Knowledge of interim recommendations and use of Hib vaccine during vaccine shortages.

OBJECTIVES: The goals were to determine among pediatricians and family physicians (1) knowledge of interim recommendations regarding Haemophilus influenzae type b (Hib) vaccine administration, (2) current practices, and (3) factors associated with nonadherence. METHODS: An Internet-based survey was conducted in April 2008 among national samples. RESULTS: Response rates were 68% (220 of 325 physicians) among pediatricians and 51% (153 of 302 physicians) among family physicians. Seventy-three percent of pediatricians and 45% of family medicine physicians reported insufficient Hib vaccine supplies, and 22% to 24% reported having to defer doses for infants 2 to 6 months of age > or =10% of the time. Ninety-eight percent of pediatricians and 81% of family physicians were aware of the interim recommendations (P < or = .0001), and virtually all knew that the booster dose should be deferred; however, 22% of pediatricians and 33% of family medicine physicians reported not deferring this dose. Physicians in both specialties were less likely to adhere to recommendations to defer in this age group if they thought that their practice had sufficient vaccine supplies (pediatricians, odds ratio: 0.01 [95% confidence interval: 0.003-0.03]; family medicine physicians, odds ratio: 0.10 [95% confidence interval: 0.03-0.33]). Family medicine physicians were less likely to adhere to recommendations if they had not heard about the interim recommendations (odds ratio: 0.04 [95% confidence interval: 0.01-0.21]). CONCLUSIONS: Most primary care physicians experienced Hib vaccine shortages, and many have had to defer doses for 2- to 6-month-old children. Most are knowledgeable regarding interim recommendations, but one-fifth to one-third reported nonadherence.

Continued shortage of Haemophilus influenzae Type b (Hib) conjugate vaccines and potential implications for Hib surveillance--United States, 2008.

In December 2007, Merck & Co., Inc. (West Point, Pennsylvania) announced a voluntary recall of certain lots of two Haemophilus influenzae type b (Hib) conjugate vaccines, PedvaxHIB (monovalent Hib vaccine) and Comvax (Hib-HepB vaccine) and suspended production of both vaccines, disrupting the U.S. supply of Hib vaccine. When the recall was announced, Merck projected restoration of these vaccines to the U.S. market in late 2008. To ensure that enough vaccine would be available for all U.S. children to complete the primary Hib vaccination series, on December 18, 2007, CDC recommended that providers defer the booster dose of Hib vaccine (scheduled for administration at age 12-15 months) for all children except those at increased risk for invasive Hib disease. On October 17, 2008, Merck announced that restoration of the two vaccines to the market would be delayed until mid-2009. Because the continued delay might result in an increase in Hib disease, national surveillance for invasive Hib disease has become particularly important. To assess the current status of surveillance for Hib nationally, CDC reviewed 4,657 cases of invasive H. influenzae infection reported during January 2007-October 2008, including 748 cases among children aged <5 years. Of those 748 cases, 45 (6.0%) were Hib (serotype b), and 278 (37.2%) were missing serotype information. The continued vaccine shortage heightens the need for timely reporting and investigation of H. influenzae cases and accurate serotyping of all invasive H. influenzae isolates in children aged <5 years.