Form 4 Filing for Altimmune, Inc.

This Form 4 filing details transactions by Arbet-Engels Christophe, Chief Medical Officer of Altimmune, Inc. On October 1, 2026, there were two primary transactions. First, 37,500 Restricted Stock Units (RSUs) were acquired, with each RSU representing a contingent right to one share of Common Stock. This acquisition had a transaction value of $0.00 per share. Second, 12,679 shares of Common Stock were disposed of at a price of $2.76 per share. These shares were surrendered to the Issuer solely to cover taxes associated with the vesting of RSUs. The RSUs vest over four years, with 25% vesting on October 1, 2026, and the remainder vesting annually over the next three years, contingent on continued service. Following these transactions, the reporting person holds 112,500 shares in RSUs and 24,821 shares of Common Stock.