Charred bits of plastic shrink wrap have been found in vials of Merck & Co. (MRK) vaccines, the latest quality problem identified by U.S. regulators at the company’s biggest vaccine-making plant and an issue the drug maker said it is still working to resolve. Merck said it isn’t aware of any adverse health events associated with the problem, and that it is confident in the safety and efficacy of its products. The affected vaccines included Gardasil for the prevention of HPV infection, Varivax for chicken pox, Pneumovax for pneumococcal disease, Zostavax for shingles and MMR II for measles, mumps and rubella.
