Vaccine Contamination: Pig Virus DNA Found in Rotarix

NVIC Vaccine News

Vaccine Contamination: Pig Virus DNA Found in Rotarix
by Barbara Loe Fisher

On March 22, 2010, Food and Drug Administration (FDA) officials adhering to the precautionary principle advised American doctors to suspend use of Rotarix vaccine until the agency finds out why DNA from a swine virus (porcine circovirus 1 or PCV1) was found in the live rotavirus vaccine. The FDA said there is "no evidence at this time" that the vaccine manufactured by GlaxoSmithKline and given to babies at 2,4 and 6 months of age to prevent diarrhea poses any safety risk.


Independent Lab Using New Technology Found Contamination

The discovery that viral DNA is contaminating Rotarix vaccine was made by a team of scientists at an independent research lab in San Fransisco, California, where they used new technology to detect fragments of viral genetic material in vaccines using genetic sequencing.

More testing confirmed that many copies of DNA from the pig virus were present in all Rotarix vaccine lots released since the vaccine was licensed in 2008 because the pig virus DNA also contaminated the working cell bank and the original viral "seed" stock, from which Rotarix vaccine was first produced.


Two Other Live Virus Vaccines Contaminated

The surprising discovery reportedly was made after the independent lab used new technology to evaluate the purity of eight live virus vaccines for polio, rubella, measles, yellow fever, human herpes 3 (varicella or chicken pox), rotavirus (Rotarix and RotaTeq) and MMR. In addition to pig viral DNA found in Rotarix vaccine, low levels of DNA fragments from avian (bird) leukosis virus (a retrovirus) was found in measles vaccine and DNA fragments of a virus similar to simian (monkey) retrovirus was found in RotaTeq vaccine.


FDA Looking For Answers

After the team double checked their findings, researchers notified GlaxoSmithKline (GSK) on February 9, 2010 and GSK notified the FDA on March 15, 2010, which prompted the FDA's action on March 22, 2010 to suspend use of Rotarix. The FDA says it "does not know how DNA from PCV1 came to be present in Rotarix" or whether "this means that intact virus is present. Additional studies are being conducted."


Rotavirus Vaccines Use Monkey, Cow, Pig Materials for Production

Rotarix is a genetically engineered vaccine that GSK created by isolating human rotavirus strain infecting a child in Cincinnati and using African Green monkey kidney cells to produce the original viral seed stock from which all Rotarix vaccine has been made. In the FDA licensing process, Rotarix had to meet certain FDA standards, that included demonstrating the vaccine was not contaminated with, for example TSE (Transmissable Spongiform Encephalopathy or "mad cow" disease, a brain wasting disease) or with cow viruses because bovine (cow) serum was used to prepare the original viral seed stock. Porcine trypsin, an enzyme in the pancreatic juice of a pig, was also used to make the viral seed stock.

RotaTeq is a genetically engineered vaccine containing five human-cow reassortment strains of rotavirus that were created at the Children's Hospital of Pennsylvania (CHOP), where strains of rotavirus that give cows diarrhea were combined with strains of rotavirus that cause diarrhea in humans. The reassortment viruses were transported to Merck, where master seeds were produced using African Green Monkey kidney cell cultures. Fetal bovine (cow) serum and porcine trypsin was used to make the "seed" stock. There are small amounts of bovine serum and cell culture media (monkey viral DNA) that remain in RotaTeq vaccine.... click here to read the entire commentary and watch a video.


NVIC's updated Rotavirus and Rotavirus Vaccines information with references on www.NVIC.org.