title: Neonatal invasive Haemophilus influenzae disease in England and Wales: epidemiology, clinical characteristics, and outcome.
abstract: BACKGROUND
  Nontypeable Haemophilus influenzae (NTHi) frequently causes noninvasive upper respiratory tract infections in children but can cause invasive disease, mainly in older adults. An increased burden of invasive NTHi disease in the perinatal period has been reported by a number of studies. Here we describe the epidemiology, clinical characteristics, and outcome of neonatal invasive H. influenzae disease in England and Wales over a 5-year period.
  
  
  METHODS
  Public Health England conducts enhanced national surveillance of invasive H. influenzae disease in England and Wales. Detailed clinical information was obtained for all laboratory-confirmed cases in infants aged ≤31 days during 2009-2013.
  
  
  RESULTS
  Overall, 118 live-born neonates had laboratory-confirmed invasive H. influenzae disease: 115 (97%) were NTHi, 2 were serotype f, and 1 was serotype b. NTHi was isolated within 48 hours of birth (early-onset) in 110 of 115 (96%) cases, and 70 of 110 (64%) presented with septicemia. Only 17 mothers (15%) had suspected bacterial infection requiring antibiotics during labor. Few (8/110 [7%]) neonates had comorbidities. The incidence of early-onset NTHi increased exponentially with prematurity, from 0.9 per 100 000 (95% confidence interval [CI], .6-1.4) in term neonates to 342 per 100 000 (95% CI, 233.9-482.7) in neonates born at <28 weeks' gestation (incidence rate ratio, 365 [95% CI, 205-659]; P < .001). Case fatality for early-onset NTHi was 19% (21/110); each additional gestational week reduced the odds of dying by 21% (odds ratio, 0.79 [95% CI, .69-.90]; P < .01). A quarter of neonates who survived experienced long-term complications.
  
  
  CONCLUSIONS
  Early-onset neonatal NTHi disease is strongly associated with premature birth and causes significant morbidity and mortality.
authors.affiliation: Immunisation, Hepatitis and Blood Safety Department.
authors.forename: Sarah
authors.initials: S
authors.lastname: Collins
authors.affiliation: Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom.
authors.forename: David J
authors.initials: DJ
authors.lastname: Litt
authors.affiliation: Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom.
authors.forename: Sally
authors.initials: S
authors.lastname: Flynn
authors.affiliation: Immunisation, Hepatitis and Blood Safety Department.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Ramsay
authors.affiliation: Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom.
authors.forename: Mary P E
authors.initials: MP
authors.lastname: Slack
authors.affiliation: Immunisation, Hepatitis and Blood Safety Department.
authors.forename: Shamez N
authors.initials: SN
authors.lastname: Ladhani
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D004739:England / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006192:Haemophilus Infections / Q000453:epidemiology*; D006193:Haemophilus influenzae; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology*; D008297:Male; D011247:Pregnancy; D016896:Treatment Outcome; D014852:Wales / Q000453:epidemiology; D055815:Young Adult
keywords: Haemophilus influenzae; epidemiology; neonatal; outcome