Haemophilus influenzaetype b infection, vaccination, andH. influenzaecarriage in children in Minnesota, 2008–2009

Abstract

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.

InvasiveHaemophilus influenzaeSerotype e and f Disease, England and Wales

“…Because conjugate vaccines also reduce pharyngeal carriage ( 4 ), concerns have been raised that other H. influenzae strains could fill the ecologic niche and result in invasive disease (serotype replacement) ( 5 ), although no studies have demonstrated increased carriage rates of other H. influenzae serotypes after routine Hib vaccination ( 6 ). Some countries have reported small but significant increases in invasive ncHi disease after routine Hib vaccination ( 7 – 10 ); others have not ( 11 , 12 ).…”

Evaluation of New Biomarker Genes for Differentiating Haemophilus influenzae from Haemophilus haemolyticus

“…The hpd assay is highly specific for H. influenzae and provides a potential tool to differentiate H. influenzae from H. haemolyticus, including nonhemolytic H. haemolyticus. In this study, both hpd and fucK PCR assays were evaluated against 16S rRNA gene phylogeny for distinguishing H. influenzae from H. haemolyticus by the use of Haemophilus isolates identified during a carriage study in Minnesota (12,22 All isolates were further characterized using the hpd and fucK PCR assays with crude DNA as the template (28). All of the 31 hemolytic H. haemolyticus and 128 other Haemophilus species isolates were negative by both hpd and fucK PCR assays.…”

Are we speaking the same language? an argument for the consistent use of terminology and definitions for childhood vaccination indicators

“…The indicator vaccination rate is often used interchangeably with vaccine coverage in the research literature, but is rarely explicitly defined. 9,20,[26][27][28]32,38,[41][42][43][44] It is usually synonymous with coverage, e.g. "the vaccination rates are calculated from the numbers of vaccinated persons over the respective populations" 7 or in a paper by Ernst et al, 45 where they state that changes in vaccination coverage by region are reported as vaccination rate per 100,000 children.…”