"The intent in our research was to use the latest technologies to show that live vaccines only contained the expected viral genomes and no other," said Eric Delwart of the Blood Systems Research Institute, the study's lead author. He said the scientists were "quite surprised" to find the benign pig virus in a vaccine use to prevent diarrhea in babies.
Delwart said he discovered the virus in January using a deep DNA sequencing technology and then contacted biologists Crystal Jaing and Shea Gardner, along with computer scientist Kevin McLoughlin, at the Lawrence Livermore National Laboratory to check his results.
The three Livermore researchers used a new detection technology, the Microbial Detection Array, to check the results. With 388,000 probes that fit on a one-inch wide, three-inch long glass slide, the array can detect or identify any of the approximately 60,000 viruses or 2,500 bacteria worldwide that have been sequenced.
The Livermore researchers confirmed the presence of the pig virus DNA in the vaccine.
"One result of this research is that it demonstrates how modern technologies could change and drastically improve product safety," said Tom Slezak, Lawrence Livermore's scientific leader for Bioinformatics.
The study is detailed in the online Journal of Virology.