About
Nextstrain is an open-source project designed to unlock the scientific and public health potential of pathogen genome sequencing data. By reconstructing phylogenies from genomic mutations that accumulate during transmission, Nextstrain enables researchers to infer critical epidemiological patterns such as geographic spread, introduction timings, and epidemic growth rates — all in near real-time. The platform maintains continually updated analyses for a broad range of pathogens, including SARS-CoV-2, influenza (seasonal and H5N1), mpox, Ebola, tuberculosis, measles, RSV, HIV, Lassa, and many more. Each dataset is presented through interactive, browser-based visualizations that allow users to explore phylogenetic trees, clade assignments, geographic spread, and temporal dynamics. Nextclade, a companion tool integrated into the platform, provides in-browser phylogenetic placement, clade assignment, mutation calling, and sequence quality checks — without requiring any local software installation. Nextstrain Groups allows research labs and public health agencies to share their own datasets and narratives with the wider community. The platform also offers open-source bioinformatic workflows and analysis pipelines so that researchers can run their own analyses using the same robust infrastructure. Nextstrain is ideal for public health surveillance teams, academic researchers, infectious disease epidemiologists, and science communicators seeking an accessible yet powerful genomic epidemiology toolset.
Key Features
- Real-Time Phylogenetic Tracking: Continuously updated phylogenetic trees for 20+ pathogens including SARS-CoV-2, influenza, mpox, Ebola, and more, reflecting the latest available genome sequences.
- Interactive Data Visualizations: Browser-based interactive maps and phylogenies allow users to explore geographic spread, clade dynamics, mutation patterns, and temporal evolution of pathogens.
- Nextclade In-Browser Analysis: Upload sequences directly in the browser for instant phylogenetic placement, clade assignment, mutation calling, and sequence quality assessment — no installation required.
- Nextstrain Groups for Data Sharing: Research labs, public health agencies, and other organizations can publish and share their own datasets and narratives through the Nextstrain Groups feature.
- Open-Source Bioinformatic Workflows: Full suite of open-source pipelines and analysis tools enabling researchers to run reproducible genomic epidemiology analyses using the same infrastructure as core Nextstrain datasets.
Use Cases
- Public health agencies monitoring the real-time spread and evolution of SARS-CoV-2 variants to inform vaccine and policy decisions.
- Epidemiologists tracking the geographic introduction and transmission chains of outbreak pathogens such as Ebola or mpox.
- Researchers studying antigenic drift in seasonal influenza to guide annual vaccine strain selection.
- Academic institutions teaching phylogenetics, genomic epidemiology, and bioinformatics using real-world pathogen data.
- Biosurveillance teams analyzing novel pathogen outbreaks, such as H5N1 cattle or Oropouche virus, to assess global spread risk.
Pros
- Completely Free and Open Source: Nextstrain and all its tooling are freely available under open-source licenses, making powerful genomic epidemiology accessible to institutions of any size.
- Broad Pathogen Coverage: Tracks over 20 pathogens in near real-time, providing a one-stop resource for global infectious disease surveillance across a wide range of viruses and bacteria.
- No Installation Required for Core Features: Nextclade and most visualizations run entirely in the browser, removing technical barriers for epidemiologists and public health officials who need quick insights.
- Supports Community Data Sharing: Nextstrain Groups enables research labs and public health entities to publish their own analyses within the same trusted platform, fostering collaborative science.
Cons
- Steep Learning Curve for Advanced Use: Running custom bioinformatic workflows or contributing new datasets requires significant expertise in genomics, bioinformatics, and command-line tools.
- Narrow Domain Focus: The platform is purpose-built for pathogen genomic epidemiology, making it highly specialized and not applicable to general data analysis or non-infectious-disease research.
- Dependent on Available Genome Sequences: The quality and timeliness of analyses depend entirely on the volume and quality of publicly shared genomic sequences, which varies by pathogen and region.
Frequently Asked Questions
What is Nextstrain?
Nextstrain is an open-source platform for real-time genomic epidemiology. It reconstructs pathogen phylogenies from genome sequence data and presents findings through interactive visualizations to support public health surveillance and scientific research.
Is Nextstrain free to use?
Yes. Nextstrain is entirely free and open source. All core analyses, visualizations, and tooling — including Nextclade — are available at no cost to researchers, public health professionals, and the general public.
Which pathogens does Nextstrain track?
Nextstrain tracks over 20 pathogens in near real-time, including SARS-CoV-2, seasonal and avian influenza (H5N1), mpox, Ebola, tuberculosis, measles, RSV, HIV, Lassa, Nipah, norovirus, rabies, yellow fever, and more.
What is Nextclade and how does it differ from Nextstrain?
Nextclade is a companion tool integrated into the Nextstrain ecosystem. It allows users to upload their own pathogen genome sequences directly in the browser for phylogenetic placement, clade assignment, mutation calling, and sequence quality checks — without needing to install any software.
Can research labs share their own data on Nextstrain?
Yes. Through Nextstrain Groups, research laboratories, public health agencies, and other organizations can publish and share their own genomic datasets and narrative reports within the Nextstrain platform for the broader scientific community to access.
