Are Primary Care Physicians Following Interim Recommendations for the Use of Haemophilus Influenzae Type B (Hib) Vaccine during Shortages?

Background:
In response to Hib vaccine shortages beginning in Dec 2007, interim recommendations were issued to defer the Hib booster for healthy 12-15 month olds. Recently Merck announced they do not anticipate their supply of Hib vaccine to return to the market until mid-2009.

Objectives:
To determine among pediatric (Peds) and family medicine (FM) physicians: 1) knowledge and attitudes about interim recommendations; 2) current practice regarding Hib administration; and 3) factors associated with adherence to recommendations.

Methods:
An internet-based survey was conducted in April 2008 among a national sample of 325 Peds and 302 FM.

Results:
Response rates were 68% in Peds and 51% in FM. Seventy-two percent of Peds and 42% of FM reported having insufficient supplies of Hib. Of Peds and FM physicians, 98% and 81%, respectively, were aware of interim recommendations (p=<0.0001). Of those who were aware, 100% of Peds and 99% of FM knew that the booster dose should be deferred according to recommendations. Despite this, 20% of physicians in each specialty reported not deferring vaccine in healthy 12-15 month olds. Physicians were less likely to adhere to recommendations if they believed that their practice had sufficient supplies of Hib vaccine [OR 0.02, CI (0.01-0.05)] or if they believed that their patients would not be adequately protected until they receive their booster dose [OR 0.33, CI (0.15-0.73)].

Conclusions:
The majority of primary care physicians were knowledgeable about interim Hib recommendations, but approximately one-fifth were non-adherent. Physicians who were non-adherent may be interpreting recommendations in the context of their own vaccine supplies and also cited concerns about adequacy of protection without the booster dose. In view of likely continued Hib shortages, there is a need for better clarification of recommendations and a need to better address physician concerns about following them.