Epidemiology of invasive H. influenzae infections in Greenland 1995-2013 – a nationwide study
METHODS: Nation-wide cohort study using complete information on bacterial isolates from Greenland 1995-2013 and the total population of Greenland (N 56,000) identified through the unique personal identification number. Health information retrieved from medical files.
RESULTS: Invasive Hi was identified in 15 patients in total (1995-1999 N=9; 2000-2004 N=4; 2005-2009 N=1; 2010-2013 N=1); seven cases from blood, five from cerebrospinal fluid, one from both, and two from pleural fluid. Median age of cases was 1 year (range 0 – 71 years; 25 and 75% quartiles 0 and 33 years; 53% females). Overall incidence 1995-2013 was 1.4/100,000 (2000-2013 0.76/100,000); for children aged 0-4 years 10.2/100,000 (2000-2013 3.3/100,000). Seven isolates were Hib (four before 1997 and three after); one was serotype f; one was non-capsular, two were not characterized by capsule, and for four there was no information on type. In comparison, the incidence of invasive pneumococcal disease increased in the period 1995-2013.
CONCLUSIONS: The incidence of invasive Hi infections is decreasing in Greenland, and no Hi outbreaks have been observed 1995-2013. Cases of non-b serotypes are very rare. A present need for introduction of non-Hib vaccines in the Greenlandic population is not supported.