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Influenza Phylogeny (Nextstrain)

Phylogeny of seasonal influenza — H3N2, H1N1pdm and type B. Evolution of haemagglutinin and predictions for vaccine strain selection.

Public source Source: Nextstrain Influenza · GISAID EpiFlu Updated: Weekly (Nextstrain server) influenzagenomicsphylogenyNextstrain

Nextstrain maintains continuously updated phylogenetic trees for seasonal influenza — a key tool for tracking antigenic drift and selecting strains for vaccines.

Available Nextstrain influenza builds

SubtypeSegmentWindowLink
H3N2HA (haemagglutinin)2 yearsnextstrain.org/flu/seasonal/h3n2/ha/2y
H3N2NA (neuraminidase)2 yearsnextstrain.org/flu/seasonal/h3n2/na/2y
H1N1pdmHA2 yearsnextstrain.org/flu/seasonal/h1n1pdm/ha/2y
Type B/VicHA2 yearsnextstrain.org/flu/seasonal/vic/ha/2y

What the tree shows

  • Antigenic clades — colour-coded groups sharing a similar antigen
  • Vaccine strains — the WHO-recommended strains for the season are marked
  • Geographic distribution — where each sequence comes from
  • HA mutations — amino-acid substitutions mapped onto the tree
Open Nextstrain — H3N2 HA (2 years)

Nextstrain Influenza · Bedford Lab · sequences from GISAID EpiFlu

Processing of personal data

What we collect

Web server access log — IP address, time, page address, browser type and referring page. Deleted after 14 days.

Visit counts by organisation — the IP address is resolved to an organisation (for example “Charles University”) and discarded. Only counts are kept. They are not personal data.

Which pages are read — our own analytics running on our server, with no cookies and no device identifier. The data does not go to third parties.

On your device we store a single item, and only so that this notice does not appear on every visit. It is not an identifier and it goes nowhere.

Your rights

You have the right of access to your data, to rectification or erasure, to restriction of processing, to object, and to lodge a complaint with the Czech Data Protection Authority.

⚠️ In practice: we cannot find you in the access log unless you tell us the IP address and roughly when you visited — we keep nothing else to search on.

The controller is the Institute of Molecular Genetics of the Czech Academy of Sciences. Contact: hpaces@img.cas.cz