title: Increased disease due to Haemophilus influenzae type b: population-based surveillance in eastern Gambia, 2008-2013.
abstract: BACKGROUND
  In 1997, The Gambia became the first African country to introduce conjugate Haemophilus influenzae type b (Hib) vaccine with good disease control through to 2010.
  
  
  METHODS
  Culture-based surveillance for invasive bacterial disease in eastern Gambia, specifically the Basse Health and Demographic Surveillance System (BHDSS) area, was conducted from 12 May 2008 and in Fuladu West district from 12 September 2011 until 31 December 2013. In 2011, Hib serology was measured in 5-34-year-olds.
  
  
  RESULTS
  In all, 16,735 of 17,932 (93%) eligible patients were investigated. We detected 57 cases of invasive H. influenzae disease; 24 (42%) were type b. No cases of Hib disease were detected in the BHDSS area in 2008-2009; 1 was detected in 2010, 2 in 2011, 4 in 2012 and 7 in 2013. In 2013, the incidence of Hib disease in those aged 2-11 and 2-59 months in the BHDSS area was 88 [95% confidence interval (CI): 29-207] and 22 (95% CI: 9-45) cases per 10⁵ person-years, respectively. In 2013, disease incidence in Fuladu West among those aged 0-59 months was 26 (95% CI: 7-67) cases per 10⁵ person-years. Nine of 24 Hib cases were vaccine failures (2 HIV positive) and 9 were too young to have been vaccinated. The proportion of children aged 5-6 years (n = 223) with anti-Hib IgG ≥1.0 μg/mL was 67%; the antibody nadir was in 9-14-year-olds (n = 58) with 55% above threshold.
  
  
  CONCLUSIONS
  Hib disease in eastern Gambia has increased in recent years. Surveillance in developing countries should remain alert to detect such changes.
authors: From the *Medical Research Council, The Gambia Unit, The Gambia; †Murdoch Childrens Research Institute, Parkville, Melbourne, Australia; ‡Ministry of Health and Social Welfare, Gambia Government, The Quadrangle, Banjul, The Gambia; §London School of Hygiene and Tropical Medicine, London, United Kingdom; and ¶ University of Otago, Dunedin, New Zealand.
authors: Grant A
authors: GA
authors: Mackenzie
authors: Usman N A
authors: UN
authors: Ikumapayi
authors: Susana
authors: S
authors: Scott
authors: Olubukola
authors: O
authors: Idoko
authors: Aderonke
authors: A
authors: Odutola
authors: Malick
authors: M
authors: Ndiaye
authors: Shah M
authors: SM
authors: Sahito
authors: Chidiebereh D
authors: CD
authors: Osuorah
authors: Ahmed
authors: A
authors: Manjang
authors: Sheikh
authors: S
authors: Jarju
authors: Abdoulie
authors: A
authors: Bojang
authors: Anna
authors: A
authors: Roca
authors: Ousman
authors: O
authors: Secka
authors: Akram
authors: A
authors: Zaman
authors: Lamin
authors: L
authors: Ceesay
authors: Yamundow
authors: Y
authors: Lowe-Jallow
authors: Sana
authors: S
authors: Sambou
authors: Momodou
authors: M
authors: Jasseh
authors: Martin
authors: M
authors: Antonio
authors: Brian
authors: B
authors: Greenwood
authors: Beate
authors: B
authors: Kampmann
authors: Kim
authors: K
authors: Mulholland
authors: Tumani
authors: T
authors: Corrah
authors: Stephen R C
authors: SR
authors: Howie
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D016667:Bacterial Capsules / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005714:Gambia / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D018073:Haemophilus Vaccines / Q000008:administration & dosage* / Q000276:immunology; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D007114:Immunization / Q000706:statistics & numerical data; D015994:Incidence; D011159:Population Surveillance; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine