Experimental RNA Therapy Shows Promise Against Ebola Virus in Monkey Studies

Abstract

tionally, fragments of simian retrovirus DNA with an inactivating mutation were found in RotaTeq and also in the Vero cells (a cell line from the kidney cells from an African green monkey) from which the vaccines are derived. Delwart explained that the use of cells from other species in the production of vaccine can lead to leakage of cellular DNA and the introduction of noninfectious proviral DNA in vaccines. A possible culprit for introducing PCV1 into Rotarix may have been porcine pancreas-derived trypsin. He said that while the PCV1 contamination they found is undesirable, in some ways it is a best-case scenario because the virus has been well studied and appears to be noninfectious to humans. The discovery of unexpected viral DNA in the vaccine should not necessarily be cause for alarm, Delwart added. “We are constantly bombarded with viruses, particularly in the digestive tract [from meat, plants, and insects],” Delwart said. “We are finding them because the technology has changed.” In the future, use of these technologies early in the vaccine production process should allow them to be removed quickly, he added. Until the makers of the rotavirus vaccines are able to develop new versions of their vaccines, the FDA is requiring that the labels of Rotarix and RotaTeq be updated to disclose the presence of the PCV viruses. And Stapleton recommends that physicians inform parents that the viral DNA poses a theoretical risk, though extensive investigation has turned up no evidence of harm. Some parents may choose to decline the vaccine on this basis, he noted. “You have to be transparent and tell parents about the finding but [also inform them] that the vaccines are still recommended,” Stapleton said.