X0306 4 2023-01-20 0 0001828522 eFFECTOR Therapeutics, Inc. EFTR 0001559583 Smither John W C/O EFFECTOR THERAPEUTICS, INC. 142 NORTH CEDROS AVENUE, SUITE B SOLANA BEACH CA 92075 1 0 0 0 Stock Option (Right to Buy) 0.4688 2023-01-20 4 A 0 36875 0.00 A 2033-01-19 Common Stock 36875 36875 D The shares subject to the option will vest in substantially equal monthly installments over 12 months, commencing on January 20, 2023, subject to the Reporting Person's continued service with the Issuer through each vesting date. /s/ Michael Byrnes, Attorney-in-Fact for John W. Smither 2023-01-24