Frozen vaccine leads to call-backs

Ohio residents visiting an H1N1 clinic in Centerville also faced a potency problem, this one caused by product frozen in transit. More than 2,000 people vaccinated last week have received automated phone calls asking them to return for second shot. The county has scheduled another clinic for next week. 

During last week's clinic, nurses discovered that some vaccine located in the center of a 3,000-unit batch was frozen, according to a local press report. Officials therefore deemed all 3,000 units unacceptable.

Freezing is a vaccine potency-zapper. Officials made clear, however, that there were no safety issues. The shipment had clearly sustained temperatures below the acceptable range of 35 to 46 degrees Fahrenheit, though temperature indicators included with the shipment did not report it so.

Officials also made clear that the temperature transgression did not occur on their watch. "We have quality standards for maintaining, packing, and transporting vaccine to the delivery site. Since we followed all of our normal procedures and all of our systems were working properly, we believe the vaccine was frozen prior to being delivered to us," they write, in an online Q&A. Officials also mention that similar temperature transgressions have occurred elsewhere in the U.S.

The health officials fail to identify the maker of the frozen vaccine, but they note that clinic visitors aged six to 35 months need not return for another shot. The vaccine they received, as well as vaccine that was administered in nasal-mist form, were uncompromised. And clinic visitors who received a shot after 5:30 p.m. are also in the clear; by that time health care workers had discovered the frozen product and stopped using it, instead taking vaccine from an alternate source.

- here's the article