Pharmaceutical giant Merck & Co. is voluntarily recalling its hepatitis B vaccine because the glass vials are cracked, federal health officials announced Friday.
Officials at the U.S. Food and Drug Administration said the recall was initiated out of an abundance of caution because of a possibility of bacterial contamination.
Doctors, pharmacists and hospitals are being asked to quarantine affected vials of Recombivax hepatitis B vaccine from lot J001183.
The recall affects only the single lot of Recombivax, a formulation developed to prevent hepatitis B in adults. Merck makes a separate hepatitis B vaccine for children.
More than 27,000 vials, which were shipped nationwide, are involved in the recall. All were distributed by Merck between March 12, 2013, and May 2, according to the FDA.
The company did not respond Friday to inquiries; FDA officials did not explain how the vials became cracked.
The federal agency said the company has conducted an investigation of the problem at its plant.
In a statement, FDA officials said Merck's investigation concluded that if a vial is cracked, neither the integrity of the container nor the sterility of the product can be assured.
As its name implies, Recombivax is made through recombinant DNA technology, which means a gene from the hepatitis B virus is spliced into yeast cells that multiply in a fermentation tank. A key viral surface protein is mass-produced during this process and used as the vaccine.
Minus the gene splicing, the process is vaguely similar to the production process of beer.
The vaccine must be refrigerated at about 36 degrees Fahrenheit to remain viable, company documents show.
Merck has manufactured Recombivax since 1986. The product is one of about half a dozen such vaccines on the market.
Hepatitis B is transmitted through contaminated blood products or body fluids and is a major cause of liver cancer. The recombinant vaccine is based on a viral surface protein, and therefore, cannot be a source of viral transmission.