Manufacturers Sanofi Pasteur and GlaxoSmithKline are informing physicians about changes to the prescribing information of their seasonal influenza vaccines. The changes reflect concerns that the tip caps of flu vaccine products shipped in prefilled syringes may contain natural rubber latex, which can cause allergic reactions in latex-sensitive individuals.
GSK said in a letter to customers that the labeling changes, which were required by the FDA, will result in fewer doses of Fluarix being delivered to the U.S. market, while Sanofi Pasteur said in a letter to physicians that the alterations will result in a two- to three-week delay in the company's shipments of Fluzone.
Novartis Vaccines and Diagnostics also has informed physicians that the tip caps of its flu vaccines -- Fluvirin and Agriflu -- shipped in prefilled syringes may contain natural rubber latex.
Sanofi Pasteur said in its letter that all injectable flu vaccine products that use syringe tip caps supplied by Helvoet Pharma are affected. Sanofi said the FDA informed the manufacturers of these products in mid-July that there was insufficient documentation to support "latex-free" claims made by Helvoet.
GSK emphasized in its letter to customers that the changes were not prompted by any reports of adverse events. However, in a separate letter to physicians, the manufacturer encouraged physicians to report suspected adverse events to the Vaccine Adverse Event Reporting System or to GSK by calling (888) 825-5249.
GSK also said in its customer letter that it "expects to invite" private customers, including group purchasing organizations, who buy vaccines on a 340B Drug Pricing Program contract and who placed their prebooked order reservations before Dec. 1, 2009, to confirm 100 percent of their doses.
However, private customers who purchase vaccines on the same type of contract but who placed their orders on or after Dec. 1 may only be invited to confirm a percentage of their prebooked reservation based on product availability, said the manufacturer.
It remains unclear how much GSK plans to cut its U.S. distribution of the vaccine, but GSK estimates that it will distribute more than 30 million doses of its flu vaccines -- Fluarix and Flulaval -- in the United States this season.
Flulaval, which is distributed only in multidose vials, is not affected by the label changes.
Sanofi Pasteur said in its letter to physicians that it still intends to distribute more than 70 million doses of Fluzone in the United States this season.