X0306 4 2022-02-14 0 0001828522 eFFECTOR Therapeutics, Inc. EFTR 0001293973 Ehrlich Christopher B C/O EFFECTOR THERAPEUTICS, INC. 142 NORTH CEDROS AVENUE, SUITE B SOLANA BEACH CA 92075 1 0 0 0 Common Stock 2022-02-14 4 P 0 2000 4.45 A 15000 D Common Stock 2022-02-18 4 P 0 1000 4.30 A 16000 D Common Stock 142168 I By Locust Walk Partners LLC Common Stock 1034 I By Locust Walk Partners LLC The price reported in Column 4 is a weighted average price. These shares were purchased in two transactions at prices ranging from $4.40 to $4.50. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote. Represents shares held directly by the Sponsor, of which Locust Walk Partners LLC ("LWP") is a member. LWP has allocated these shares to the reporting person. Represents shares held directly by the Sponsor, of which LWP is a member. LWP has allocated these shares to the reporting person's spouse. /s/ Michael Byrnes, Attorney-in-Fact for Christopher B. Ehrlich 2022-02-22