X0306 4 2022-03-02 0 0001610950 Syneos Health, Inc. SYNH 0001766036 KEEFE MICHELLE C/O SYNEOS HEALTH, INC. 1030 SYNC STREET MORRISVILLE NC 27560 0 1 0 0 See remarks Class A Common Stock 2022-03-02 4 A 0 7845 0.00 A 54156 D Class A Common Stock 2022-03-02 4 A 0 1997 0.00 A 56153 D Class A Common Stock 2022-03-02 4 A 0 2158 0.00 A 58311 D Class A Common Stock 2022-03-02 4 F 0 5289 80.75 D 53022 D Represents performance restricted stock units that were earned based upon performance criteria for the year ended December 31, 2021. Includes 84 shares acquired under the Issuer's Employee Stock Purchase Plan on February 28, 2022. Represents performance restricted stock units that were earned based upon performance criteria for the year ended December 31, 2021 and will vest in full once the Compensation and Management Development Committee (the "Committee") of the Board of Directors of Syneos Health, Inc. (the "Issuer") determines the attainment level of the performance goals for the year ended December 31, 2022, subject to continued employment. Represents performance restricted stock units that were earned based upon performance criteria for the year ended December 31, 2021 and will vest in full once the Committee determines the attainment level of the performance goals for the year ended December 31, 2023, subject to continued employment. President, Medical Affairs & Commercial Solutions /s/ Sara Epstein, Attorney-in-Fact 2022-03-04