Fig. 1

Filtration substantially enriches for virus reads. Plasma samples were spiked with three different viruses (adenovirus, HHV-4, poliovirus) and prepared under the three following conditions: same day comprised filtration, extraction, and freezing at −20 °C; pre-processed comprised filtration, freezing at −80 °C, and extraction; archived included freezing at −20 °C, filtration, and extraction. All conditions were tested with and without filtration. The experiment was performed in duplicates. a Distribution of sequencing reads into the taxonomic categories viral, human, bacterial, and unknown origin. b Number of reads obtained for each individual virus. c Fraction of all quality passing reads obtained for each individual virus