International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Northern Epidemiology

Objectives: Rates of invasive pneumococcal disease and of otitis media among Inuit of the Arctic are among the highest in the world. To obtain knowledge of nasopharyngeal carriage and serotype distribution of pneumococci among Inuit children, we carried out a population-based cross-sectional study among unselected children in Sisimiut, the second-biggest town of Greenland.

Methods: Children eligible for enrolment were all non-acutely ill children attending 1-5th school class (5-11 years). A single nasopharyngeal specimen was obtained by a calcium alginate-tipped aluminium swab immediately inserted into serum broth and kept refrigerated until incubated after returning to Denmark within nine days. A pilot study had shown no loss of pneumococci with such an approach. Serotyping was done directly on the overnight incubated serum broth, using both the Pneumotest-latex kit and Neufelt’s test. After plating, single colonies were picked for antibiotic susceptibility testing by disk diffusion and E-test.

Results: Of 313 participating children 291 had a nasopharyngeal swab taken. Antibiotics had been taken by 38 children within the 3 previous months. Pneumococcal carriage was demonstrated in 133 children (46%), 118 (41%) children with and 15 (5%) with two strains. There was no sex difference in carriage rates, but a tendency of decreasing carriage with age from 60% among children aged 5-6 years to 41% among children aged 10-11 years. In total 22 different serotypes were identified with 7 serotypes accounting for 2/3 of isolates. Thirty-six percent of isolates were covered by the 7 and 9-valent pneumococcal conjugate vaccines, 50% by the 11-valent, and 70% by the 23-valent polysaccharide vaccine. All isolates were penicillin-susceptible.

Discussion: Compared with native children from Alaska, another high-incidence population, carriage rates among the Greenlandic children seems similar, but higher than among Danish children. Carriage of two serotypes was found at an equal rate (5%) among the Greenlandic children as among younger Danish children. Nine of the 22 carried serotypes (55% of isolates) were similar to serotypes from invasive disease cases in Greenlanders, serotypes previously found to be responsible for 43% of invasive cases.

Conclusions: Pneumococcal carriage among Greenlandic children is high and almost half of the carried serotypes are associated with invasive pneumococcal disease. Vaccines with population-specific serotype compositions seem necessary to sufficiently reduce pneumococcal carriage in Greenland.

Note. Abstracts are published in author's edition

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Last update: 06-Jul-2012 (11:52:05)