Deep sequencing reveals viral vaccine contaminants

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Deep sequencing reveals viral vaccine contaminants

The sequence analysis revealed the expected vaccine strains in each preparation, and in three cases, other unexpected viral sequences. The retrovirus avian leukosis virus was found in the measles vaccine, but at a very low level (700 nucleotides from 4 sequence reads). A virus similar to simian retrovirus was identified in Rotateq (276 nucleotides from 1 sequence read). Significant levels of porcine cirovirus 1 were found in Rotarix. The entire viral genome sequence was deduced from 6344 sequence reads, comprising over 40% of the reads done for that vaccine.

The avian leukosis virus sequences found in the measles vaccine are in intact virions, as DNA treatment of the vaccines did not prevent their detection by polymerase chain reaction (PCR). However simian retrovirus DNA was not detected by PCR after DNAse treatment of Rotateq. Therefore the viral DNA detected in Rotateq vaccine most likely originates from host DNA present in the vaccine preparation. The cells used to produce Rotateq are Vero cells – African green monkey kidney cells. A defective form of simian retrovirus DNA, called proviral DNA, is integrated into Vero cell DNA....

http://www.forums.aboutmecfs.org/showthread.php?3753-Mouse-retrovirus-present-in-cell-lines-used-for-production-of-biologicals & p=66385 & posted=1#post66385