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

Seminar Infection Diseases in Arctic

Rates of invasive pneumococcal disease (IPD) among indigenous peoples in Alaska (Alaska Natives (AN)) have historically been elevated compared with non-Native Alaskans. Since pneumococcal conjugate vaccine (PCV7) introduction in 2001, the rate of vaccine-type (VT) IPD among AN < 2 year-olds fell 96% (275 cases/100,000 (1995-00) to 11 cases/100,000 (2004-5)). This has eliminated the health disparity for VT IPD in AN children. However, recent increases in non-VT IPD have been observed among AN.

Cases were ill persons who had pneumococci isolated from a normally sterile site. Rates were obtained from statewide laboratory-based surveillance. Confirmed isolates were serotyped by the Quellung reaction. Proportions were compared using the chi-square test and trends in Poisson rates were evaluated with exact statistics.

Since 2001 the rate of non-VT IPD among AN < 2 year-olds has increased each year (38/100,000 in 2001 to 245/100,000 in 2005, P =0.003 for trend). No increase in non-VT IPD was seen for AN 2-4 year olds or non-Native children < 5 years old. Among AN < 2 year-olds, six serotypes (3, 10A, 15B, 15C, 19A, 38) caused an increased proportion of non-VT IPD since PCV7 use (20% prevaccine to 52% postvaccine, P=0.01). Overall IPD rates (all serotypes) for AN < 2 year-olds decreased from 403/100000 (prevaccine) to a low of 112/100,000 (2001-2) but increased to 53% of the prevaccine rate (216/100,000 in 2003-5, p=0.04).

The increased non-VT IPD rates among AN children under two years old have begun to erode the gains made in pneumococcal disease prevention through PCV7 use. If this trend continues, approaches other than PCV7 vaccine will be needed to prevent IPD in this population and to address the pneumococcal disease disparity suffered by AN

Note. Abstracts are published in author's edition

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