The European Medicines Agency (EMA) has opened a debate on the safe use of animal-derived products in vaccines. Publication of the draft guidelines comes three years after the discovery of pig-virus DNA in vaccines from GlaxoSmithKline ($GSK) and Merck ($MRK) prompted a regulatory rethink.
In April 2010 the use of new, more sensitive tests revealed the presence of contaminants in GSK and Merck rotavirus vaccines. The problem stemmed from the use of pig-derived products and, in the case of GSK, dated back to clinical testing of the vaccine. Since the contamination, EMA has worked to tighten quality controls and has now opened up draft guidelines for consultation.
The draft centers on the material behind the GSK and Merck contaminations, porcine trypsin. In the production of certain influenza and rotavirus vaccines, porcine trypsin is used to activate the virus. But, as it is derived from a pig's pancreas, its use creates the risk of contamination with any number of biological agents. This is what happened to GSK and Merck, and what EMA wants to keep from happening again.
EMA is advising vaccine manufacturers to mitigate risks through screening and processing. Quality control begins with the pancreatic glands, but EMA reports economic and organizational reasons make it seemingly impossible to test them individually. Once the glands are pooled, the risk of contamination in one spreading to the others increases. A combination of starting material tests and downstream virus inactivation is recommended to prevent contamination.
Failing to detect a contaminant could have significant consequences for vaccine manufacturers. EMA warns it could lead to shutdown of a production plant and pose a threat to patients. Viruses can alter the growth of cultured cells and therefore, theoretically, change vaccine properties.
- check out the EMA guidelines