Tamiflu benefits swine flu patients

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Healthy people who caught swine flu during the 2009 pandemic may have been protected against developing pneumonia by taking the antiviral drug oseltamivir (Tamiflu), a new study has concluded.

The researchers also found that oseltamivir treatment was associated with shorter duration of fever and viral RNA shedding, although they stressed that their findings should be interpreted with caution.

Trials carried out on seasonal flu viruses have shown that taking antiviral drugs within 48 hours of symptom onset can reduce the severity and duration of symptoms, and possibly the risk of complications. However, the extent to which antivirals may benefit otherwise healthy individuals with mild 2009 H1N1 infection remains unknown.

Researchers reviewed the medical records of 1,291 patients in China with mild H1N1 infection during the 2009 pandemic. The average age of patients was 20 years. Three quarters of patients were treated with oseltamivir from a median of the third day of symptoms. Of 920 patients who had a chest x-ray, 12 per cent had abnormal findings consistent with pneumonia. No patients required ICU admission or mechanical ventilation.

Using statistical modelling of the patients? data, the researchers ruled out the effects of age, sex, influenza vaccination and treatment with antibiotics on the main study outcomes: getting pneumonia; having prolonged high fever; and viral RNA shedding. Oseltamivir treatment was then identified as a significant protective factor against subsequent development of pneumonia, confirmed by a chest x-ray. This protective effect was seen in all patients, including those who started treatment more than two days after onset of symptoms.

Oseltamivir treatment started within two days of symptom onset also reduced the duration of fever and viral RNA shedding. They also found that 2009 H1N1 might be shed longer than seasonal influenza virus.

The findings are consistent with patients with the 2009 H1N1 benefiting from use of oseltamivir, said the authors. However, they stressed that their finding that oseltamivir protected against subsequent radiographic pneumonia should be interpreted with caution, given the retrospective design of this work and that not all patients underwent chest x-ray.

http://www.imt.ie/clinical/2010/12/tamiflu-benefits-swine-flu-patients-–-new-study.html

 

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Re: Tamiflu benefits swine flu patients ? new study

Re: Tamiflu benefits swine flu patients ? new study

BMJ 2010; 341:c4779 doi: 10.1136/bmj.c4779 (Published 28 September 2010)
Cite this as: BMJ 2010; 341:c4779

Effectiveness of oseltamivir on disease progression and viral RNA shedding in patients with mild pandemic 2009 influenza A H1N1: opportunistic retrospective study of medical charts in China
This article has been UnlockedFree via Creative Commons: OPEN ACCess

1. Hongjie Yu, medical epidemiologist/deputy director1,
2. Qiaohong Liao, public health officer1,
3. Yuan Yuan, respiratory physician2,
4. Lei Zhou, public health officer1,
5. Nijuan Xiang, public health officer1,
6. Yang Huai, public health officer1,
7. Xiuhua Guo, professor3,
8. Yingdong Zheng, associate professor4,
9. H Rogier van Doorn, clinical microbiologist5,
10. Jeremy Farrar, professor5,
11. Zhancheng Gao, professor/respiratory physician2,
12. Zijian Feng, medical epidemiologist/director1,
13. Yu Wang, professor/director6,
14. Weizhong Yang, medical epidemiologist/deputy director6


Abstract

Objective To describe the clinical features and effectiveness of oseltamivir on disease progression and viral RNA shedding in patients with mild pandemic 2009 influenza A(H1N1) virus infection.

Design Opportunistic retrospective review of medical charts of patients with confirmed 2009 H1N1 identified through the national surveillance system in China from May to July 2009.

Setting Under coordination of the Ministry of Health, local health departments were asked to collect medical records of confirmed patients and send them to the Chinese Centre for Disease Control and Prevention on a voluntary basis as part of the public health response.

Population 1291 patients with confirmed 2009 H1N1 infection and available data for chart review.

Main outcome measures Demographic characteristics, comorbidities, symptoms and signs, laboratory tests, findings on chest radiography, antiviral treatment, duration of fever, and duration of viral RNA shedding.

Results The median age of 1291 patients was 20 years (interquartile range 12-26); 701 (54%) were male. The most common symptoms were fever (820, 64%), cough (864, 67%), sore throat (425, 33%), sputum (239, 19%), and rhinorrhoea (228, 18%). Of 920 patients who underwent chest radiography, 110 (12%) had abnormal findings consistent with pneumonia. Some 983 (76%) patients were treated with oseltamivir from a median of the third day of symptoms (2-4). No patients required admission to the intensive care unit or mechanical ventilation. 2009 H1N1 was shed from one day before onset of symptoms to up to eight days after onset in most (91%) patients, with a median of 5 (3-6) days of shedding after onset. Treatment with oseltamivir significantly protected against subsequent development of radiographically confirmed pneumonia (odds ratio 0.12, 95% confidence interval 0.08 to 0.18), and treatment started within two days of symptom onset reduced the duration of fever and viral RNA shedding.

Conclusions Chinese patients with 2009 H1N1 infection predominantly presented with features of uncomplicated, self limiting acute respiratory illness. 2009 H1N1 might be shed longer than seasonal influenza virus. Treatment with oseltamivir was associated with a significantly reduced development of radiographically confirmed pneumonia and a shorter duration of fever and viral RNA shedding. Though these patients benefited from treatment, the findings should be interpreted with caution as the study was retrospective and not all patients underwent chest radiography.

full article

http://www.bmj.com/content/341/bmj.c4779.full?sid=069465cc-9d48-4811-81e4-fa9e16e86af0