Clinical Aspects of H1N1 Influenza A Infection
submited by kickingbird at Oct, 15, 2009 10:41 AM from CBN
Several research reports detailing aspects of infection with the pandemic strain of influenza have recently been released. These reports describing clinically relevant aspects of cases are useful for day-to-day management of pandemic influenza.
Details on Hospitalization of U.S. Patients
The New England Journal of Medicine´s summary of data on U.S. patients hospitalized with H1N1
- 25% of hospitalized patients required intensive care, 65% of whom required mechanical ventilation;
- 40% of patients undergoing chest radiography had evidence of pneumonia;
- 75% of patients were treated with antiviral medications;
- 79% of patients received antibiotics, mostly before or at admission;
- 93% of patients were discharged; 7% of patients died;
- Multivariate analysis revealed that those who received antiviral therapy within 2 days of symptom onset were significantly more likely to experience a positive outcome.
Bacterial Co-infection Seen in Less than 30% of Fatal Cases
Like seasonal influenza and past pandemics, a significant percentage of influenza related pneumonia involved bacterial co-infection, according to the October 2, 2009, MMWR.
|Streptococcus pneumoniae (pneumococcus)||45%|
|Streptococcus pyogenes (Group A streptococcus)||27%|
|Streptococcus mitis (viridians group streptococci)||9%|
Interesting Clinical Presentations
With the accumulation of case data, unusual presentations of influenza are also being discovered, such as an IgG subclass deficiency in many patients with severe disease identified by Lindsay Grayson and colleagues and revealed in San Francisco at the 2009 ICAAC meeting. This finding raises the question of potential benefit from IVIG infusion.
Understanding of Influenza Disease Has Expanded Substantially
As such reports accumulate, they will help paint a more detailed picture of severe influenza and the spectrum of disease to be expected during a pandemic. And each report provides more evidence for clinicians to use in managing H1N1 influenza (A) in individual patients, and for policymakers apply in managing this pandemic for the nation.
- Jain S, Kamimoto L, Bramley AM, et al. Hospitalized patients with 2009 H1N1 influenza in the United States, April鈥揓une 2009. NEJM 2009. http://content.nejm.org/cgi/content/full/NEJMoa0906695. Accessed October 12, 2009.
- CDC. Bacterial coinfections in lung tissue specimens from fatal cases of 2009 pandemic influenza A (H1N1)鈥擴nited States, May-August 2009. MMWR 2009. 58:1071-1074. http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm5838a4.htm. Accessed October 12, 2009.
- ProMED-mail. Influenza pandemic (H1N1) 2009 (51): antibody deficiency. September 17, 2009. http://www.promedmail.org/pls/otn/f?p=2400:1001:57555::::F2400_P1001_BACK_PAGE,F2400_P1001_
ARCHIVE_NUMBER,F2400_P1001_USE_ARCHIVE:1001,20090917.3261,Y. Accessed October 12, 2009.
- Wiebe C, Reslerova M, Komenda P, et al. Atypical clinical presentation of H1N1 influenza in a dialysis patient. Lancet 2009. 374:1300.
- WOAH: Influenza A viruses of high pathogenicity (Infection with H5N1) (non-poultry including wild birds) (2017-), China Aug, 1, 2022
- China: Confirmed human case of avian influenza A(H9N2) reported in Sichuan province Jun, 29, 2022
- China: A human case of avian influenza A(H5N6) reported in Jiangxi province Jun, 27, 2022
- China: Confirmed human cases of avian influenza A(H9N2) reported in Hunan and Guizhou province Jun, 9, 2022
- China: Confirmed human case of avian influenza A(H3N8) reported in Hunan province Jun, 1, 2022