Abstract
Purpose
Reliable and rapid diagnosis of influenza A H1N1 is essential to initiate the appropriate antiviral therapy and preventive measures. As PCR assays are time-consuming and rapid antigen tests have a limited sensitivity, official influenza case definitions are used in many clinical settings. These, however, are based exclusively on clinical criteria and have only a moderate potential to differentiate between influenza and other febrile diseases. Only limited data on the differences in clinical and laboratory parameters between influenza and non-influenza febrile diseases are available to date.
Methods
This was a retrospective case-negative control series that was conducted in Styria, southeast Austria. We analyzed the differences in clinical presentation and laboratory admission parameters between patients with PCR-confirmed H1N1 influenza infection (n = 199) and those with influenza-like disease and negative influenza PCR results (ILD group; n = 252).
Results
In the multivariable analysis lower C-reactive protein (CRP) level, lower white blood cell (WBC) count, fever, wheezing, cough, and the absence of nausea or sudden onset remained significant predictors of H1N1 influenza in adult patients (n = 263). Lower CRP level, lower WBC count, and cough remained significant predictors in pediatric patients (<16 years; n = 188).
Conclusion
Lower CRP level, lower WBC count, and cough were significant predictors of H1N1 in both the adult and pediatric patient group. These data may help to develop an improved case definition for suspected H1N1 infection which combines clinical findings and easily available laboratory parameters.
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References
Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team, Dawood FS, Jain S, et al. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med. 2009;360:2605–15.
van den Wijngaard CC, van Asten L, Koopmans MP, et al. Comparing pandemic to seasonal influenza mortality: moderate impact overall but high mortality in young children. PLoS One. 2012;7:e31197.
Kumar A, Zarychanski R, Pinto R, et al. Critically ill patients with 2009 influenza A (H1N1) infection in Canada. JAMA. 2009;302:1872–9.
ANZIC Influenza Investigators, Webb SA, Pettila V, et al. Critical care services and 2009 H1N1 influenza in Australia and New Zealand. N Engl J Med. 2009;361:1925–34.
Louie JK, Acosta M, Jamieson DJ, Honein MA, California Pandemic (H1N1) Working Group. Severe 2009 H1N1 influenza in pregnant and postpartum women in California. N Engl J Med. 2010;362:27–35.
Pierangeli A, Scagnolari C, Selvaggi C, et al. Virological and clinical characterization of respiratory infections in children attending an emergency department during the first autumn-winter circulation of pandemic A (H1N1) 2009 influenza virus. Clin Microbiol Infect. 2012;18:366–73.
Centers for Disease Control and Prevention. Infectious disease. Antiviral agents for the treatment and chemoprophylaxis of influenza. Ann Emerg Med. 2011;58:299–303 (discussion 303–4).
Poeppl W, Herkner H, Burgmann H, et al. Performance of the QuickVue influenza A + B rapid test for pandemic H1N1 (2009) virus infection in adults. PLoS One. 2011;6:e28089.
Boivin G, Hardy I, Tellier G, Maziade J. Predicting influenza infections during epidemics with use of a clinical case definition. Clin Infect Dis. 2000;31:1166–9.
Woolpert T, Brodine S, Lemus H, Waalen J, Blair P, Faix D. Determination of clinical and demographic predictors of laboratory-confirmed influenza with subtype analysis. BMC Infect Dis. 2012;12:129.
Hirve S, Chadha M, Lele P, et al. Performance of case definitions used for influenza surveillance among hospitalized patients in a rural area of India. Bull World Health Organ. 2012;90:804–12.
Chan PA, Mermel LA, Andrea SB, et al. Distinguishing characteristics between pandemic 2009–2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness. PLoS One. 2011;6:e24734.
Perez-Padilla R, de la Rosa-Zamboni D, de Ponce Leon S, et al. et al. Pneumonia and respiratory failure from swine-origin influenza A (H1N1) in Mexico. N Engl J Med. 2009;361:680–9.
Lessler J, Reich NG, Cummings DA, et al. Outbreak of 2009 pandemic influenza A (H1N1) at a New York City school. N Engl J Med. 2009;361:2628–36.
Jain S, Kamimoto L, Bramley AM, et al. Hospitalized patients with 2009 H1N1 influenza in the United States, April–June 2009. N Engl J Med. 2009;361:1935–44.
Lee IK, Liu JW, Wang L, Yang KD, Li CC, Eng HL. 2009 pandemic influenza A (H1N1): clinical and laboratory characteristics in pediatric and adult patients and in patients with pulmonary involvement. Influenza Other Respi Viruses. 2012;6:e152–61.
Cao B, Li XW, Mao Y, et al. Clinical features of the initial cases of 2009 pandemic influenza A (H1N1) virus infection in China. N Engl J Med. 2009;361:2507–17.
Rodriguez-Valero M, Prado Calleros HM, Bravo Escobar GA, et al. Difference between early clinical features of swine origin A H1N1 influenza confirmed and not confirmed infection in Mexico. J Infect Dev Ctries. 2012;6:302–10.
Poeppl W, Hell M, Herkner H, et al. Clinical aspects of 2009 pandemic influenza A (H1N1) virus infection in Austria. Infection. 2011;39:341–52.
Suess T, Buchholz U, Dupke S, et al. Shedding and transmission of novel influenza virus A/H1N1 infection in households–Germany, 2009. Am J Epidemiol. 2010;171:1157–64.
Myles PR, Semple MG, Lim WS, et al. Predictors of clinical outcome in a national hospitalised cohort across both waves of the influenza A/H1N1 pandemic 2009–2010 in the UK. Thorax. 2012;67:709–17.
Ramakrishna K, Peter JV, Karthik G, et al. Influenza A (H1N1) 2009 pandemic: was there a difference in the two waves in patients requiring admission to the intensive-care unit? Clin Microbiol Infect. 2011;17:1355–8.
Zarogoulidis P, Glaros D, Kioumis I, et al. Clinical differences between influenza A (H1N1) virus and respiratory infection between the two waves in 2009 and 2010. Int J Gen Med. 2012;5:675–82.
Mahony AA, Cheng AC, Olsen KL, et al. Diagnosing swine flu: the inaccuracy of case definitions during the 2009 pandemic, an attempt at refinement, and the implications for future planning. Influenza Other Respi Viruses. 2012;7:403–9.
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This study was conducted as part of our clinical work. No extra funding was obtained.
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Hoenigl, M., Prattes, J., Drescher, M. et al. Comparison of clinical presentation and laboratory values at admission between PCR-confirmed influenza A H1N1 infection and influenza-like disease, South-East Austria. Infection 42, 317–324 (2014). https://doi.org/10.1007/s15010-013-0549-1
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DOI: https://doi.org/10.1007/s15010-013-0549-1