Open AccessSevere acute respiratory infections caused by 2009 pandemic influenza A ( H 1 N 1) among A merican I ndians—southwestern U nited S tates, M ay 1– J uly 21, 2009
Author(s) -
Suryaprasad Anil,
Redd John T.,
Hancock Kathy,
Branch Alicia,
StewardClark Evelene,
Katz Jacqueline M.,
Fry Alicia M.,
Cheek James E.
Publication year - 2013
Publication title -
influenza and other respiratory viruses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.743
H-Index - 57
eISSN - 1750-2659
pISSN - 1750-2640
DOI - 10.1111/irv.12123
Subject(s) - medicine , odds ratio , confidence interval , pandemic , covid-19 , disease , infectious disease (medical specialty)
Background During April–July 2009, U.S. hospitalization rates for 2009 pandemic influenza A ( H 1 N 1) virus ( H 1 N 1pdm09) infection were estimated at 4·5/100 000 persons. We describe rates and risk factors for H 1 N 1pdm09 infection among A merican I ndians ( AI s) in four isolated southwestern U.S. communities served by the I ndian H ealth S ervice ( IHS ). Methods We reviewed clinical and demographic information from medical records of AI s hospitalized during M ay 1– J uly 21, 2009 with severe acute respiratory infection ( SARI ). Hospitalization rates were determined using denominator data provided by IHS . H 1 N 1pdm09 infection was confirmed with polymerase chain reaction, rapid tests, or convalescent serology. Risk factors for more severe ( SARI ) versus milder [influenza‐like illness ( ILI )] illness were determined by comparing confirmed SARI patients with outpatients with ILI . Results Among 168 SARI‐hospitalized patients, 52% had confirmed H 1 N 1pdm09 infection and 93% had >1 high‐risk condition for influenza complications. The H 1 N 1pdm09 SARI hospitalization rate was 131/100 000 persons [95% confidence interval (CI), 102–160] and was highest among ages 0–4 years (353/100 000; 95% CI, 215–492). Among children, asthma (adjusted odds ratio [a OR ] 3·2; 95% CI, 1·2–8·4) and age <2 years (a OR 3·8; 95% CI, 1·4–10·0) were associated with H 1 N 1pdm09 SARI‐associated hospitalization, compared with outpatient ILI. Among adults, diabetes (a OR 3·1; 95% CI, 1·5–6·4) was associated with hospitalization after controlling for obesity. Conclusions H 1 N 1pdm09 hospitalization rates among this isolated AI population were higher than reported for other U.S. populations. Almost all case patients had high‐risk health conditions. Prevention strategies for future pandemics should prioritize AI s, particularly in isolated rural areas.