Pulmonary complications of interpandemic influenza A in hospitalized adults
Yoshihiko Murata1, Edward E Walsh, Ann R Falsey
1Department of Medicine, University of Rochester School of Medicine and Dentistry and Infectious Diseases Unit, Department of Medicine, Rochester General Hospital, Rochester, NY 14621, USA. Yoshihiko.Murata@viahealth.org
Background:
To define the pulmonary complications of influenza during the current interpandemic period, we reviewed clinical, laboratory, and radiographic data from 193 adults (> or =18 years old) (1999-2003) who were hospitalized with influenza A during 4 winters.
Results:
The mean age was 75 years, 8% had documented bacterial infection, 15% required intensive care unit treatment, and 6% died. Chest radiograph (CXR) findings were classified as showing acute disease (AD; n=101) or no AD (NAD; n=92). Most CXR findings were subtle in nature. Subjects with AD were more likely to have > or =1 cardiac diagnosis (odds ratio [OR], 2.2 [95% confidence interval {CI}, 1.2-4.1]), to have rales on examination (OR, 1.9 [95% CI, 1.0-3.7]), to be symptomatic for >3 days (OR, 2.2 [95% CI, 1.2-4.1]), and to be less likely to wheeze (OR, 0.37 [95% CI, 0.20-0.70]). Total and neutralizing anti-influenza antibody titers were lower in patients with influenza than in respiratory syncytial virus-infected control subjects (P<.05), which suggests a protective effect of antibody. Interestingly, antibody titers did not differ between subjects with AD and those with NAD.
Conclusion:
In the absence of significant antigenic shifts, previous exposure to influenza, including vaccinations, may play a role in reducing the severity of influenza-associated lower respiratory tract disease.
Insights
Previous influenza exposure, including vaccinations, may reduce lower respiratory tract disease severity during interpandemic periods. This study analyzed pulmonary complications in hospitalized adults with influenza A.
Area of Science:
- Pulmonology
- Infectious Diseases
- Epidemiology
Background:
- Investigated pulmonary complications of influenza A during interpandemic periods (1999-2003).
- Included 193 hospitalized adults (≥18 years old).
Purpose of the Study:
- To define pulmonary complications of influenza A.
- To assess factors influencing disease severity.
Main Methods:
- Retrospective review of clinical, laboratory, and radiographic data.
- Chest radiography (CXR) classified as acute disease (AD) or no acute disease (NAD).
- Analysis of patient demographics, comorbidities, and outcomes.
Main Results:
- Mean age 75 years; 6% mortality.
- AD associated with cardiac diagnosis, rales, and longer symptom duration (>3 days).
- Lower anti-influenza antibody titers suggested a protective effect.
Conclusions:
- Previous influenza exposure, including vaccination, may mitigate lower respiratory tract disease severity.
- Antibody titers did not correlate with CXR findings (AD vs. NAD).
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