Nolen LD, Topaz N, Miernyk K, Bressler S, Massay SC, Geist M, Zulz T, Singleton R. Evaluating a Cluster and the Overall Trend of Invasive Haemophilus influenzae Serotype b in Alaska 2005-2019.
Pediatr Infect Dis J 2022;
41:e120-e125. [PMID:
35067639 DOI:
10.1097/inf.0000000000003470]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND
In 2019, 5 cases of invasive Haemophilus influenzae serotype b (Hib) occurred in the Anchorage region of Alaska over a period of 16 days. No cases had occurred in Alaska in the preceding 26 months.
METHODS
Alaska Hib isolates from 2005 through 2019 were analyzed using whole-genome sequencing (WGS). Rates were compared with the CDC's Active Bacterial Core surveillance (ABCs) data.
RESULTS
A total of 33 cases of invasive Hib occurred in Alaska from 2005 through 2019. Of the 5 cases associated with the cluster, 2 (40%) occurred in adults and all occurred in the Anchorage region. In contrast, only 14% (4/28) of the noncluster cases occurred in this region (P < 0.01). Two cluster cases were linked epidemiologically and the bacteria were nearly identical. The other 3 cluster cases were caused by 3 genetically distinct bacteria. When the full period was evaluated, the unadjusted rate of invasive Hib disease in Alaska was 15.5 times higher in Alaska Native (AN) people than non-AN people [1.3/100,000 vs. 0.07/100,000, 95% confidence intervals (CI): 10.2-22.5). The age-adjusted rate of invasive Hib disease in Alaska was 9.4 times higher than the ABCs rate (95% CI: 6.3-14.1).
CONCLUSIONS
While clustered in time and space, the 5 cases in 2019 were not due to a single bacterial strain. AN people continue to have elevated rates of invasive Hib infection compared with both non-AN people in Alaska and the ABCs population.
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