X0407 4 2023-04-03 0 0001786255 Icosavax, Inc. ICVX 0001874371 Holtzman Douglas C/O ICOSAVAX, INC. 1930 BOREN AVE., SUITE 1000 SEATTLE WA 98101 0 1 0 0 Chief Scientific Officer 1 Common Stock 2023-04-03 4 M 0 20443 1.04 A 310497 D Common Stock 2023-04-03 4 S 0 20143 6.0785 D 290354 D Common Stock 2023-04-03 4 S 0 300 6.56 D 290054 D Common Stock 2792 I By Stanley Holtzman Stock Option (Right to Buy) 1.04 2023-04-03 4 M 0 20443 0.00 D 2031-01-28 Common Stock 20443 44977 D The sales reported herein were made pursuant to a Rule 10b5-1 Trading Plan adopted by the Reporting Person on December 2, 2022. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.55 to $6.52. 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 sold at each separate price within the range set forth in this footnote. Douglas Holtzman, Ph.D. holds power-of-attorney (POA) over the shares owned by Stanley Holtzman. As POA, Dr. Holtzman holds voting and dispositive control over such shares. Dr. Holtzman disclaims beneficial ownership of the shares over which he has POA except to the extent of any pecuniary interest therein. 25% of the shares subject to the option vested on 1/14/2022, and 1/48th of the shares subject to the option vest monthly thereafter. /s/ Elizabeth Bekiroglu, Attorney-in-Fact 2023-04-05