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United States securities and exchange commission logo





                            November 26, 2021

       Andreas Typaldos
       Chief Executive Officer
       Petra Acquisition, Inc.
       5 West 21st Street
       New York, NY 10010

                                                        Re: Petra Acquisition
Inc.
                                                            Amendment No. 1 to
Registration Statement on Form S-4
                                                            Filed November 4,
2021
                                                            File No. 333-259638

       Dear Mr. Typaldos:

             We have reviewed your amended registration statement and have the
following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by amending your registration
statement and providing the
       requested information. If you do not believe our comments apply to your
facts and
       circumstances or do not believe an amendment is appropriate, please tell
us why in your
       response.

              After reviewing any amendment to your registration statement and
the information you
       provide in response to these comments, we may have additional comments.
Unless we note
       otherwise, our references to prior comments are to comments in our
October 25, 2021 letter.

       Amendment No. 1 to Registration Statement on Form S-4

       Cover Page

   1.                                                   We note your response
to prior comment 1. Please revise your cover page to disclose the
                                                        ownership percentages
of the Sponsor and Insiders, the Public Stockholders and the
                                                        existing holders of
Revelation's stock in the combined company.
 Andreas Typaldos
FirstName LastNameAndreas Typaldos
Petra Acquisition, Inc.
Comapany 26,
November  NamePetra
               2021 Acquisition, Inc.
November
Page  2   26, 2021 Page 2
FirstName LastName
Q. Did the Board obtain a third-party valuation or fairness opinion in
determining whether or not
to proceed with the Business Combination?, page 8

2.       Please revise to address the following:
             Clarify that the Petra Board approved the business combination
agreement prior to
             receipt of the fairness opinion.
             Quantify the deferred underwriting, Business Combination, and
other fees payable to
             LifeSci Capital upon merger consummation.
             Disclose LifeSci   s ownership stake in Revelation.

         In addition, add a separate Question and Answer immediately following
the existing one
         to highlight and explain that LifeSci negotiated the terms of the
business combination
         agreement on behalf of Petra notwithstanding interests different from
or in addition
         to those held by other Petra stockholders. With reference to the
disclosure on page 107,
         the Q&A should explain that LifeSci negotiated with Revelation
concerning the amount of
         LifeSci   s deferred underwriting fee at the same time that LifeSci
and Revelation were
         negotiating Revelation   s valuation for purposes of determining how
much equity would be
         allocated to the parties in the business combination.
Summary of the Proxy Statement/Prospectus
Petra's Reasons for the Business Combination, page 21

3.       We note your response to prior comment 10 and re-issue. The risks
described beginning
         on page 22 are primarily risks related to the business combination
process and COVID-19
         and are not risks or uncertainties that are specific to Revelation and
its business. Based on
         your response letter and in particular your statement that the risks
related to Revelation
         that Petra's board of directors considered are set forth beginning on
page 22 of the
         document, it appears that Petra's board of directors did not consider
risks unique to
         Revelation and its business in making its decision to approve the
Business Combination.
         Accordingly, please revise your disclosure here and on page 110 to
clarify, if true, that
         Petra's board of directors did not evaluate risks that were specific
and unique to
         Revelation in making its decision to approve the Business Combination.

         Please also revise your disclosure here and on page 110 to disclose
the material risks to
         unaffiliated investors presented by taking the company public through
a merger rather
         than an underwritten offering.
4.       We note your statements here and pages 109 and 152 indicating that
data from REVDx-
         501 correlate well with PCR for SARS-CoV-2. Please revise to reflect
your disclosure on
         page 169 which indicates that REVDx-501 returned numerous positive
tests from test
         samples that were PCR negative.
 Andreas Typaldos
FirstName LastNameAndreas Typaldos
Petra Acquisition, Inc.
Comapany 26,
November  NamePetra
               2021 Acquisition, Inc.
November
Page  3   26, 2021 Page 3
FirstName LastName
Revelation's Reasons for the Business Combination, page 23

5.       We note your response to prior comment 7. Please revise your
disclosure in this section to
         clarify, if true, that the pro forma enterprise value of approximately
$128M considered by
         Revelation excluded pro forma cash, including any funds from the trust
account.
6.       Please revise here and in the Background of the Business Combination
section to explain
         why Revelation discontinued its pursuit of the initial public offering
in favor of a business
         combination with a SPAC entity, particularly given your disclosures
that Revelation
         received preliminary indications of interest from new institutional
investors at valuations
         ranging from $120 million to $150 million. Also, revise to clarify
what type of initial
         public offering was pursued (e.g., firm commitment, best efforts,
etc.).
Risk Factors
The Proposed Charter provides..., page 69

7.       Please revise this risk factor to reflect your disclosure elsewhere in
the proxy
         statement/prospectus that your Delaware exclusive forum provision will
not apply to suits
         brought to enforce a duty or liability arising under the Exchange Act
or any other claim
         for which the federal courts have exclusive jurisdiction. Please also
revise to reflect your
         discussion elsewhere in the proxy statement/prospectus that Section 22
of the Securities
         Act creates concurrent jurisdiction for state and federal courts over
all actions brought to
         enforce any duty or liability created by the Securities Act or the
rules and regulations
         thereunder. Additionally, please revise to address any risks and
impact on investors, such
         as increased costs to bring a claim and that that these provisions can
discourage claims or
         limit inventors' ability to bring a claim in a judicial forum that
they find favorable.
Unaudited Pro Forma Combined Condensed Financial Inormation
Unaudited Pro Forma Combined Condensed Balance Sheet, page 94

8.       Please revise the adjustments in Notes (C) and (D) in the unaudited
pro forma combined
         balance sheet since the adjustments do not appear to be included in
the correct line based
         on the explanation in the Notes.
Background of the Business Combination, page 104

9.       With reference to the May 17 entry, please identify the Petra board
members who were
         informed of the potential conflicts of interest. With reference to
your disclosure on page
         110 indicating that Petra directors reviewed and considered LifeSci
s interests    during the
         negotiations," discuss how the Petra Board, or the informed board
members, reviewed
         these interests and what measures, if any, they considered to mitigate
the potential impacts
         that LifeSci   s conflicts could have on future negotiations. In
particular, specifically
         discuss whether the Board considered discontinuing LifeSci's
involvement in the merger
         negotiations.
 Andreas Typaldos
FirstName LastNameAndreas Typaldos
Petra Acquisition, Inc.
Comapany 26,
November  NamePetra
               2021 Acquisition, Inc.
November
Page  4   26, 2021 Page 4
FirstName LastName
Opinion of the Petra Financial Advisor, page 110

10.      We note your response to prior comment 22 and your statement that
Scalar did not rely on
         financial projections in connection with delivering its fairness
opinion. Please reconcile
         this response with your disclosure from page 111 which indicates the
following: "With
         respect to the financial projections referred to above and any other
forecasts or forward
         looking information, Scalar assumed, at the direction of the
management of Petra, that
         such projections, forecasts and information were reasonably prepared
and reflected the
         best then available estimates and good faith judgments of the matters
covered thereby."
         With reference to Annex D-1, also revise to identify the "internal
financial statements"
         reviewed by Scalar and, irrespective of reliance, revise to clarify
whether Scalar received
         financial projections prepared by either Petra or Revelation.
11.      We note that Scalar   s opinion indicates that the    Merger
Consideration is fair, from a
         financial point of view, to Petra as of September 17, 2021.    We also
note; however, that
         your disclosures on pages 146 and 241, and your Form S-1 IPO
prospectus disclosures,
         represent that a fairness opinion would address fairness viewed from
the standpoint of
         Petra   s    unaffiliated stockholders.    In light of these
disclosures, please tell us what
         consideration the Petra Board has given to the adequacy of Scalar   s
September 17 opinion
         for purposes of consummating the business combination.
Executive Officers and Directors of Revelation
Voting Agreements, page 194

12.      We note your response to prior comment 30. Please revise your
description of the AXA
         Voting Agreement in this section to clarify, if true, that the
agreement will terminate upon
         the consummation of the Business Combination, as indicated in your
response letter.
Certain Relationships and Related Person Transactions, page 239

13.      We note your response to prior comment 31 and re-issue. Please revise
this section to
         disclose the valuations accorded to Revelation in December 2020, May
2020 and January
         2021 when LifeSci made its investments.
 Andreas Typaldos
FirstName LastNameAndreas Typaldos
Petra Acquisition, Inc.
Comapany 26,
November  NamePetra
               2021 Acquisition, Inc.
November
Page  5   26, 2021 Page 5
FirstName LastName
       You may contact Jeanne Bennett at 202-551-3606 or Brian Cascio at
202-551-3676 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Alan Campbell at 202-551-4224 or Joe McCann at 202-551-6262 with any
other
questions.



                                                           Sincerely,

                                                           Division of
Corporation Finance
                                                           Office of Life
Sciences
cc:      Alex Weniger-Araujo
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