Epidemiology and Infection

Haemophilus influenza b

Haemophilus influenzae type b infection, vaccination, and H. influenzae carriage in children in Minnesota, 2008–2009

S. A. LOWTHERa1a2 c1, N. SHINODAa2, B. A. JUNIa2, M. J. THEODOREa3, X. WANGa3, S. L. JAWAHIRa2, M. L. JACKSONa1a3, A. COHNa3, R. DANILAa2, R. LYNFIELDa2 and the Hib Survey Team

a1 Epidemic Intelligence Service, Division of Applied Sciences, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA

a2 Minnesota Department of Health (MDH), St Paul, MN, USA

a3 Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA


An increase in invasive Haemophilus influenzae type b (Hib) cases occurred in Minnesota in 2008 after the recommended deferral of the 12–15 months Hib vaccine boosters during a US vaccine shortage. Five invasive Hib cases (one death) occurred in children; four had incomplete Hib vaccination (three refused/delayed); one was immunodeficient. Subsequently, we evaluated Hib carriage and vaccination. From 18 clinics near Hib cases, children (aged 4 weeks–60 months) were surveyed for pharyngeal Hib carriage. Records were compared for Hib, diphtheria-tetanus-acellular pertussis (DTaP), and pneumococcal (PCV-7) vaccination. Parents completed questionnaires on carriage risk factors and vaccination beliefs. In 1631 children (February–March 2009), no Hib carriage was detected; Hib vaccination was less likely to be completed than DTaP and PCV-7. Non-type b H. influenzae, detected in 245 (15%) children, was associated with: male sex, age 24–60 months, daycare attendance >15 h/week, a household smoker, and Asian/Pacific Islander race/ethnicity. In 2009, invasive Hib disease occurred in two children caused by the same strain that circulated in 2008. Hib remains a risk for vulnerable/unvaccinated children, although Hib carriage is not widespread in young children.

(Accepted April 09 2011)

(Online publication May 18 2011)


† Members of Hib Survey Team are given in the Appendix.