Fig. 1

Phylogenetic inference of the old smallpox vaccines VK01, VK02, VK05, VK08, and VK12. The multi-alignment of 37 orthopoxvirus genomes, including the VK samples, was used as input for tree construction by using MEGA 6, opting for the maximum likelihood method based on the Tamura-Nei substitution model, Uniform rates model with 1000 bootstrap replicates. Numbers indicate the percentage of bootstrap support from 1000 replicates (> 50% is shown). The scale bar indicates the number of substitutions per site. The VACV clusters are indicated on the right. A similar tree topology was obtained by using the neighbor-joining method. GenBank accession numbers are indicated in the “Availability of data and materials” section