United States securities and exchange commission logo January 7, 2021 Vipin K. Garg Chief Executive Officer Altimmune, Inc. 910 Clopper Road, Suite 201S Gaithersburg, Maryland Re: Altimmune, Inc. Registration Statement on Form S-3 Filed December 31, 2020 File No. 333-251858 Dear Dr. Garg: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Alan Campbell at 202-551-4224 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Joseph C. Theis, Esq.