on COVID-19 Vaccine Approval, Liability,”
FactCheck.org, August 30, 2021, https://www.factcheck.org/2021/08/scicheck-researcher-distorts-facts-on-covid-19-
vaccine-approval-liability/; Reuters Fact Check, “Fact Check-Media Reports Have Not Lied about Pfizer-BioNTech’s
FDA Approval,” August 27, 2021, https://www.reuters.com/article/factcheck-fda-pfizer/fact-check-media-reports-
have-not-lied-about-pfizer-biontechs-fda-approval-idUSL1N2PY0OL; and Glenn Kessler, “The False Claim That the
Fully-Approved Pfizer Vaccine Lacks Liability Protection,” Washington Post, August 30, 2021,
https://www.washingtonpost.com/politics/2021/08/30/false-claim-that-fully-approved-pfizer-vaccine-lacks-liability-
protection/.
8 Biologics are a subset of drugs and subject to many of the same statutory requirements. However, while small
molecule, chemically synthesized drugs are approved by FDA via a new drug application under the Federal Food,
Drug, and Cosmetic Act, biologics such as vaccines are licensed via a biologics license application under the Public
Health Service Act.
9 FDA, “FDA Approves First COVID-19 Vaccine.” See also FDA, Approval Letter to BioNTech Manufacturing
GmbH, Pfizer Inc., August 23, 2021, https://www.fda.gov/media/151710/download. The approval letter states that
FDA is “issuing Department of Health and Human Services U.S. License No. 2229 to BioNTech Manufacturing
GmbH, Mainz, Germany, under the provisions of section 351(a) of the Public Health Service Act controlling the
manufacture and sale of biological products. The license authorizes you to introduce or deliver for introduction into
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FDA Approval of the Pfizer-BioNTech COVID-19 Vaccine: Frequently Asked Questions

To obtain licensure from FDA, BioNTech Manufacturing GmbH, in partnership with Pfizer,
submitted a biologics license application (BLA) to the agency for review. The BLA for Comirnaty
included clinical trial safety and effectiveness data and other information that built on data
previously submitted to FDA in Pfizer-BioNTech’s November 2020 EUA request for the Pfizer-
BioNTech COVID-19 vaccine.10
FDA received the BLA on May 18, 2021.11 The agency granted the BLA priority review,
assigning it a review goal date of January 16, 2022. FDA also had previously designated the
vaccine as a fast track product.12 Fast track designation may be granted to a vaccine that is
intended to prevent a serious disease or condition and for which nonclinical or clinical data
demonstrate the product’s potential to address an unmet medical need.13 The designation confers
certain benefits, such as expedited review and eligibility for rolling review, meaning that FDA
may review portions of the BLA before the completed application is submitted.14 FDA issued its
decision to license Comirnaty in 97 days, or about three months after receiving the complete BLA
from Pfizer-BioNTech.15
What is Comirnaty?
Comirnaty is the proprietary name (i.e., the brand name) under which the FDA-licensed vaccine
that has been known as the Pfizer-BioNTech COVID-19 vaccine (or BNT162b2) will be
marketed.16 The proprietary name is the exclusive name of a drug or vaccine that is owned by a
company under trademark law. Pharmaceutical products are often marketed under a brand name,
which the company selects and FDA approves as part of the BLA review process.17 In the BLA
approval letter, FDA indicated that Pfizer and BioNTech may label and market the licensed
vaccine as Comirnaty,18 which, according to the companies, “represents a combination of the
terms COVID-19, mRNA, community, and immunity.”19

interstate commerce, those products for which your company has demonstrated compliance with establishment and
product standards.”
10 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
11 FDA, Summary Basis for Regulatory Action—Comirnaty, p. 5, https://www.fda.gov/media/151733/download.
12 FDA, Summary Basis for Regulatory Action—Comirnaty, p. 5.
13 21 U.S.C. §356(b). FDA, “Guidance for Industry Expedited Programs for Serious Conditions—Drugs and
Biologics,” May 2014, p. 9, https://www.fda.gov/media/86377/download.
14 21 U.S.C. §356(d). FDA, “Guidance for Industry Expedited Programs for Serious Conditions—Drugs and
Biologics,” p. 10.
15 FDA, “First COVID-19 Vaccine Approval Media Call,” August 23, 2021, at 19:05 minutes.
16 FDA, Summary Basis for Regulatory Action—Comirnaty, p. 3; FDA, “Comirnaty and Pfizer-BioNTech COVID-19
Vaccine,” accessed August 27, 2021, https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-
2019-covid-19/comirnaty-and-pfizer-biontech-covid-19-vaccine; and Pfizer, “Pfizer and BioNTech Receive
Authorization in the European Union for COVID-19 Vaccine,” December 21, 2020, https://www.pfizer.com/news/
press-release/press-release-detail/pfizer-and-biontech-receive-authorization-european-union.
17 FDA, “Contents of a Complete Submission for the Evaluation of Proprietary Names,” Guidance for Industry, April
2016, pp. 5-7, https://www.fda.gov/media/72144/download.
18 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
19 Pfizer, “Pfizer and BioNTech Receive Authorization in the European Union for COVID-19 Vaccine,” press release,
December 21, 2020, https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-receive-
authorization-european-union.
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What is the scope of FDA’s biologics license for Comirnaty?
Comirnaty is licensed as a two-dose vaccine for the prevention of COVID-19 in individuals 16
years of age and older. It is not licensed for use in individuals under 16 years of age. It is also not
licensed to be administered as a third dose to individuals who are immunocompromised. The
EUA for the Pfizer-BioNTech COVID-19 vaccine, however, does cover these uses, as explained
below in the section “What is the scope of the current EUA for the Pfizer-BioNTech vaccine?”
In determining whether to license a vaccine for a specific use, FDA reviews the data and
information submitted by the manufacturer in the BLA and inspects the facilities in which a
vaccine is made to ensure that the product meets standards for safety, purity, and potency (i.e.,
effectiveness).20 The scope of Comirnaty’s licensure is based on the supporting data and
information FDA received in Pfizer-BioNTech’s BLA. This support included data regarding the
safety and effectiveness of two doses of the vaccine administered in individuals 16 years of age
and older, building on the data and information previously submitted by the companies in their
initial EUA request.
For example, the Pfizer-BioNTech COVID-19 vaccine EUA was granted based on safety and
effectiveness data derived from an ongoing, randomized, controlled, and blinded trial of
approximately 36,000 individuals 16 years of age and older who did not have evidence of SARS-
CoV-2 infection within a week of receiving the second dose of the vaccine. About half of this
group received the vaccine (n=18,198) and the other half placebo (n=18,325).21 The vaccine was
found to be 95% effective at preventing symptomatic COVID-19, with eight cases of COVID-19
identified in the vaccine group and 162 in the placebo group.22
FDA evaluated follow-up data from this trial as part of the Comirnaty BLA, with the updated
analysis including approximately 19,993 individuals in the vaccine group and 20,118 in the
placebo group.23 The updated analysis found an effectiveness rate of 91%, based on the
occurrence of 77 cases of COVID-19 in the vaccine group and 833 COVID-19 cases in the
placebo group.24 In determining whether to license the vaccine, FDA evaluated these data, along
with information about the manufacturing facilities, longer term follow-up safety data from the
trial, adverse events reported from use of the vaccine under EUA, and other information.
Under the terms of licensure, Comirnaty may be manufactured only in facilities identified and
approved under the vaccine’s BLA.25 Comirnaty’s labeling must be identical to that approved by
FDA and must include warnings and precautions, contraindications, dosage and administration
instructions, and storage and handling conditions, among other information.26 The Comirnaty
approval letter also requires that any manufacturing changes that deviate from those approved

20 42 U.S.C. §262(a)(1)(C).
21 FDA, “Q&A for Comirnaty (COVID-19 Vaccine mRNA),” accessed August 30, 2021, https://www.fda.gov/
vaccines-blood-biologics/qa-comirnaty-covid-19-vaccine-mrna. See also FDA, EUA letter to Pfizer, December 11,
2020, p. 23, https://www.fda.gov/media/144416/download.
22 FDA, EUA letter to Pfizer, December 11, 2020, p. 23.
23 FDA, “Q&A for Comirnaty (COVID-19 Vaccine mRNA);” and FDA, Summary Basis for Regulatory Action—
Comirnaty, p. 19.
24 FDA, “Q&A for Comirnaty (COVID-19 Vaccine mRNA);” and FDA, Summary Basis for Regulatory Action—
Comirnaty, p. 19.
25 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
26 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer. A vaccine manufacturer must submit proposed
vaccine labeling as part of a BLA. See 21 C.F.R. §601.14. Labeling requirements for drugs and biologics are specified
in 21 C.F.R. §§201.56, 201.57, for example.
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under the BLA be submitted to FDA, specifies requirements for advertising and promotional
labeling, and outlines postmarketing study obligations for the manufacturer.27
As required for all licensed vaccines, Pfizer and BioNTech must report adverse events associated
with Comirnaty to FDA.28 Each serious and unexpected adverse experience must be reported as
soon as possible but no later than 15 days from initial receipt of the information by the
manufacturer.29 Periodic safety reports are required for each adverse experience not reported in a
15-day alert report and must be submitted to FDA at quarterly intervals for the first three years
following approval and at annual intervals thereafter.30
Is there any difference between Comirnaty and the Pfizer-BioNTech vaccine?
The BLA-licensed vaccine Comirnaty is the same formulation as the EUA-authorized Pfizer-
BioNTech COVID-19 vaccine. Specifically, both Comirnaty and the Pfizer-BioNTech vaccine
contain “a nucleoside-modified messenger RNA (mRNA) encoding the viral spike glycoprotein
(S) of SARSCoV-2” formulated in the same lipids (i.e., organic compounds that are insoluble in
water such as fats).31 Because the vaccines contain the same formulation, doses distributed under
the EUA can be used interchangeably with doses licensed under the BLA without safety or
effectiveness concerns.32 The distinction between Comirnaty and the Pfizer-BioNTech COVID-19
vaccine is legal rather than scientific, as further discussed in the section “Why did FDA refer to
Comirnaty and the Pfizer-BioNTech vaccine as “legally distinct”?”
If Comirnaty is now licensed, why did FDA reissue an EUA for the Pfizer-
BioNTech vaccine?
There are several reasons FDA reissued the Pfizer-BioNTech vaccine EUA when it licensed the
Comirnaty vaccine under the BLA. FDA stated that it reissued the EUA “to clarify that the EUA
will remain in place for the Pfizer-BioNTech COVID-19 vaccine for the previously-authorized
indication and uses, and to authorize use of COMIRNATY (COVID-19 Vaccine, mRNA) under
this EUA for certain uses that are not included in the approved BLA.”33 Reissuing the EUA has
several legal and practical effects.
First, the EUA allows the Pfizer-BioNTech vaccine and Comirnaty to be used for patient
populations and clinical situations that are not included in the Comirnaty BLA.34 FDA approved
Comirnaty to be marketed only for a two-dose regimen for individuals 16 years of age and
older.35 The EUA authorizes both the Pfizer-BioNTech vaccine and Comirnaty to be used for a
two-dose regimen for individuals 12-15 years of age and for certain immunocompromised
individuals to receive a third dose of the vaccine.36 Without the EUA, individuals 12-15 years of

27 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
28 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
29 21 C.F.R §600.80(c).
30 21 C.F.R §600.80(c).
31 FDA, Summary Basis for Regulatory Action—Comirnaty, p. 3; and FDA, EUA letter to Pfizer, December 11, 2020,
p. 11.
32 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
33 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
34 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
35 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer.
36 FDA, EUA letter to Pfizer, August 23, 2021, pp. 5-6.
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age would not be authorized or approved to receive a Pfizer-manufactured COVID-19 vaccine,
nor could the applicable immunocompromised individuals receive a third shot. (For a summary of
the populations covered by the EUA and the approved BLA, see Table 1.)
Second, reissuing the EUA allows vaccine administrators to use the remaining doses of the
Pfizer-BioNTech vaccine that have not yet been administered. FDA notes in the EUA that there
“remains a significant amount of Pfizer-BioNTech COVID-19 vaccine that was manufactured and
labeled in accordance with” the EUA. The Pfizer-BioNTech vaccine has the same formulation as
Comirnaty but is legally distinct and can be manufactured, marketed, distributed, and
administered only pursuant to the EUA.37 (For more information on what it means for the two
vaccines to be legally distinct, see “Why did FDA refer to Comirnaty and the Pfizer-BioNTech
vaccine as “legally distinct”?”) If FDA had revoked the EUA when it approved the Comirnaty
BLA, the remaining Pfizer-BioNTech vaccine doses would have been unauthorized and unable to
be used.
Third, the EUA facilitates the logistics of distributing and administering Pfizer-manufactured
COVID-19 vaccines. The EUA authorizes use of Comirnaty for the patient populations and
clinical situations for which the Pfizer-BioNTech vaccine is authorized but that are not covered
by the BLA: a two-dose regimen for individuals 12-15 years of age and a third dose for certain
immunocompromised individuals.38 By authorizing Comirnaty for these uses, and clarifying that
Comirnaty is interchangeable with the Pfizer-BioNTech vaccine, the EUA allows vaccine
administrators to use whichever vaccine is available—whether it is labeled Comirnaty or Pfizer-
BioNTech—which may avoid potential shortages or other logistical complications.39
Table 1. Comparison of Patient Populations Covered by the Pfizer-BioNTech EUA
and Comirnaty BLA
Pfizer-BioNTech EUA
Comirnaty BLA
Patient Population
Pfizer-BioNTech
Comirnaty

Individuals 0-11
x
x
x
Individuals 12-15
√
√
x
Individuals 16 and older
√
x
√
Third dose for certain
immunocompromised individuals
√
√
x
Source: CRS.
Note: EUA = Emergency Use Authorization; BLA = biologics license application.
What is the scope of the current EUA for the Pfizer-BioNTech vaccine?
The Pfizer-BioNTech vaccine EUA, as reissued on August 23, 2021, authorizes a two-dose
regimen of the Pfizer-BioNTech vaccine for individuals 12 years or age and older and a third dose
of the Pfizer-BioNTech vaccine for individuals 12 years or age and older who have undergone
solid organ transplants or been diagnosed with similarly immunocompromising conditions.40 The

37 FDA, EUA letter to Pfizer, August 23, 2021; 42 U.S.C. §360bbb-3.
38 FDA, EUA letter to Pfizer, August 23, 2021, p. 6.
39 FDA, EUA letter to Pfizer, August 23, 2021, pp. 2 and 6.
40 FDA, EUA letter to Pfizer, August 23, 2021, pp. 5-6. The August 23, 2021, EUA revises the existing EUA, which
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EUA also authorizes a two-dose regimen of Comirnaty for individuals 12-15 years of age and a
third dose of Comirnaty for individuals 12 years or age and older who have undergone solid
organ transplants or have been diagnosed with similarly immunocompromising conditions.41
These uses are not included in the approved Comirnaty BLA (see “What is the scope of FDA’s
biologics license for Comirnaty?”).
The scope of the Pfizer-BioNTech vaccine EUA is based on the supporting data and information
submitted to FDA by the companies in their EUA requests. As FDA has received additional data
to support that the vaccine may be effective in preventing COVID-19 in certain pediatric
populations (i.e., 12-15 year olds) and under expanded dosing regimens (i.e., a third dose for
certain immunocompromised individuals), the agency has amended and reissued the original
Pfizer-BioNTech vaccine EUA to include these indications.
FDA initially granted the Pfizer-BioNTech vaccine EUA on December 11, 2020, based on safety
and effectiveness data in individuals 16 years of age and older.42 FDA subsequently reissued the
EUA on May 10, 2021, to authorize the use of the vaccine in individuals 12-15 years of age based
on clinical trial safety and effectiveness data in more than 2,000 individuals in this age group.43
FDA again amended the Pfizer-BioNTech vaccine EUA on August 12, 2021, as requested by
Pfizer, to allow for the use of a third dose of the vaccine in certain immunocompromised
individuals based on safety and effectiveness data in the published literature.44
On August 23, 2021, FDA reissued the EUA after it approved the Comirnaty BLA “to clarify that
the EUA will remain in place for the Pfizer-BioNTech COVID-19 vaccine for the previously-
authorized indication and uses, and to authorize use of COMIRNATY (COVID-19 Vaccine,
mRNA) under this EUA for certain uses that are not included in the approved BLA.”45 Under the
terms of the EUA, the Pfizer-BioNTech vaccine may be manufactured only in a facility identified
and agreed upon in Pfizer’s EUA request.46 The Pfizer-BioNTech vaccine vial label and carton
labels must be clearly marked for “Emergency Use Authorization.”47 Pfizer must distribute the
Pfizer-BioNTech vaccine to emergency response stakeholders directly or through authorized
distributors as directed by the U.S. government, such as the Centers for Disease Control and
Prevention (CDC).48 The Pfizer-BioNTech vaccine must be administered by vaccine providers, as

FDA originally issued for the Pfizer-BioNTech vaccine on December 11, 2020, for individuals 16 years of age or older.
FDA, EUA letter to Pfizer, December 11, 2020. Since the initial EUA, FDA has amended the EUA several times and
issued two additional decision memoranda. The first, issued May 10, 2021, authorized the Pfizer-BioNTech vaccine to
be used in individuals 12-15 years of age. FDA, EUA letter to Pfizer, May 10, 2021, https://www.fda.gov/media/
148542/download. The second, issued August 12, 2021, authorized a third dose of the Pfizer-BioNTech vaccine to be
administered to individuals who have undergone solid organ transplants or have been diagnosed with similarly
immunocompromising conditions. FDA, EUA letter to Pfizer, August 12, 2021, https://www.fda.gov/media/151613/
download.
41 FDA, EUA letter to Pfizer, August 23, 2021, pp. 5-6.
42 FDA, EUA letter to Pfizer, December 11, 2020.
43 FDA, EUA letter to Pfizer, May 10, 2021.
44 FDA, EUA letter to Pfizer, August 12, 2021.
45 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
46 FDA, EUA letter to Pfizer, August 23, 2021, p. 7.
47 FDA, EUA letter to Pfizer, August 23, 2021, p. 7.
48 FDA, EUA letter to Pfizer, August 23, 2021, pp. 5-6. Pfizer and the U.S. government determine which entities are
“authorized distributor(s).” FDA, EUA letter to Pfizer, August 23, 2021, p. 5, n.11. The letter defines emergency
response stakeholder as public health agencies and their delegates. FDA, EUA letter to Pfizer, August 23, 2021, p. 5, n.
12.
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defined by the EUA.49 Fact sheets must be made available to vaccination providers and
recipients.50
The EUA imposes reporting requirements on Pfizer in connection with adverse events.51 It also
imposes conditions on emergency response stakeholders and vaccination providers to distribute
and administer the Pfizer-BioNTech vaccine in accordance with the EUA’s terms and to provide
relevant information to stakeholders and recipients.52 The EUA further provides conditions
related to advertising, promoting, and exporting the Pfizer-BioNTech vaccine.53 Finally, the EUA
requires that Comirnaty vaccines be manufactured, distributed, and administered in accordance
with the EUA terms when administered for uses authorized by the EUA (i.e., for individuals 12-
15 years or age and third doses for certain immunocompromised individuals), except that
Comirnaty vaccines manufactured and labeled in accordance with the BLA are deemed to meet
the EUA’s manufacturing, labeling, and distribution requirements.54
Unlike the BLA, which will remain in effect indefinitely unless it is withdrawn for safety or
efficacy reasons, the EUA remains in effect only until the Secretary revokes the declaration that
an emergency exists due to the COVID-19 pandemic that justifies the emergency use of
unapproved drugs and biological products.55
Can COVID-19 vaccine providers use the Comirnaty-labeled vaccine
interchangeably with the Pfizer-BioNTech vaccine?
Yes. The revised EUA states that Comirnaty can be used interchangeably with the Pfizer-
BioNTech vaccine because it is the same formulation.56 This means vaccine administrators may
use Comirnaty for the first dose and Pfizer-BioNTech vaccine for the second dose, or vice versa,
“without presenting any safety or effectiveness concerns.”57 Similarly, either the Comirnaty or

49 FDA, EUA letter to Pfizer, August 23, 2021, p. 6. As defined in the EUA, for vaccines administered in the United
States, a vaccination provider is “a facility, organization, or healthcare provider licensed or otherwise authorized by the
emergency response stakeholder … to administer or provide vaccination services” and “who is enrolled in the CDC
COVID-19 Vaccination Program.” FDA, EUA letter to Pfizer, August 23, 2021, p. 6, n. 13.
50 Specifically, vaccination providers must be provided with a fact sheet titled “Fact Sheet for Healthcare Providers
Administering Vaccine (Vaccine Providers): Emergency Use Authorization (EUA) of Pfizer-BioNTech COVID-19
Vaccine to Prevent Coronavirus Disease 2019 (COVID-19).” Vaccine recipients must be provided with a fact sheet
titled “Vaccine Information Fact Sheet for Recipients and Caregivers About COMIRNATY (COVID-19 Vaccine,
mRNA) and Pfizer-BioNTech COVID-19 Vaccine to Prevent Coronavirus Disease (COVID-19).” FDA, EUA letter to
Pfizer, August 23, 2021, p. 7.
51 FDA, EUA letter to Pfizer, August 23, 2021, p. 9.
52 FDA, EUA letter to Pfizer, August 23, 2021, pp. 10-11.
53 FDA, EUA letter to Pfizer, August 23, 2021, pp. 11-12.
54 FDA, EUA letter to Pfizer, August 23, 2021, p. 12.
55 FDA, EUA letter to Pfizer, August 23, 2021, p. 13; 42 U.S.C. §300bbb-3.
56 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
57 FDA, EUA letter to Pfizer, August 23, 2021, p. 2, n. 8. In the context of biological products, the standard for
interchangeability is that (1) the biological product is biosimilar to the reference (i.e., brand-name) product; (2) the
biological product can be expected to produce the same clinical result in any given patient as the reference product; and
(3) if administered more than once to an individual (as the Pfizer-BioNTech and Comirnaty vaccines are due to the
two-dose regimen), the risk of safety and diminished efficacy from switching between the biosimilar and reference
product is not greater than when using the reference product alone. 42 U.S.C. §262(k)(4). FDA appears to have used
the same standard to determine that the Comirnaty and Pfizer-BioNTech vaccines are interchangeable.
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Pfizer-BioNTech vaccine may be used for any third doses regardless of which vaccine was used
for the original two-dose regimen.
Why did FDA refer to Comirnaty and the Pfizer-BioNTech vaccine as “legally
distinct”?
In the EUA, FDA states that the Comirnaty and Pfizer-BioNTech vaccines “are legally distinct
with certain differences that do not impact safety or effectiveness.”58 While the Comirnaty and
Pfizer-BioNTech vaccines have the same formulation, they are legally allowed to be marketed
and used pursuant to different legal authorities.59 Specifically, Comirnaty is licensed pursuant to a
BLA issued under the Public Health Service (PHS) Act (42 U.S.C. §262).60 The Pfizer-BioNTech
vaccine is authorized for emergency use pursuant to the Federal Food, Drug, and Cosmetic
(FD&C) Act (21 U.S.C. §360bbb-3).61
Each product must be manufactured, labeled, marketed, distributed, and administered in
accordance with the requirements of the legal regime under which it was approved or authorized.
These requirements may differ in a number of ways. For example, under the EUA, the Pfizer-
BioNTech vaccine must be accompanied by fact sheets for the vaccine administrator and recipient
informing them, among other things, of the product’s emergency authorization, known and
anticipated risks and benefits, and the right to decline the vaccine.62 Comirnaty need not be
accompanied by this information if it is being administered pursuant to the BLA rather than the
EUA; instead, the PHS Act and other FDA regulatory labeling requirements apply.63
As another example, the Pfizer-BioNTech vaccine may be manufactured only at facilities
identified and agreed upon in Pfizer’s EUA request, must be distributed directly by Pfizer or
through authorized distributors to emergency response stakeholders (as defined in the EUA) as
directed by the U.S. government, and must be administered by vaccination providers (as defined
in the EUA) only to individuals 12 years of age and older.64 These limitations do not apply to
Comirnaty vaccines manufactured and distributed pursuant to the BLA; instead, the PHS Act and
FD&C Act requirements apply. Comirnaty may be manufactured only at facilities identified and
approved in the BLA.65
What liability protections apply to COVID-19 vaccines?
Under the Public Readiness and Emergency Preparedness Act (PREP Act), the Secretary of
Health and Human Services (HHS) has the authority to limit legal liability for losses relating to
the administration of medical countermeasures—such as diagnostics, treatments, and vaccines—

58 FDA, EUA letter to Pfizer, August 23, 2021, p. 2, n. 8.
59 FDA, EUA letter to Pfizer, August 23, 2021, p. 2.
60 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer, August 23, 2021; 42 U.S.C. §262.
61 FDA, EUA letter to Pfizer, August 23, 2021.
62 FDA, EUA letter to Pfizer, August 23, 2021, p. 7; FDA, “Fact Sheet for Healthcare Providers Administering Vaccine
(Vaccination Providers): Emergency Use Authorization (EUA) of Pfizer-BioNTech COVID-19 Vaccine to Prevent
Coronavirus Disease 2019 (COVID-2019),” August 23, 2021, https://www.fda.gov/media/144413/download; FDA,
“Vaccine Information Fact Sheet for Recipients and Caregivers About Comirnaty (COVID-19 Vaccine, mRNA) and
Pfizer BioNTech COVID-19 Vaccine to Prevent Coronavirus Disease (COVID-19),” August 23, 2021,
https://www.fda.gov/media/144414/download.
63 FDA, EUA letter to Pfizer, August 23, 2021, p. 12.
64 FDA, EUA letter to Pfizer, August 23, 2021, pp. 5-7.
65 FDA, Approval Letter to BioNTech Manufacturing GmbH, Pfizer, August 23, 2021.
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during a public health emergency.66 In a declaration effective February 4, 2020, the Secretary
invoked the PREP Act and declared COVID-19 to be a public health emergency warranting
liability protections for manufacturers, distributors, and administrators of covered
countermeasures (along with other covered persons).67 If covered by the terms of such a
declaration, the PREP Act generally immunizes a covered person from legal liability for all
claims for loss relating to the administration or use of a covered countermeasure.68
Under the current PREP Act declaration for COVID-19, covered countermeasures include “any
drug, any biologic … or any vaccine manufactured, used, designed, [or] developed … [t]o
diagnose, mitigate, prevent, treat, or cure COVID-19.”69 Covered persons include manufacturers,
distributors, and qualified persons authorized to administer covered countermeasures by federal,
state, tribal, and local public health agencies.70
Thus, vaccine manufacturers, distributors, and authorized health care providers administering the
Pfizer-BioNTech COVID-19 vaccine or Comirnaty are generally immune from legal claims for
injury or other losses resulting from the administration of the vaccine.71 For example, an
individual who suffers an adverse allergic reaction to a COVID-19 vaccine—such as the rare
reported cases of anaphylaxis72—generally cannot sue the vaccine manufacturer for damages
resulting from the injury. Instead, while the declared public health emergency remains in effect,
monetary compensation for any deaths or serious injuries caused by COVID-19 vaccines may be
available from the federal government through the Countermeasures Injury Compensation
Program.73

66 42 U.S.C. §§247d-6d, 247d-6e. For more detail on the scope of liability protections for COVID-19 countermeasures
under the PREP Act, see generally CRS Legal Sidebar LSB10443, The PREP Act and COVID-19: Limiting Liability
for Medical Countermeasures, by Kevin J. Hickey.
67 HHS, “Declaration Under the Public Readiness and Emergency Preparedness Act for Medical Countermeasures
Against COVID-19,” 85 Federal Register 15198, March 10, 2020. The PREP Act declaration has been subsequently
amended nine times to expand the scope of its liability protection in various ways. See HHS, “Public Readiness and
Emergency Preparedness Act,” accessed September 8, 2021, https://www.phe.gov/Preparedness/legal/prepact/Pages/
default.aspx (linking to the PREP Act declaration amendments).
68 42 U.S.C. §247d-6d(a)(1).
69 HHS, “Fourth Amendment to the Declaration Under the Public Readiness and Emergency Preparedness Act for
Medical Countermeasures Against COVID-19 and Republication of the Declaration,” 85 Federal Register 79190,
79196, December 3, 2020. (Subsequent amendments have not altered this section of the declaration.)
70 HHS, “Ninth Amendment to Declaration Under the Public Readiness and Emergency Preparedness Act for Medical
Countermeasures Against COVID-19,” 86 Federal Register 51160, 51163, September 14, 2021.
71 42 U.S.C. §247d-6d(a)(1); see generally CRS Report R46399, Legal Issues in COVID-19 Vaccine Development and
Deployment, by Kevin J. Hickey, Wen W. Shen, and Erin H. Ward, at pp. 32-36. The “sole exception to the immunity”
is a claim for willful misconduct. See 42 U.S.C. §247d-6d(d)(1). “Willful misconduct” as defined in the PREP Act
requires that the covered person acted (i) intentionally to achieve a wrongful purpose; (ii) knowingly without legal or
factual justification; and (iii) in disregard of a known or obvious risk that is so great as to make it highly probable that
the harm will outweigh the benefit. 42 U.S.C. §247d-6d(c)(1)(A).
72 CDC and FDA, “Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech
COVID-19 Vaccine—United States, December 14-23,” Morbidity and Mortality Weekly Report, vol. 70, no. 2 (January
15, 2021), pp. 46-51, https://www.cdc.gov/mmwr/volumes/70/wr/mm7002e1.htm.
73 Health Resources and Services Administration, “Countermeasures Injury Compensation Program,” accessed
September 8, 2021, https://www.hrsa.gov/cicp; see generally CRS Legal Sidebar LSB10584, Compensation Programs
for Potential COVID-19 Vaccine Injuries, by Kevin J. Hickey and Erin H. Ward.
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Does FDA’s licensure of Comirnaty affect liability protections for COVID-19
vaccines under the PREP Act?
Generally speaking, it does not. Under the PREP Act, “covered countermeasures” include both
(1) “qualified pandemic or epidemic products” and (2) biological products authorized for
emergency use under an EUA.74
Comirnaty is a biological product licensed by FDA to prevent COVID-19 (see “What is the scope
of FDA’s biologics license for Comirnaty?”). It meets the definition of qualified pandemic or
epidemic product and is thus a covered countermeasure under the PREP Act while the PREP Act
declaration remains in effect. For its part, the Pfizer-BioNTech vaccine is authorized under an
EUA to prevent COVID-19 (see “What is the scope of the current EUA for the Pfizer-BioNTech
vaccine?”). It, too, meets the definition of covered countermeasure under the PREP Act.
Because Comirnaty and the Pfizer-BioNTech COVID-19 vaccine are both covered
countermeasures, the liability protections under the PREP Act apply to both products. That is,
assuming that all the other elements for immunity under the PREP Act are met,75 whether the
vaccine’s use is licensed by FDA or authorized under an EUA does not affect the PREP Act’s
liability protections.
Do the PREP Act’s liability protections extend to off-label uses of Comirnaty?
It is not clear whether off-label uses of otherwise covered countermeasures, such as Comirnaty,
would receive the same liability protections under the PREP Act as authorized and approved uses.
Off-label use generally refers to the practice of prescribing or administering a drug or biologic
(such as a vaccine) for a use other than the one or more specific uses FDA approved.76 Such off-
label uses are generally considered to be within the scope of the practice of medicine, with the
physician exercising professional judgment about treatment, and therefore not in violation of the
FD&C Act’s marketing restrictions.77
Following the licensure of Comirnaty, there were reports of parents expressing interest in
vaccinating their younger children who are not covered by the scope of the licensed vaccine or
the EUA-authorized vaccine (i.e., children under 12 years of age) through off-label use of
Comirnaty.78 The CDC has noted that such uses of Comirnaty are not authorized and indicated
that off-label uses therefore “may not be covered” under the PREP Act.79

74 42 U.S.C. §247d-6d(i)(1)(A), (C). A “qualified pandemic product” is defined to include a “biological product that is
… manufactured, used, designed, [or] developed … to diagnose, mitigate, prevent, treat, or cure a pandemic or
epidemic” and that is approved or licensed by FDA. 42 U.SC. §247d-6d(i)(7)(A)-(B).
75 See CRS Legal Sidebar LSB10443, The PREP Act and COVID-19: Limiting Liability for Medical Countermeasures,
by Kevin J. Hickey, for a discussion of those other elements (such as the claim being against a “covered person” and a
causal relationship between the loss and the use of the covered countermeasure).
76 FDA, “Understanding Unapproved Use of Approved Drugs ‘Off Label,’” accessed September 1, 2021,
https://www.fda.gov/patients/learn-about-expanded-access-and-other-treatment-options/understanding-unapproved-
use-approved-drugs-label.
77 See, for example, Buckman Co. v. Plaintiffs’ Legal Comm., 531 U.S. 341, 350 (2001).
78 See, for example, Theresa Gaffney, “‘Tired of Worrying’: As Some Parents Press for Vaccines Off-Label,
Pediatricians Call for Patience,” STAT News, August 27, 2021, https://www.statnews.com/2021/08/27/covid19-
vaccine-off-label-kids/.
79 CDC, “COVID-19 Vaccine FAQs for Healthcare Professionals” (see section “Off-Label Use”), accessed August 30,
2021, https://www.cdc.gov/vaccines/covid-19/hcp/faq.html#off-label-use.
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The CDC’s statement reflects legal uncertainty as to whether PREP Act immunity extends to
claims for injuries resulting from off-label uses of a covered countermeasure. For immunity under
the PREP Act to apply, the activity at issue must relate to the administration or use of a covered
countermeasure for which the Secretary of HHS has issued a PREP Act declaration.80 If providers
knowingly administer vaccines to populations currently outside of the EUA or the approved
biologics license for Comirnaty, they would arguably fall outside of the current PREP Act
declaration and therefore not be immunized from liability. In particular, the declaration contains
language excluding uses that exceed the scope of authorization by the relevant public health
authority. For example, the declaration states that “liability protections are afforded to Covered
Persons only for” covered countermeasures that (1) “are related to activities authorized in
accordance with the public health and medical response of the Authority Having Jurisdiction” or
(2) are administered “pursuant to the FDA licensure, approval, clearance, or authorization.”81 The
“Authority Having Jurisdiction” refers to the state, federal, tribal, or local “public agency … that
has legal responsibility and authority for responding to an incident.”82 Thus, if providers
intentionally engage in activities that the relevant public health authorities—here, the CDC and
FDA—did not authorize, they may not be immune from claims of legal liability under the PREP
Act declaration for those actions.
Off-label use generally refers to a situation where the provider exercises professional judgment to
prescribe or administer a drug or biologic for an unapproved use. A potentially distinct scenario
may occur when an otherwise-authorized health care provider unknowingly administers the
vaccine to a recipient outside of the currently authorized population. For example, anecdotal
media reports indicate instances of parents misrepresenting the ages of their children to obtain
COVID-19 vaccines.83 In that situation, the health care provider administering the vaccine may
have no reason to know that the vaccine administration was unauthorized under the EUA and
current CDC guidance.
Language in the PREP Act declaration arguably allows health care providers to retain legal
immunity in this situation. The current PREP Act declaration purports to provide immunity even
if the vaccine recipient is outside the covered population if the “qualified person reasonably could
have believed the recipient was in this population.”84 The PREP Act declaration would therefore
arguably reach authorized health care providers who unwittingly administer COVID-19 vaccines
to populations beyond those currently authorized. As the former general counsel of HHS
explained in an advisory opinion (later explicitly incorporated into the operative PREP Act
declaration85), PREP Act immunity should apply to persons who “reasonably could have
believed” they were covered persons administering a covered countermeasure, even if that belief

80 42 U.S.C. §247d-6d(a)(1), (b)(1).
81 HHS, “Fourth Amendment to the Declaration Under the Public Readiness and Emergency Preparedness Act for
Medical Countermeasures Against COVID-19 and Republication of the Declaration.” There are other covered activities
and distribution channels in the PREP Act declaration—such as activities relating to federal contracts—but these do not
appear relevant to the off-label use scenario.
82 HHS, “Fourth Amendment to the Declaration Under the Public Readiness and Emergency Preparedness Act for
Medical Countermeasures Against COVID-19 and Republication of the Declaration,” at 79197.
83 See, for example, Brett Kast, “Some Michigan Parents Reportedly Lying About Their Child’s Age to Get Them
COVID Vaccine,” WXYZ, August 18, 2021, https://www.wxyz.com/news/coronavirus/covid-19-vaccine/some-
michigan-parents-reportedly-lying-about-their-childs-age-to-get-them-covid-vaccine.
84 HHS, “Fourth Amendment to the Declaration Under the Public Readiness and Emergency Preparedness Act for
Medical Countermeasures Against COVID-19 and Republication of the Declaration.”
85 HHS, “Fourth Amendment to the Declaration Under the Public Readiness and Emergency Preparedness Act for
Medical Countermeasures Against COVID-19 and Republication of the Declaration” at 79195, n. 19.
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later proved mistaken.86 Given the limited case law on the PREP Act, however, it is difficult to
determine whether a court would agree with these constructions of the PREP Act declaration and
statute.87
Separately from the PREP Act issue, the CDC has stated that knowing off-label uses “would be in
violation of the CDC COVID-19 Vaccination Program provider agreement and therefore may not
be reimbursable, and may impact the ability of a provider to remain in the CDC Program, in
addition to other potential sanctions.”88 Thus, whether or not PREP Act immunity applies,
providers engaging in intentional off-label use may be in violation of their contractual
obligations.
The FDA’s vaccine advisory committee, the Vaccines and Related Biological Products Advisory
Committee (VRBPAC), may ultimately recommend authorizing additional uses for the Pfizer-
BioNTech and other COVID-19 vaccines—such as administration of the vaccine to children aged
5-11 or booster shots for the general adult population. FDA would then likely reissue the
currently operative EUA to authorize these additional uses. At that point, such uses would no
longer be off-label but within the scope of an EUA and covered by the PREP Act.
Does FDA’s licensure of Comirnaty affect the authority of employers or
schools to “mandate” COVID-19 vaccines?
As explained in more detail in other CRS products, federal law does not generally preclude
private employers from requiring that their employees be vaccinated but may require these
entities to provide appropriate exemptions based on medical disabilities or religious beliefs.89 As
to government employers and public schools, modern courts have relied on Jacobson v.
Massachusetts—a 1905 Supreme Court ruling holding that the Constitution does not preclude
state governments from mandating vaccination90—to uphold such vaccine mandates (with

86 HHS, “Advisory Opinion on the Public Readiness and Emergency Preparedness Act and the March 10, 2020
Declaration under the Act,” May 19, 2020, p. 2, https://www.hhs.gov/guidance/sites/default/files/ hhs-guidance-
documents/prep-act-advisoryopinion-hhs-ogc.pdf. HHS’s interpretation draws on the statutory provision that provides
immunity under “circumstances in which … the covered person reasonably could have believed that the
countermeasure was administered or used in accordance with” population or geographical limitations in the PREP Act
Declaration. 42 U.S.C. §247d-6d(a)(4)(B).
87 For example, assuming the PREP Act declaration is read to cover this situation, the liability protections must still
accord with the statute. To be a covered countermeasure under the PREP Act, the vaccine must be approved, licensed,
or authorized for emergency use by FDA. 42 U.S.C. §247d-6d(i)(1)(C), (7)(B). Comirnaty and the Pfizer-BioNTech
vaccine are licensed and authorized for emergency use by FDA, respectively, and are thus covered countermeasures.
Read literally, the PREP Act’s definition of covered countermeasure requires only that “the biological product … is
authorized” (or licensed) and does not speak to the authorization of particular uses. 42 U.S.C. §247d-6d(i)(1)(C),
(7)(B)(i). That said, a court might understand the word authorized (or licensed) to imply that the actual use at issue
must be within the scope of the EUA (or approved biologics license) in order to be a “covered countermeasure.”
88 CDC, “COVID-19 Vaccine FAQs for Healthcare Professionals” (see section “Off-Label Use”).
89 See CRS Legal Sidebar LSB10573, COVID-19 Vaccination Requirements: Potential Constraints on Employer
Mandates Under Federal Law, by April J. Anderson and Victoria L. Killion; see also Equal Employment Opportunity
Commission, “What You Should Know About COVID-19 and the ADA, the Rehabilitation Act, and Other EEO
Laws,” accessed September 9, 2021, https://www.eeoc.gov/wysk/what-you-should-know-about-covid-19-and-ada-
rehabilitation-act-and-other-eeo-laws (“The federal [employment laws] do not prevent an employer from requiring all
employees physically entering the workplace to be vaccinated for COVID-19, subject to the reasonable accommodation
provisions of Title VII [relating to religious objections] and the ADA [relating to disabilities].”).
90 Jacobson v. Massachusetts, 197 U.S. 11, 26–31 (1905); Zucht v. King, 260 U.S. 174, 176 (1922) (“[Jacobson] settled
that it is within the police power of a State to provide for compulsory vaccination.”).
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appropriate exemptions).91 Based on this precedent, legal challenges to public schools’ and
employers’ COVID-19 vaccine mandates have largely been rejected by courts in early stages of
litigation.92
Prior to FDA approval of the Pfizer-BioNTech COVID-19 vaccine, some commentators argued
that the mandates for EUA-authorized vaccines may not be legal under the EUA statute.93 In
particular, Section 564(e)(1)(A)(ii)(III) of the PHS Act requires the Secretary of HHS to ensure
that individuals receiving EUA products “are informed … of the option to accept or refuse
administration of the product, of the consequences, if any, of refusing administration of the
product, and of the alternatives to the product that are available and of their benefits and risks.”94
In these commentators’ view, this language might suggest that mandating EUA products is
“categorically prohibited” because the recipient must have the “option to accept or refuse
administration of the product.”95 Others read this provision not to prohibit schools’ or employers’
vaccine requirements but merely to require that vaccine recipients receive appropriate
information—such as the FDA fact sheets for COVID-19 vaccines.96
In a recent opinion, the Office of Legal Counsel (OLC)—the division of the Department of
Justice that provides legal advice to the President—considered and rejected the argument that
Section 564(e)(1)(A)(ii)(III) prohibits vaccine mandates.97 In OLC’s view, this section “concerns
only the provision of information to potential vaccine recipients and does not prohibit public or
private entities from imposing vaccination requirements.”98 Consistent with this view, one district
court summarily rejected this statutory argument in a challenge to a private hospital’s requirement
that its employees receive COVID-19 vaccines prior to full FDA approval.99

91 See CRS Report R46745, State and Federal Authority to Mandate COVID-19 Vaccination, by Wen W. Shen, pp. 3-4
(collecting cases). Presuming that it acts pursuant to valid statutory and constitutional authority, Jacobson implies that
the federal government has power to require vaccination in some circumstances—for example, for federal employees.
See Executive Order on Requiring Coronavirus Disease 2019 Vaccination for Federal Employees, September 9, 2021,
https://www.whitehouse.gov/briefing-room/presidential-actions/2021/09/09/executive-order-on-requiring-coronavirus-
disease-2019-vaccination-for-federal-employees/; see generally CRS Legal Sidebar LSB10633, Federal Employees and
COVID-19 Vaccination Attestations: Immediate Takeaways, by April J. Anderson, Wen W. Shen, and Jon O.
Shimabukuro.
92 See, for example, Klaassen v. Trustees of Indiana Univ., No. 1:21-CV-238 DRL, 2021 WL 3073926 (N.D. Ind. July
18, 2021) (denying preliminary injunction against Indiana University’s COVID-19 vaccine mandate for students),
motion for injunction pending appeal denied, 7 F.4th 592, 593 (7th Cir. 2021) (“Given [Jacobson], there can’t be a
constitutional problem with [requiring] vaccination against SARS-CoV-2.”); Bridges v. Houston Methodist Hosp., No.
CV H-21-1774, 2021 WL 2399994, at *1 (S.D. Tex. June 12, 2021) (dismissing wrongful termination claim based on
private-employer COVID-19 vaccine mandate); Harris v. Univ. of Massachusetts, No. 21-CV-11244-DJC, 2021 WL
3848012, at *1 (D. Mass. Aug. 27, 2021) (denying preliminary injunction against University of Massachusetts’
COVID-19 vaccine mandate for students); Norris v. Stanley, No. 1:21-CV-756, 2021 WL 3891615, at *1 (W.D. Mich.
Aug. 31, 2021) (denying temporary restraining order against COVID-19 vaccine mandate for Michigan State
University employees).
93 Efthimios Parasidis and Aaron S. Kesselheim, “Assessing the Legality of Mandates for Vaccines Authorized Via an
Emergency Use Authorization,” https://www.healthaffairs.org/do/10.1377/hblog20210212.410237/full/.
94 21 U.S.C. §360bbb-3(e)(1)(A)(ii)(III).
95 Parasidis and Kesselheim, footnote 93.
96 Anderson, Shen, and Shimabukuro, footnote 91, at 6 (explaining this argument).
97 OLC, “Whether Section 564 of the Food, Drug, and Cosmetic Act Prohibits Entities from Requiring the Use of a
Vaccine Subject to an Emergency Use Authorization,” July 6, 2021, https://www.justice.gov/olc/file/1415446/
download (hereinafter OLC Section 564 Opinion).
98 OLC Section 564 Opinion, p. 7.
99 Bridges v. Houston Methodist Hosp., No. CV H-21-1774, 2021 WL 2399994, at p. *2 (S.D. Tex. June 12, 2021).
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It is therefore not clear that the EUA status of a vaccine has any bearing on the authority of
schools and employers to mandate that vaccine. Now that FDA has approved Comirnaty, legal
arguments against vaccine mandates that relied on COVID-19 vaccines’ EUA status are now
largely moot.100 To that extent, FDA’s approval of Comirnaty may reduce any legal uncertainty
surrounding vaccine mandates.
For the most part, however, the legal authority for COVID-19 vaccine mandates—and the
statutory or constitutional constraints on them—are the same before and after Comirnaty’s
licensure.101 As a practical matter, to the extent that some employers and schools previously
refrained from vaccination mandates because no COVID-19 vaccine had been fully approved by
FDA, the approval of Comirnaty may result in greater use of vaccine mandates.102

Author Information

Kevin J. Hickey
Agata Bodie
Legislative Attorney
Analyst in Health Policy

Erin H. Ward

Legislative Attorney

100 At the time of this writing, Comirnaty is the only FDA-approved COVID-19 vaccine. The Moderna and Johnson &
Johnson COVID-19 vaccines are available only under an EUA. However, the argument against vaccine mandates based
on the EUA statute would appear to be precluded as long as the vaccine mandate at issue accepts an available FDA-
approved option (here, Comirnaty). See Norris v. Stanley, No. 1:21-CV-756, 2021 WL 3891615, at p. *2 (W.D. Mich.
Aug. 31, 2021) (“[S]hould Plaintiff be offered the FDA-approved Pfizer Comirnaty vaccine, her argument under the
EUA statute would be moot.…”). The legal issue may remain open with respect to vaccine mandates imposed on
individuals 12-15 years old, however, as no vaccine is approved for use in this age group. See “If Comirnaty is now
licensed, why did FDA reissue an EUA for the Pfizer-BioNTech vaccine?”
101 There are some exceptions, such as where particular statutory authorities (or, in the employment context, contractual
requirements such as collective bargaining agreements) distinguish between authorized and approved vaccines. For
example, the Department of Defense interprets Title 10, Section 1107a, of the U.S. Code to preclude a mandate for
EUA vaccines unless the President issues a waiver. See OLC Section 564 Opinion, pp. 16-17.
102 See, for example, Deepa Shivaram, “Why Pfizer’s FDA Approval Matters and What It Means for Vaccine
Mandates,” NPR, August 24, 2021, https://www.npr.org/sections/coronavirus-live-updates/2021/08/24/1030267314/
pfizer-vaccine-covid-fda-approval-kids-faq-mandate (“It’s likely we’ll see more vaccine requirements put in place now
that there is one vaccine with full FDA approval.”).
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