X0306 4 2021-09-01 0 0001029142 DYNAVAX TECHNOLOGIES CORP DVAX 0001580849 Janssen Robert C/O DYNAVAX TECHNOLOGIES 2100 POWELL STREET, SUITE 900 EMERYVILLE CA 94608 0 1 0 0 Senior Vice President Common Stock 2021-09-01 4 M 0 900 10.47 A 9176 D Common Stock 2021-09-01 4 S 0 900 20.15 D 8276 D Stock Option (Right to Buy) 10.47 2021-09-01 4 M 0 900 D 2026-02-21 Common Stock 900 103100 D The sales reported on this Form 4 were effected pursuant to a 10b5-1 trading plan adopted on August 11, 2020. This transaction was executed in multiple trades at prices ranging from $20.03 to $20.25; the price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide full information regarding the number of shares and prices at which the transactions were effected upon request to the SEC staff, Dynavax, or a security holder of Dynavax. This option grant will vest over three (3) years with one-third (1/3) of the shares subject to the option vesting twelve months after the grant date, and one thirty-sixth (1/36) of the shares subject to the option vesting on the last day of each month thereafter. Not applicable. /s/ Robert Janssen 2021-09-03