The FDA has approved Hiberix, a Haemophilus influenzae Type b (Hib) vaccine, as a booster dose for children 15 months through 4 years old. Hiberix is manufactured by GlaxoSmithKline, with U.S. headquarters in Research Triangle Park, N.C. and Philadelphia. A nationwide shortage of Hib vaccine began in December 2007 due to a voluntary recall by the manufacturer and subsequent production suspension of PedvaxHIB and COMVAX, two of four vaccines licensed in the United States for primary and booster immunization against invasive disease due to Hib. Both PedvaxHIB and COMVAX vaccines are manufactured by Merck & Co. Inc. (Whitehouse Station, N.J.). This shortage resulted in a recommendation by the U.S. Centers for Disease Control and Prevention to temporarily defer the Hib vaccine booster dose for children who were not at high risk for infection, until the vaccine supply could be restored. This deferral was in effect from Dec. 18, 2007, through June 25, 2009. Although current vaccine supply is sufficient to reinstate the booster dose and begin catch-up vaccination, it is not yet ample enough to support mass vaccination of all children whose boosters were deferred. “The FDA approved Hiberix under the agency’s accelerated approval pathway,” said Karen Midthun, M.D., acting director of the FDA’s Center for Biologics Evaluation and Research. “This approval will provide an additional safe and effective vaccine to help ensure that there is an adequate Hib vaccine supply during necessary catch-up vaccinations.” Before the availability of Hib vaccines, Hib disease was the leading cause of bacterial meningitis among children under 5 years old in the United States. Meningitis is an infection of the tissue covering the brain and spinal cord, which can lead to lasting brain damage and deafness. Hib disease can also cause pneumonia, severe swelling in the throat, infections of the blood, joints, bones, and tissue covering of the heart, as well as death. Hib disease is spread through the air by coughing and sneezing. In 1992, the FDA disseminated rules regarding accelerated approval. The rules allow for earlier approval of treatments that have been studied for their safety and effectiveness in treating serious or life-threatening illnesses and that provide meaningful therapeutic benefit to patients over existing treatments (including products that provide prophylaxis to those who would not otherwise be treated during a shortage). The use of such an approach can shorten the time required for product testing prior to receiving FDA approval. Accelerated approval is granted on the condition that clinical trials are continued during the post-approval marketing of the product to verify the anticipated clinical benefit. Hiberix is used in nearly 100 countries. The FDA based its conclusion that Hiberix is safe and effective for use as a booster dose in certain children in the United States on data from seven clinical studies conducted in Europe, Latin America and Canada that involved more than 1,000 children. As part of the approval, the manufacturer, GlaxoSmithKline, will conduct a post-market study in the United States to evaluate the safety and immunogenicity of primary and booster vaccination with Hiberix compared to a Hib vaccine already licensed in the United States. The study is intended to confirm the clinical benefit of booster immunization with Hiberix in accordance with the accelerated approval regulations, and to provide additional data on Hiberix for young infants. The most common side effects seen in the studies following a booster dose of Hiberix included pain and redness at the injection site, fever, fussiness, loss of appetite and restlessness.