Table 2. HA1 mutations present in strains with estimated growth rates.

HA1 amino acid mutations for each of the 12 strains with sufficient sequence counts to estimate growth rates. Mutations in known antigenic regions as defined by Muñoz and Deem, 2005, are in bold text, and mutations outside of antigenic regions are in regular weight text. The table lists all HA1 mutations relative to the most-recent common ancestor of the 12 strains.

Strain name	HA1 substitutions
A/TECPAN/017FLU/2023	E50K, F79V, I140K, I242M
A/Jeju/1047/2023	E50K, F79V, I140K
A/SENDAI/45/2023	E50K, F79V, T135A, I140K, S262N
A/Schleswig-Holstein/4/2023	R33Q, E50K, F79V, I140K, S262N
A/Busan/1301/2023	D53G, H156S, K276R
A/Finland/391/2023	D53G, D104G, I140K, H156S, K276R, R299K
A/Saint-Petersburg/RII-166/2023	E50K, D53N, N96S, I140K, H156S, Q173R, I192F, I223V, K276E
A/Massachusetts/18/2022	E50K, D53N, N96S, I140K, H156S, I192F, I223V
A/Georgia/40/2023	E50K, D53N, N96S, I140K, H156S, I192F, I223V, I242M
A/Bhutan/0845/2023	I25V, E50K, D53N, N96S, I140K, H156S, I192F, I223V
A/Ontario/RV00796/2023	E50K, D53N, N96S, N122D, I140K, H156S, I192F, I223V, K276E
A/Sydney/332/2023	E50K, D53N, N96S, N122D, I140K, H156S, I192F, I223V