About

This repository analyzes viral genomes using Nextstrain to understand how SARS-CoV-2, the virus that is responsible for the COVID-19 pandemic, evolves and spreads.

We maintain a number of publicly-available builds, visible at nextstrain.org/ncov.

See our change log for details about backwards-incompatible or breaking changes to the workflow.

Resources

Use Nextstrain to analyze your SARS-CoV-2 data

We've written a comprehensive guide to get you up and running in <1 hr. Click on the below links to follow it. It covers:

Introduction (Start here)
Setup and installation
Preparing your data
Orientation: analysis workflow
Orientation: which files should I touch?
Running & troubleshooting
Customizing your analysis (see also: reference for all configuration parameters)
Customizing your visualization
Options for visualizing and sharing results (including working with sensitive metadata)
Interpreting your results
Writing a narrative to highlight key findings
Running the pipeline starting with multiple inputs

Reference guides

Download formatted datasets

The hCoV-19 / SARS-CoV-2 genomes were generously shared via GISAID. We gratefully acknowledge the Authors, Originating and Submitting laboratories of the genetic sequence and metadata made available through GISAID on which this research is based.

In order to download the GISAID data to run the analysis yourself, please see this guide.

Please note that data/metadata.tsv is no longer included as part of this repo. However, we provide continually-updated, pre-formatted metadata & fasta files for download through GISAID.

Read previous Situation Reports

We issued weekly Situation Reports for the first ~5 months of the pandemic. You can find the Reports and their translations here.

FAQs

Can't find your sequences in Nextstrain? Check here for common reasons why your sequences may not be appearing. You can also use clades.nextstrain.org to perform some basic quality control on your sequences. If they are flagged by this tool, they will likely be excluded by our pipeline.
For information about how clades are defined, and the currently named clades, please see here. To assign clades to your own sequences, you can use our clade assignment tool at clades.nextstrain.org.

Bioinformatics notes

Site numbering and genome structure uses Wuhan-Hu-1/2019 as reference. The phylogeny is rooted relative to early samples from Wuhan. Temporal resolution assumes a nucleotide substitution rate of 8 × 10^-4 subs per site per year. There were SNPs present in the nCoV samples in the first and last few bases of the alignment that were masked as likely sequencing artifacts.