The NCBI Influenza Virus Resource is a specialized database that offers curated access to influenza virus sequence data, including types A, B, C and D. It allows researchers to search for nucleotide, protein sequences and NCBI Virus Assembly using a variety of filters, such as virus type, subtype (e.g., H1N1, H3N2), host species, geographic location, collection year, gene segment, etc.. Users can retrieve complete genomes or specific gene sequences, which are available for download in FASTA format.