2017-03-01. Comparison of Clade 6B.1 with A/California/07/2009 and A/Montana/04/2016
CA09: A/California/07/2009 like, current vaccine
MT16: A/Montana/04/2016 like, proposed by FutureFlu
HI Titers computed with the Antigenic Prediction Model:
Clade 6B.1 antigen against CA09 antiserum = 1,142
Clade 6B.1 antigen against MT16 antiserum = 2,616
Autologous titer = 2,560
Antigenic drifts between Clade 6B.1 and
● CA09 = |1 - log2 (1142) / log2 (2560)| = 1.03 AU
● MT16 = |1 - log2 (2616) / log2 (2560)| = 0.03 AU
With an antigenic distance greater than 1 Antigenic Unit, CA09 has drifted from the prevalent strains, while MT16 is highly aligned with Clade 6B.1 (= 0.03 AU). It is also evident in the phylogenetic tree of the clade (on left) including the vaccine candidates (shown in yellow).
Synonymous differences between the genomes of A/Michigan/45/2015 (MI15) and A/Montana/04/2016 (MT16)
Coordinate MI15 MT16 Coded
Codon Codon Amino Acid
047 AAC AAT N
131 GAG GAA E
177 CTT CTC L
313 CCG CCA P
317 GGA GGG G
337 GTT GTC V
526 ATT ATC I
554 TGC TGT C
2017-04-20. Antigenic Drift between A/Michigan/45/2015 and Clade 6B.2
2017-03-07. BLASTP Comparison of A/Michigan/45/2015 (recommended by WHO) and A/Montana/04/2016 (recommended by FutureFlu) showing 100% identiies
The computed antigenic distance is less that 0.25 Antigenic Units, which is within acceptable limit. N101S, V169T, N179S, V190I, T233I, E508G and D518E are the major mutational differences between the two Clades. Of these, N179S is significant because it eliminates a potential N-linked glycosylation site. The amino acid pattern of a potential site is NXS/T or NXXS/T. The mutation replaces the arginine with serine, thus disrupting the pattern.
Antigenic Drift between A/Michigan/45/2015 and representative members of Clade 6B.2
A/Brisbane/294/2016 | A/HongKong/90/2016 | A/Israel/Q-504/2015 | A/SouthAustralia/121/2016
> N101S N101S N101S N101S
> V169T V169T V169T V169T
> N179S N179S N179S N179S
> V190I V190I V190I V190I
> T233I T233I T233I T233I
A278S A278S A278S
> E508G E508G E508G E508G
> D518E D518E D518E D518E
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This website is currently tracking the H1N1pdm strain of the influenza virus. Extending the project to other three strains of the quadrivalent vaccine recommended by the World Health Organimzation, namely, H3N2, B/Victoria and B/Yamagata are works-in-progress.
2017-04-20: How does the efficacy of the A/Michigan/45/2015 vaccine strain compare with the emerging Clade 6B.2? More ...