title: Invasive Haemophilus influenzae serotype e and f disease, England and Wales.
abstract: Haemophilus influenzae infection causes serious invasive disease, but incidence of the most virulent serotype, Hib, has dropped since introduction of routine Hib vaccination. In England and Wales, the incidence of 2 other serotypes, Hie and Hif, is increasing; during 2001-2010, there was an 11.0% year-on-year increase in Hif and a 7.4% increase in Hie. In 2009-2010, Hif incidence was 0.090/100,000 persons and Hie incidence 0.030/100,000, with higher rates among infants and older adults. Hie had a more severe clinical course; although outcome at 6 months was comparable for the 2 serotypes, case-fatality rate within 7 days of diagnosis was higher for Hie, even after adjustment for age and comorbidities. Multilocus sequence typing revealed a single major circulating clone for both Hif (sequence type 124; 89/99 isolates, 90%) and Hie (sequence type 18; 21/33, 64%), but no association between type and clinical disease or outcome was found.
authors.affiliation: Health Protection Agency, London, UK. shamez.ladhani@hpa.org.uk
authors.forename: Shamez N
authors.initials: SN
authors.lastname: Ladhani
authors.forename: Sarah
authors.initials: S
authors.lastname: Collins
authors.forename: Anna
authors.initials: A
authors.lastname: Vickers
authors.forename: David J
authors.initials: DJ
authors.lastname: Litt
authors.forename: Carina
authors.initials: C
authors.lastname: Crawford
authors.forename: Mary E
authors.initials: ME
authors.lastname: Ramsay
authors.forename: Mary P E
authors.initials: MP
authors.lastname: Slack
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology*; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D012703:Serotyping; D014852:Wales / Q000453:epidemiology; D055815:Young Adult