Oseltamivir reduces mortality in influenza A/H5N1 patients

A study published in the Journal of Infectious Diseases indicates that treatment with oseltamivir significantly reduces mortality in patients with influenza A/H5N1, or 'bird flu', even when given late in the course of illness.

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In humans, influenza A/H5N1 is associated with severe disease and a high mortality rate. The multinational observational study, which is the largest-ever analysis of confirmed influenza A/H5N1 cases, showed a survival rate of 50% in patients who received oseltamivir within six to eight days after the onset of their influenza symptoms, compared with 29% in patients who did not begin antiviral treatment during the same time period. In addition, these data, collected from 308 A/H5N1 patients occurring between 1997 and 2009 in 12 countries, showed oseltamivir was even more effective when treatment was started soon after symptom onset, with approximately 80% of patients surviving when oseltamivir was administered within two days of symptom onset compared to 20% survival for those who were untreated.

Prof Wiku Adisasmito from the University of Indonesia and lead author notes:

"This important study highlights a new finding, that even delayed treatment with oseltamivir offers benefits. Clearly early treatment is what clinicians should aim to initiate and retain a high index of suspicion, but if presentation or diagnosis is delayed, treatment should still be started with oseltamivir. This study also highlights the benefits of the aggregation of data derived from many cases from multiple sites."

Nancy Dreyer, Principal Investigator and Chief of Scientific Affairs for Outcome commented: "Influenza A/H5N1 continues to pose a threat to public health because of its widespread presence in birds. Given its ability to cause severe disease and high mortality, and to crop up unexpectedly, it is critical that we are prepared to have the means to cope with this. This study has shown that oseltamivir continues to work effectively against this strain and reinforces the benefits of ensuring patients presenting with influenza symptoms are promptly diagnosed and treated. It also shows a treatment benefit even when treatment initiation is delayed."