Dataset Information

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.

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.

SUBMITTER: Yu H

PROVIDER: S-EPMC2947622 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

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Publications

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.

Yu Hongjie H Liao Qiaohong Q Yuan Yuan Y Zhou Lei L Xiang Nijuan N Huai Yang Y Guo Xiuhua X Zheng Yingdong Y van Doorn H Rogier HR Farrar Jeremy J Gao Zhancheng Z Feng Zijian Z Wang Yu Y Yang Weizhong W

BMJ (Clinical research ed.) 20100928

<h4>Objective</h4>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.<h4>Design</h4>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.<h4>Setting</h4>Under coordination of the Ministry of Health, local health departments were asked to collect me ...[more]

PMID: 20876641

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Project description:Pandemic (H1N1) 2009 influenza is affecting countries in all five continents, with most cases so far having been reported in North and South America and Europe, and children and young adults being the most susceptible age groups. To date, the clinical course of disease is typically mild, with low hospitalization and mortality rates. Pandemic (H1N1) 2009 is susceptible to oseltamivir and, although few clinical data are yet available, current information suggests that treatment with oseltamivir appears to be beneficial. Only isolated cases of resistance to the drug have been reported to date, in keeping with the low frequency observed in clinical studies involving patients infected with seasonal influenza viruses. Current health authority guidelines recommend the use of oseltamivir in infected adults and children who have or are at elevated risk for severe disease, including pregnant women; use during the pandemic in infants < 1 year has also been authorized in Europe and a number of other countries, including the USA and Canada. Before the onset of the current pandemic, F. Hoffmann-La Roche Ltd expanded annual production capacity for oseltamivir to 400 million treatment courses per year to meet anticipated demand. However, during an influenza pandemic, and despite increased production capabilities, resources are nonetheless likely to be initially in short supply. For this reason, Roche, in line with WHO recommendations, has advocated advance stockpiling of antivirals by governments as a pandemic preparedness measure. Between 2004 and December 2009, 350 million treatment courses were supplied to governments worldwide. Support for developing countries has been a priority. Roche has established a cluster of initiatives aimed at increasing access to Tamiflu for the world's developing economies, including, making donations to the WHO, establishing the Tamiflu Reserves Program (TRP) and sub-licensing and manufacturing contracts with local companies in Asia and Africa. Furthermore, Roche has published a document outlining how it would allocate limited supplies of Tamiflu during a pandemic, which are in line with WHO recommendations stating that 'resources should be used to provide the maximum possible health benefit'. Roche is also offering support such as reprocessing of expiring capsule stocks (in development) and shelf-life extension to support governments in the management of their stockpiles. Clinical studies, either sponsored by or supported by Roche, are in progress. These trials are designed to investigate the effectiveness of oseltamivir in patients infected with the pandemic virus in greater depth, and include high-dose studies, assessment of natural and drug-induced resistance, and response to treatment in high-risk populations such as young infants, immunocompromised patients and the severely ill.

Project description:The neuraminidase (NA) inhibitor oseltamivir offers an important immediate option for the control of influenza, and its clinical use has increased substantially during the recent H1N1 pandemic. In view of the high prevalence of oseltamivir-resistant seasonal H1N1 influenza viruses in 2007-2008, there is an urgent need to characterize the transmissibility and fitness of oseltamivir-resistant H1N1/2009 viruses, although resistant variants have been isolated at a low rate. Here we studied the transmissibility of a closely matched pair of pandemic H1N1/2009 clinical isolates, one oseltamivir-sensitive and one resistant, in the ferret model. The resistant H275Y mutant was derived from a patient on oseltamivir prophylaxis and was the first oseltamivir-resistant isolate of the pandemic virus. Full genome sequencing revealed that the pair of viruses differed only at NA amino acid position 275. We found that the oseltamivir-resistant H1N1/2009 virus was not transmitted efficiently in ferrets via respiratory droplets (0/2), while it retained efficient transmission via direct contact (2/2). The sensitive H1N1/2009 virus was efficiently transmitted via both routes (2/2 and 1/2, respectively). The wild-type H1N1/2009 and the resistant mutant appeared to cause a similar disease course in ferrets without apparent attenuation of clinical signs. We compared viral fitness within the host by co-infecting a ferret with oseltamivir-sensitive and -resistant H1N1/2009 viruses and found that the resistant virus showed less growth capability (fitness). The NA of the resistant virus showed reduced substrate-binding affinity and catalytic activity in vitro and delayed initial growth in MDCK and MDCK-SIAT1 cells. These findings may in part explain its less efficient transmission. The fact that the oseltamivir-resistant H1N1/2009 virus retained efficient transmission through direct contact underlines the necessity of continuous monitoring of drug resistance and characterization of possible evolving viral proteins during the pandemic.

Dataset Information

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.

Objective

Design

Setting

Main outcome measures

Results

Conclusions

Publications

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.

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