Vaccine Shortage Dictates Deferring Hib Booster in Healthy Kids

For a typical family medicine practice, administering immunizations is part and parcel of the everyday routine -- especially when it comes to youngsters who've come in for their well-child visits. So, deciding to forgo a key piece of the recommended childhood immunization schedule may seem counterintuitive. In the face of an ongoing shortage of Haemophilus influenzae type b, or Hib, conjugate vaccine, however, the CDC is reminding vaccine providers about an interim recommendation that urges temporary deferral of the Hib vaccine booster usually given to healthy children at the 12- or 15-month visit except for certain high-risk children.

In a communication sent last month to the AAFP and the American Academy of Pediatrics, or AAP, Gregory Wallace, M.D., M.P.H., chief of the Vaccine Supply and Assurance Branch in the Immunization Services Division of the CDC's National Center for Immunization and Respiratory Diseases, said the agency had received anecdotal reports that some vaccine providers are continuing to administer the Hib vaccine booster dose to all comers, despite a CDC recommendation to the contrary. CDC officials are concerned, he said, that providers may not be aware of the interim recommendation and the guidance it provides during the current shortage of Hib vaccine.

The shortage grew out of a voluntary recall Merck & Co. Inc. announced last December because of concerns about potential product contamination. The recall involved two of Merck's Hib-containing vaccine products -- its monovalent Hib conjugate vaccine, sold as PedvaxHIB, and its combination Hib/hepatitis B vaccine, COMVAX. In all, Merck recalled a dozen lots, or about 1 million doses, of vaccine.

Merck suspended production of the two vaccines at that time and projected that distribution of these products wouldn't resume until the fourth quarter of 2008.

Two Hib-containing vaccine products manufactured by sanofi pasteur were unaffected by the recall. Yet despite efforts to boost production of those vaccines to help alleviate the shortfall, it's unlikely sanofi pasteur will be able to provide sufficient additional Hib vaccine to fully meet demand.

Within a week of the Merck recall announcement, the CDC, in consultation with its Advisory Committee on Immunization Practices, or ACIP, the AAFP and the AAP, issued interim recommendations for Hib immunization. Those recommendations call for vaccine providers to temporarily defer the Hib booster dose normally given at age 12-15 months except for children in specific high-risk groups, such as those with asplenia, sickle cell disease or HIV infection and certain other immunodeficiency syndromes, as well as children who have malignant neoplasms.

In addition, American Indian and Alaska Native children, who are at increased risk for invasive Hib disease, still should receive the booster dose, according to the interim recommendations.

Health care professionals should track children in whom the Hib booster dose is deferred so they can be recalled for immunization when the current supply disruption improves.

According to Jonathan Temte, M.D., Ph.D., one of the Academy's two liaisons to the ACIP, it's not surprising that such interim immunization recommendations may be overlooked in a busy family medicine clinic, particularly when a practice has a plentiful supply of the vaccine in question.

An associate professor in the department of family medicine at the University of Wisconsin, Madison, Temte explained what he found in his own clinic when he took a good look at how Hib immunizations were being handled in the wake of the new recommendations.

"Because we had Hib in abundance, our vaccine coordinator really didn't feel that the guidance applied and was worried that deferring would cause lots of problems for call-backs in the future," Temte noted. Once the coordinator realized there was an issue, it was relatively simple to address, Temte added. Still, Temte's experience illustrates the inherent struggle to balance community and national perspectives when it comes to making decisions about immunizations.

"I think it is increasingly difficult for clinics to keep track of shortages, delays and deferrals, and it is very understandable for decisions to be made in reference to local trends, with a lack of awareness of the national priorities," Temte said. "Coordinated and redundant efforts from CDC, state public health entities, and medical organizations, such as AAFP, are essential in maintaining health care safety and equity."

Further information on the Hib vaccine supply is available from the CDC's "Vaccine Shortages & Delays" Web page. To help reinforce the temporary deferral message, the CDC has created a flier (1-page PDF; About PDFs) family physicians can post in their offices as a reminder of the shortage to other health care professionals and staff members.