# H1N1 pdm09 tree - EPI ISL identifiers

**URL:** <https://nextstrain.discourse.group/t/h1n1-pdm09-tree-epi-isl-identifiers/1921>\
**Category:** General\
**Created:** [June 26, 2025, 8:16am UTC](https://nextstrain.discourse.group/t/h1n1-pdm09-tree-epi-isl-identifiers/1921 "2025-06-26T08:16:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![georges.hanna](https://yyz1.discourse-cdn.com/flex031/user_avatar/nextstrain.discourse.group/georges.hanna/32/695_2.png) [@georges.hanna](https://nextstrain.discourse.group/u/georges.hanna)\
**Post date:** [June 26, 2025, 8:16am UTC](https://nextstrain.discourse.group/t/h1n1-pdm09-tree-epi-isl-identifiers/1921/1 "2025-06-26T08:16:47Z")

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I’m trying to download the acknowledgments for the H1N1pdm09 (seasonal influenza) dataset from Nextstrain. However, I can only see the virus names — the EPI\_ISL identifiers for the sequences are not available. I need to retrieve the actual sequences used to generate the phylogenetic tree. Do you have any suggestions on how to access them?

Thank you !

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**Author:** ![jlhudd](https://yyz1.discourse-cdn.com/flex031/user_avatar/nextstrain.discourse.group/jlhudd/32/583_2.png) [@jlhudd](https://nextstrain.discourse.group/u/jlhudd)\
**Post date:** [June 26, 2025, 11:04pm UTC](https://nextstrain.discourse.group/t/h1n1-pdm09-tree-epi-isl-identifiers/1921/2 "2025-06-26T23:04:45Z")

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Welcome, @georges.hanna! This is [an open issue with our seasonal flu analyses](https://github.com/nextstrain/seasonal-flu/issues/178) that depends on a larger change to our data backend. We hope to have this resolved in the next month or so. If you have a GitHub account, you can comment on that issue and/or get notifications for that issue which will automatically alert you when we’ve resolved it.

I’m sorry we don’t have a better fix in the short term, though.